The Boring Ham Radio Part

Martial Arts Is Life

2012-01-28T10:23:00.001-05:00

I've never been remotely athletic my entire life. About the only sport I enjoyed was Volleyball, and I wasn't very good. But, my wife and I got our kids started. We were desperate to get them involved in some physical activity – lest they turn into couch potatoes like their parents. The kids enjoyed martial arts, and they stuck with it. Watching them, I would think, “I could probably do that.”

I spent my 44^th birthday flat on my back in so much pain I could not sleep. If one has never experienced back pain, it is impossible to describe. Medicines had almost no effect. The doctor suggested physical therapy. Gradually, it helped. At the end of eight weeks, my therapist told me that I knew enough to keep the pain under control.

With success of the physical therapy, my doctor did not see a need to pursue more invasive treatments. I suggested that if I lost my extra seventy extra pounds, perhaps I wouldn’t have so much pain. My doctor agreed, but when I told him I was considering Karate, he was strongly against it. He suggested Pilates instead.

That conversation kept me out of the studio for two years. I continued to do the physical therapy exercises, and began to feel stronger. Almost three years after my back injury, I decided to ignore the doctor and give it a try.

I'm glad I did.

The three years of training to obtain a black belt seemed like forever. Most most things in life, I've been a fast learner. It was difficult for me to accept such a seemingly slow pace.

In the first year, I began to understand some of the subtleties of the art. It’s not just blocking, punching and kicking, but how well one blocks punches and kicks – the correct stance, balance, body position, speed. Seemly simple exercises are actually quite difficult. And while the first one may look pretty good, but how well can you do the hundredth? Training the body this way takes time, and can’t be rushed. The repetition trains the muscles and the mind to make the motions habitually. They become second nature.

When I started, I hoped to lose a few pounds, and reshape my flabby self. In the first six months, I lost 17 pounds. Since then, while I continue to reshape, I haven't lost any further weight.

The mental changes surprised me. Within a few months, I found I could concentrate better -- I was able to think like I could in my early thirties. This sort of concentration is very beneficial in my line of work.

For some people, a black belt signifies something dangerous. They joke that you have to register yourself at a police station as a weapon, just so your neighbors will know not to mess with you. This couldn’t be further from the truth. Martial art training does not make one more volatile. With the confidence gained through training, you become a calmer, less anxious person, ready for anything.

I view the black belt as something akin to a pilot’s license. In flying, flight examiners often say that earning your Private Pilot license is the beginning of your training. The license signifies that you meet the minimum qualifications of aeronautical knowledge, piloting skills and judgment to be permitted to fly yourself and passengers. Just having the license does not signify any sort of aeronautical mastery. The true learning starts when you alone are responsible for the safe outcome of each flight. The lesson is clear: that a good pilot never stops learning.

To me, the black belt shows that one has demonstrated the minimal proficiency at martial arts necessary to advance to further study. Anyone with a black belt has put in a lot of hard work. Three years of training twice a week is three hundred lessons. For some, the number may be closer to five hundred. During that time, the student honed their powers of observation. They should be able to pick up the subtle details of instruction. Black belts have shown the mental toughness to keep going even when the body wants to stop – they won’t give up. Above all, the students have shown a willingness to learn. All of these are necessary for advanced study of martial arts. This isn’t the end of training, but the beginning.

Since earning my black belt in Tang Soo Do, I've continued to train, but circumstances have lead me to also train in Hap Ki Do and Tae Kwon Do. It's been four years now, and I don't see any signs that I want to stop. It isn't just part of my life, on some level, it is life itself.

Finishing the R7000 Rebuild

2012-01-16T23:32:00.000-05:00

At our last installment, we were going to re-assemble the R7000. But, I forget to mention one other rebuild step I performed. When I took the R7000 down, the center insulator was looking green. As in slimy mildew green. Yuck. That growth was going to slowly destroy the insulator.

Refinished R7000 center insulator.

Disassembly was the first step. I thought I might be able to separate the insulator from the aluminum tubes, and I removed the screws holding them together. With the original R7000, there are eight short screws inserted from the inside of the tubes. I'm sure they use some special jig for this, because once you remove them, you can't get them back in. That's OK, because later versions of the R7000 simply used four 2 1/2 inch 8-32 screws.

Even with the screws out, I couldn't separate the insulator from the tubing. It was just too tight a fit to try and separate and risk damaging the insulator.

With all the hardware out of the way, the next step was to clean the green slime off the insulator. Soap and water took care of that with a little gentle scrubbing with a sponge. The fiberglass was a little frayed on the surface, but the insulator looked practically new.

To prevent a new growth of green goo, I painted the insulator with a thick layer of flat black spray paint. The photo shows the screws re-assembled.

R7000 Assembled. The chair keeps the
capacity hat rods from bending.

Following the measurements in the manual, I re-assembled the antenna in the driveway. Although the manual directs you to install the radial rods first, it's much easier to work with the antenna if you leave them until later.

Once you put the capacity hat rods on, you'll need to elevate the antenna to keep them from bending. I used a patio chair for this purpose.

After finishing the assembly, I double-checked the tubing lengths, just to be sure. This is an important step. When I first assembled my Cushcraft A3S, for example, I got the lengths on the director element about 6 inches short on each side.

Before doing all the work of putting the antenna back on the mast, I wanted to make sure it was working correctly. I figured if I could hold it a foot or so off the ground, I ought to be able to see the resonance dips near each amateur band.

I used a wooden stepladder and bungee cords to hold the antenna just off the ground. Using an antenna analyzer, I found resonance dips roughly where they should be. Having the antenna so close to the ground means it's going to be slightly out of tune. But it was a good enough test to give me some confidence the antenna would be working as it should. (or, so I hoped)

Wooden stepladder used as a test stand.

After this, I re-mounted the antenna to the mast and raised it back up in position. Initial tests seemed to show good results on 10 and 12m. 15m - 20m were a bit out of whack, and 30m and 40m were pretty much unusable.

Hmm. I contemplated this problem for about a week. I figured it might be a problem with the CT1 trap. In the meantime, however, my replacement capacitor came. I replaced my chain of 4 100 pF caps with a single 27 pF 1 kV capacitor.

After replacing the MN7000, I was shocked to see no SWR dips at all on the antenna analyzer. However, punching the antenna with a little bit of RF remedied that. In fact, the antenna appears to be resonant on each of the expected ham bands with a reasonable SWR.

I used this antenna in the recent NAQP CW. It performed decently. I even managed to hold a run for about a half hour on 40m. I'd say it's now working as designed. I don't know if it will break any pileups, but having a decent radiator on seven ham bands with one eleven foot support is nice.

Rebuilding the R7000

2011-12-30T18:48:00.000-05:00

Given the number of times that Cushcraft has re-designed it's multi-band, no radials vertical, I'm not sure it has been their most successful product. The R5 / R7 designs had problems with trap stability and mechanical complexity, so Cushcraft introduced the R7000, using enclosed traps very similar to designs they used on their very successful trapped tribander series. Later this became the R6000 / R8, where some traps were exchanged for multiple vertical elements.

The R7000 also went through a trap re-design in mid-1998. There are three different manual available, the original from October 1996, one from June 1998, and the last from May 1999. The latter two are hardly different -- only a slight difference in assembly hardware. However, the 1996 and 1998 versions don't even share the same dimensions.

For those of us using the original version, there's at least one change from the 1998 version that might be worth adopting. When adding the R80 80m add-on kit, there are two tubes BH and BI that are inserted into the ends of the CT1 trap. This strengthened the tubes on the trap, which can help avoid fold-overs like this. The 1998 changes incorporated these tubes as part of the standard product. Since this only requires two pieces of 5/8 inch tubing about 6 inches long, it should be recommended for any rebuild. (Provided you can find 5/8 inch tubing)

First step on any rebuild is disassembly. My unit had seen 15 years out in the weather, but was actually in pretty good shape considering. No parts missing, and only a very slight bend in the bottom of the CT3 trap tube.

When I opened the MN7000, I found several spiderwebs and debris. Getting the circuit board out of the box requires unsoldering the SO239 center contact -- this requires a large soldering gun. Once I lifted the board out, I was surprised to find a very live spider who was not happy I disturbed his home. Sorry, fellow, but the eviction has been posted.

MN7000 after re-assembly.

I found the MN7000 in pretty good shape. None of the components seemed charred, cracked or damaged. Some of the connections on the circuit board showed a bit of corrosion, and I re-soldered some of the connections.

Unfortunately, in trying to shorten the leads on the 27 pF capacitor, I ended up destroying it. In the picture, you can see my substitute -- four 100 pF 50V capacitors in series. As soon as I get the correct part, I'll swap these out.

Pay attention when disassembling the MN7000. I found some of the hardware to be slightly corroded, along the brackets. Remove as much of this as practical.

The general advice is that high SWR on all bands means an MN7000 failure of some kind -- but I couldn't find anything wrong, other than a few questionable connections.

Not sure if the MN7000 was the problem, I turned my attention to the traps. After a short debate, I decided to disassemble all the traps.

CT3 trap disassembled. The 20m trap is on the bottom
(right) of the assembly, and the 30m trap on the top (left).

The traps consist of two nylon bobbins that are held inside the aluminum tubes by four self-tapping screws and four dimples. You have to drill out the dimples with a 1/8 inch drill bit. The top rubberized weatherproofing was removed by slitting it part way up the non-connected side (the smaller lump) and pulling it off. Try to cut as little of the weather proofing as possible. Remove the screws and pull the bobbins out, or you can tap them through (but be sure to move the aluminum wire out of the way).

CT2 trap half-way assembled. 15m trap is inside the tube,
17m trap waiting to be installed.

The traps were in pretty decent shape. The top trap bobbins were clean, with the bottom trap showing a bit of insect debris. The bottom traps showed a bit of yellowing as well. A few checks with an ohmmeter showed the connections between the wire and inner trap tube were good.

Re-assembly was easier than disassembly. Since the dimples were drilled out, I substituted 3/8 inch long #6 self-tapping screws. The alternative would be to cover the dimple holes with tape, but using screws seemed to add to the structure of the trap.

CT1 trap, reassembled on the antenna with a protective
layer of electrical tape.

Weatherproofing is held in place with a layer of tape, wound from the bottom to the top. I also added a layer of tape over the bottom screws, in order to keep the weather off the aluminum wire connection.

With all the components cleaned and re-assembled, it is time to assemble the antenna. Which we will do in our next installment.

R7000 Moves to Micro-Shack

2011-12-30T17:31:00.000-05:00

Putting up the R7000 at the Micro-Shack took a bit of doing. I didn't want to leave any concrete monuments in the yard, so I had to look for something a bit more temporary. Fortunately, there's an outbuilding behind the house that appears to be made of salvaged lumber. This little shed has seen better days, but looked sturdy enough to support wall brackets. A few 2x4 reinforcements inside the framing received lag bolts for a couple of wall brackets I had on hand.

The hard question was -- what to do for a mast? The 1 1/2 inch rigid EMT I used worked ok for 15 years, but EMT isn't meant to be a mast product. Plus, it wasn't the right outside diameter to fit the mounting U-bolts for the antenna. A 12 to 15 foot piece of 2 inch galvanized, chrome-moly steel would have been ideal, but not easy to come by.

Top end of mast, showing R7000 attached. Notice the R7000
radials are not installed. They get in the way so it is easier
just to put them on just before raising the antenna.

I ended up using an different combination. First, a 10 foot piece of 1 1/4 inch steel pipe, a 1 1/4 to 1 1/2 inch adapter, then a 12-inch long 1 1/2 inch steel pipe nipple, and finally a pipe cap. Steel pipe is quite a bit thicker than rigid EMT, and a lot more expensive. A 10 foot 1 1/2 inch pipe would have been almost $40! The 1 1/4 inch pipe was just over $25, and the 1 1/2 inch nipple made it 11 feet total height.

The 1 1/2 inch nipple fit the mounting U-bolts much better than the old rigid EMT did. Close, but not as perfect as a 2 inch mast would be.

It just took a warm afternoon to put up the brackets, assemble the antenna and raise the mast. Unfortunately, the antenna did not show the characteristic low SWR on the ham bands. Some work with an antenna analyzer showed relatively high SWR on every frequency from 7 to 26 MHz. Only on 10m did it show a slightly lower SWR of about 3:1.

Uh-oh. Looks like this 15-year-old antenna needs a rebuild.

R7000 History

2011-12-28T21:17:00.000-05:00

After my move in November 1994, it took over a year before I put up any antennas -- I was much too busy with young kids, new job, finishing the basement, etc. In January 1996, I put up a 125 foot doublet up about 15 feet and operated the NAQP CW contest. That doublet got mounted higher by the NAQP phone, and was joined with some attic antennas.

By the fall of 1996, I was in the market for an antenna that could reasonably support several bands, including the WARC bands. The R7000 seemed like a pretty nice solution -- seven bands with an option to add 80m as well. I bought one in November of 1996.

To mount it, I joined a 10 foot piece of 1 1/2 inch rigid EMT to a 12 inch steel pipe nipple and planted it 3 feet in the ground using two sacks of concrete. The pipe union was buried in the concrete. The resulting vertical pipe was about 1.9 inches in diameter -- almost large enough to fit the mounting U-bolts -- and nearly 8 feet tall.

While not as optimal as the specified 2 inch mast, this support worked very well for 15 years. I only stopped using the R7000 a couple of years ago when the coax to it was cut when the cable company re-buried the cable. (That one was cut by septic tank workers repairing the system)

The R7000 was not a great performer, in my opinion. I first called it the R7000 attenuator. I later discovered that it was designed to work at a height of 18 feet, not the 8 feet I had installed it. After a few years, I got the idea to add some radials at the base of the mast. Seven 20-foot radials made the antenna appear to work a lot more reasonably.

Since I wasn't using it at the old QTH, the R7000 seemed like the perfect antenna to move to the Micro-Shack. It required only one support, covered seven bands, and with a few radials seemed to work OK. A mediocre antenna seemed better than none at all.

The Micro-Shack

2011-12-23T23:09:00.000-05:00

It eventually happens. You get a QTH built up with a reasonable set of antennas, then you have to move. My friend Mike used to think he lived under a curse -- two years after he put a tower up, he ended up moving. This happened to him three separate times. He solved that problem when he moved last -- he hasn't put up a tower since.

My wife was moved to a new church, and with that posting came a parsonage. The little problem with the parsonage was it was a bit smaller than the previous house. So, where could I set up some radios? No more basement shack, cause, there is no basement. And there's no spare or "bonus" room. What to do?

There was a little utility room next to the car port. This is an unheated / (cooled) storage room, that houses the water heater and the electrical box. It's about 5x7 feet, and not good for terribly much. Perfect. (Well, not perfect, but it could work....)

The storage room was pretty dismal. While it had a window, the walls were thin, unpainted plywood that had seen a fair amount of abuse in 40+ years. I removed a beat-up cabinet that apparently had been salvaged out of someone's kitchen a few decades ago. A couple of coats of white paint considerably brightened the place up.

On the wall opposite the water heater, I put some adjustable shelf brackets in place, and had enough brackets on hand for five shelves. Then there was the small matter of the operating desk. I mounted 2x4 blocks on opposite walls by screwing into the studs and placed a piece of 23/32" plywood on top of them. (Do you know that it is crazy you cannot buy 3/4" plywood any more?) A couple of 2x4 blocks along the wall hold up the back end of the desk, and two strips of 1x4 glued to the bottom give it enough reinforcement that it would probably hold up my weight. Should be good enough for any boat-anchor I choose to put on it.

The operating desk fitted the space available: 5 feet 3 3/4 inches by 29 inches deep and 30 inches above the floor. The shelves just above the desk would support some equipment to free up a little desk space. It would be small, but quite usable.

Now, it's just a small matter of getting power, ground and some antennas up.

Awarded: 6B WAS

2011-10-10T22:33:00.000-04:00

I discussed my pursuit of WAS, and then 5B WAS before.

Well, after a couple of miscues, including a lost QSL card, cancelled and re-issued credit cards, and a few month-long delays -- I finally received my 5B WAS award with the 160m endorsement.

Thank you so much to the hard-working folks at ARRL HQ for finally straightening this out. It's nice to meet a goal after 35+ years of hamming. Something that only 3,004 hams before me have done.

WAS on 30m, 17m, and 12m will take some doing, but, with time, it may happen. Although, right now, I'm more interested in building my DXCC totals.

Retrospective - 1997 WWDC Fireside "chat"

2011-10-08T12:21:00.000-04:00

With this week's untimely death of Steve Jobs, I was thinking of the few times my life had intersected with Steve -- this was the closest I had come.

John Gruber recently linked to a video of this very special WWDC session. The video quality is horrible, but the talk is interesting. I remember this session well.

I was there.

I was sitting somewhere on the left aisle of the audience, about 1/3 back from the front, which was my usual spot for most sessions. It was my first experience in the "reality distortion field" of Steve Jobs. I must say, there was definitely something to it.

The moment in time this talk took place is worth noting. Steve Jobs was just an "advisor" and his opinion "didn't count." A couple of weeks after this talk, Jobs would sell all but one share of his Apple stock, which would precipitate a stockholder crisis that eventually lead to the ouster of Gilbert Amelio about a month later.

Jobs would step into the resulting power vacuum and assume control. But that hadn't happened yet.

It's most interesting to look at how Jobs answered the questions from the floor. He took each one seriously, and did not try to answer right away. It was more important to give a good answer, than give a quick answer.

There was certainly controversy at this WWDC. Apple had killed off OpenDoc, which developers had been anticipating for three years. While answering questions about Newton, Jobs pointed out the difficulty companies have supporting even one application stack, much less two. Three was almost out of the question. (And Jobs would kill off Newton as soon as he gained control that summer)

Jobs discussed many of the benefits of Rhapsody, but that concept didn't last a year. By WWDC 98, Apple abandoned the Yellow Box on Windows. The development tools were good, but perhaps 5-10 times better is something of an exaggeration.

Jobs wanted Mac cloners build whatever hardware they wanted, but wanted a lot more money for the MacOS license. Even when he took control, that wouldn't happen.

And while there was no revolution with Gigibit ethernet replacing hard drives, the network certainly plays a larger and larger role today. Most interesting near the end of this talk that Jobs describes a hand-held device that has cellular networking and a hardware keyboard -- he perfectly predicts the entry of the Blackberry, which would be announced 18 months later, and would dominate its category for nearly a decade. His vision extended even to products Apple would not produce.

AA4LR #1 Southeast Division, Low Power, ARRL 160m

2011-09-24T10:31:00.000-04:00

View of the shunt feed wires going up the tower.

I can't believe it. Before the 2010 ARRL 160m contest, I noticed that a score over 100,000 in the Southeast division might possibly win the Low Power category. As a result, I put in a pretty full effort with 100 watts and my modest antenna. I scored over 100,000, and I hoped it would last through the judging.

When the claimed scores came out on the 3830scores mailing list, it looked like I came in second place to WA1FCN in Alabama by only a couple of thousand points. We both had 689 QSOs, but he had one more multiplier -- 79 to my 78.

Well, the results database has been published. Looks like I came out on top. While WA1FCN had more multipliers, it looks like more of his QSOs were thrown out in the adjudication. I lost nine, but he lost 24, which put me ahead almost 2,000 points.

Not my first division leader low-power win -- the other came in 1989 in the ARRL Sweepstakes Phone. That was right after hurricane Hugo, and a lot of Caribbean stations were off the air.

I still can't believe it.

40 Years of Radio

2011-09-04T16:04:00.000-04:00

September 3rd brought forth some fond memories for me. It stands out in my mind because of the evening of September 3rd, 1971. I received my first radio, a Heathkit GR-81, Christmas 1970. My first logbook entries are from January 9th, 1971, since it took us a while to build, especially considering that the band "A" coil we got with the kit was defective.

For many months, I used the GR-81 with nothing more than a bit of magnet wire wound around my attic bedroom. This worked, but it wasn't very effective. I listened to some local AM stations, and a few shortwave stations. The GR-81 wasn't very sensitive on band "D", where most of the shortwave broadcast bands are, so I concentrated on broadcast band DXing.

With the summer ending and school about to start, I managed to take a trip to the electronics store and buy some wire. I believe at that time, I bought a 25 foot spool of very small speaker cord and completely unzipped it. In my youthful frugalness, I had computed that this resulted in a cheaper acquisition of 50 feet of wire than buying a 50 foot spool outright.

That 50 feet of wire went out the window of my attic bedroom, across the roof of the garage, and was anchored to a climbable tree on the other side of the yard. In retrospect, it couldn't have been horribly effective -- it was too low to the ground, being only 10-15 feet high for most of it's length.

However, it was outdoors -- this being my first outdoor antenna. The results were pretty dramatic, compared with the indoor magnet wire. That evening, I started at the top end of the AM broadcast band (band "B" on the old GR-81), and worked my way toward the bottom. I must have logged about 40 different stations, many of them new.

This experience made an impression on me. For the next several years, I always attempted to do this AM "countdown" around labor day weekend. In addition to signaling the start of the school year, it was also the start of the radio season.

It's hard to believe it's been 40 years. I still have that radio, and it's still in good working condition. And somewhere in my files I have that first logbook.

Why Scrum Works

2011-04-30T09:51:00.000-04:00

At work, we have been using Scrum methods for over two years. It has really been amazing how well this system works for us, at least for development. I only wish we could apply this technique more widely to our organization.

Perhaps some background would help. My employer, when I arrived here eight years ago, was one of the most disciplined software organizations I have ever seen. We produced a software release to the market every year, on time, with good quality. Every. Year. Features being cut before they were ever started, because there would be no time to finish them. It was truly amazing.

However, this advanced waterfall process was slowly destroying our product. There were two key issues: 1) we'd never plan anything risky, so the releases were getting blander, 2) we had no flexibility should something arise, since everything was planned out. We needed to do something else.

One of the key revelations about software development is that it is, to some degree, unpredictable. Even in very disciplined organization, you reach a point where the most extensive planning process cannot pin down every possible variable. The unexpected lurks in every project -- particularly for those projects which involve something new and unique. Those very projects you need to do to stay competitive.

Classic management would dictate more precision in the planning process, more and more research up front to prevent these unexpected events. But at some point, the up-front costs outweigh the worth of the project. Shouldn't we expend our efforts on building software, rather than building perfect plans?

Scrum does not solve the unpredictability of software development. Scrum embraces that unpredictability. Scrum gives software development teams the tools to manage and control that unpredictability, so that it does not derail a project. Part of the secret is not trying to plan everything. Strictly speaking, only one sprint is planned at a time.

So, why does this work? Why does planning just 2-4 weeks at a time work better than trying to plan it all?

There are three principles that make Scrum effective:

1) Customer Focus - when writing a story, we write it from the perspective of the customer. Completing a story means delivering a concise bit of functionality to the customer. With a completed sprint, the software ought to be in a ready-to-ship state. It's actually very hard to write stories this way. In the end, this process tends to break down large features into tiny slivers of functionality. The beauty of this process is that each bit of functionality can be prioritized against the other. Instead of doing months of work to finish a feature, we're focused on the high-priority aspects every few weeks. This can result in leaving some low-priority aspects of the feature on the table, but on the whole it gets the important aspects built and finished first.

2) Narrow Scope - nothing kills a software project as bad as feature-creep. You start working, and the list of requirements gets longer as you go, until the project will never end. You can't do this with Scrum. Each sprint is fixed in time. Each team has only so many resources. The only variable is the scope. If you discover new requirements, it isn't automatically part of the work. Most likely, you write it up as a separate story to be prioritized against the other stories.

3) Vertical Delivery - the hardest aspect of Scrum is working in a vertical fashion. You can't divide stories by discipline (eg design story, coding story, QA story), you've got to do all the design, coding, testing in the same few weeks. This forces one to think very small for each story. Vertical Delivery also affects your software designs. Many software products have inter-dependent layers (eg database, business logic, user interface). You don't have the luxury of perfecting each layer before moving on to the next. Vertical Delivery means you have to do everything in each layer to deliver the bit of functionality to the customer. The big architecture in the sky is out. Instead, you must choose a more evolutionary approach, where you have just enough architecture to get the job done for the story.

While it may seem cumbersome at first, these principles are actually a very natural process. Imagine an independent software development organization of just one developer and his cat. How would he get things done? Given the very small development team, he's not going to go off for months (or years) doing major features. Instead, he'd focus on delivering something to the customer, keep the scope narrow so he doesn't get sidetracked, and deliver all the components vertically.

Once you've got those basic principles down, the real magic of Scrum happens between sprints. Each sprint, stories are getting done, and little bits of functionality are ready for the customer. The work that gets done has a major effect on the stories remaining. Maybe we've gotten enough of the value out of Feature A, and we can now focus on Feature B. Perhaps there's some new requirement that's come up, and we really need Feature C in order to compete, or comply with a new law, or support a new platform. Prioritization occurs constantly.

Scrum keeps development teams focused on the most important work, delivering working software for customers. It continues to do so even in the face of constantly changing requirements and conditions.

You couldn't plan for that.

Six-Band Worked All States

2011-03-31T23:18:00.000-04:00

When I was a novice, I really wanted to earn the Worked All States (WAS) award. I wasn't an ARRL member at that time, but I figured I could go ahead and work the states and get the cards. Well, I did get confirmations for 30-some states, but never quite completed that award before moving to Georgia.

In the late 80s, I married, bought a house and set up a modest station, the dream of earning WAS came back. But then something happened. During SS Phone in 1988, I managed pull a sweep -- working all ARRL sections (76 at the time). I didn't just work all states, but I had worked all states in a single weekend.

Earning WAS didn't seem like enough any more. What I really wanted was five-band worked all states (5BWAS). What I'd missed though, was that you can work all the states in a weekend, but getting the cards to confirm that takes some doing. When I moved in 1994, it was far enough to reset my WAS efforts, and I hadn't even collected enough cards for basic WAS.

Logbook-of-The-World (LoTW) changed all that. Soon after signing up, the confirmations poured in. By the time the site supported the WAS award, I soon had enough to qualify for Basic and Phone WAS in march 2006. By next year, I had CW, 20m and 40m, and added RTTY in the fall of 2008, and 160m shortly thereafter.

Working all states on each band takes a little patience. The process can be accelerated by operating contests: North American QSO Party (NAQP), RTTY Round-up, and ARRL Sweepstakes (SS). It certainly helps to work all three primary modes: CW, Phone, RTTY.

Each band has its own character and challenges:

20m - easiest band to work all states. During one NAQP, I had a fabulous run on 20m, and later realized I had worked every state on 20m during that contest.

40m - certainly the second easiest. With the right conditions, 40m can be just as productive as 20m. Probably a bit of a challenge without a directional antennas.

160m - if you operate the ARRL 160m contest, as well as the CQ 160m contests, it is surprisingly easy to get 160m WAS. You don't need huge antennas. I worked all states with just a short, shunt-fed tower.

10m - if you operate the ARRL 10m contest, you can make a lot of headway on this band. The tricky part is the close-in states. Ground wave may not be effective for more than a few dozen miles, so you either have to look for backscatter opportunities, or wait for those rare conditions during the sunspot maximum where we have shorter skip.

80m - this would be easier than 160m, except that there aren't dedicated contests for this band. The hardest states are probably those farthest away. For me, this was AK and HI.

15m - short-skip makes this just as hard as 10m, but without the benefit of a dedicated contest. My last state for this one was SC.

After years of operating contests and collecting confirmations on LoTW, I just needed two to finish 5BWAS: 15m SC, 80m AK. I did some data-mining of my log books, and found I had three QSOs with SC over the years. I mailed out QSL cards with SASEs, and was lucky enough to get one station to confirm me. I'm currently waiting for 15m WAS to be awarded.

Alaska on 80m presented an interesting challenge. But, I had worked KL7RA on 160m using both CW and Phone. Seems I just had to look for AK on 80m this winter. Despite watching for spots and coming close a couple of times, I started to get worried -- spring was almost here, and it would soon become hard to work anything that far away on 80m due to summer noise.

I finally broke down an e-mailed KL7RA and asked him when he'd be on 80m. While he was QRV for the ARRL DX, I managed to miss him again. Finally, Rich agreed to a schedule.

The trick is to find a darkness path between GA and AK. The most optimum time would be right at Georgia sunrise -- but I couldn't ask Rich to get up in the middle of the night. Instead, we opted for about an hour and a half after his sunset -- which is 2:30 AM for me.

It took three tries, but we finally made the connection with readable signals. Thank you Rich!

With the confirmations in hand, I now just have to wait for the ARRL to process my 15m WAS, apply for 80m WAS and ask for the 5BWAS as well. So, very soon I will have accomplished what I set out to do over 20 years ago.

iPad

2011-02-12T10:47:00.000-05:00

OK, I'll admit. I have been an Apple fan for more than 25 years. I first laid hands on the Lisa and the Macintosh in the summer of 1984, and I began programming the Mac in August of 1984. I've been an Apple developer off and on since then. Virtually all my home computers are Macs, and I've encouraged my friends to buy Mac for years.

However, I 'm not what you call a raving Apple fan-boy. I thought the iPhone was interesting, but I wasn't one of those who stood in line for the original 2G, or the 3G, or the 3GS release. My biggest problem was that I felt I already spent far too much each month for my cellular wireless service, why spring for $30 more each month for the data service?

My wife convinced me to get an iPhone 3GS Christmas 2009. I've been using it for a over and year, and I'm pretty impressed with it. However, the screen being small there's really a limit to what you can do with it. After a year, though, I'm not going back to a feature-phone.

My wife surprised me this year with a special present for my birthday: an iPad. I had tried them out at the Apple store before, but hadn't spent a lot of time with it. After a week of using this little device, I find I am way more impressed with it than with the iPhone. The iPad may well-be a game changer. I'll say something that you shouldn't take lightly from this long-time Mac user:

The iPad redefines the paradigm of computing, the same way the Macintosh did in 1984.

Your first impression may be that the iPad is just a bigger iPod Touch. But there's a profound difference. The bigger screen invites a more immersive computing experience. Touching the screen directly creates a very intimate connection with the applications. And the use of gestures dramatically reduces the visual clutter required to drive our mouse-and-keyboard machines.

It is very hard to articulate, but I am convinced that the computing experience 20 years from now will look remarkably like the iPad, and not as much like the Macintosh. I felt the same way 25 years ago, after using the Macintosh -- and that feeling was correct. The Macintosh, Windows and even Linux machines offer a roughly equivalent computing experience: a graphical user interface, driven with a mouse and keyboard.

Straight Key Night 2011

2011-01-08T22:41:00.000-05:00

The operating desk set up for SKN 2011.

Since building the "Novice" transmitter in December 2006, I have enjoyed operating it every Straight Key Night since. It's probably the only time I have this transmitter on the air all year, which is something of a pity, I suppose.

The transmitter is paired with an equally interesting receiver. The two work pretty well together for 40m contacts

About a week before SKN, I fired up the transmitter to confirm everything is ready and found I could get no power out. I could hear the oscillator pretty well, but there was no grid current and no plate current.

Opening up the base plate immediately showed the problem: a 2.2 k 2 watt resistor in the oscillator plate circuit had overheated, and it had unsoldered itself from the terminal strip on which it was mounted. I replaced it with a 3.3 k 2 watt resistor, mainly because it had shifted in value to over 4.5 k! After that quick fix, the transmitter worked as it should.

This year was fortunate that I had my pick of operating time for SKN. As you can see in the picture, I had merely to ignore the modern equipment on the desk and enjoy exercising the homebrew year with my 35+ year old Japanese J38 clone key.

One of the consequences of being crystal controlled in the modern era is the certainty you must call CQ. This was not a problem this year at all. With 50 or so watts out, I had no trouble getting answers on my dipole. In fact, several times, I was called after finishing up a QSO.

My biggest difficulty was my arm kept getting tired. After about an hour of QSOing, I needed to take a short break to let my arm rest. Using a straight key is a lot of work.

In all, I worked an even dozen contacts. Six of those were stations in Texas. I enjoyed working Bob, KE5LYW, who I found out was a fellow pilot. I also had a great QSO with N4HAY, who was using a homebrew single-tube 6L6 transmitter running about 2.5 watts.

Close up of the homebrew receiver and transmitter. Note the
convenient location of the crystal holder this year.

Attentive readers should notice the transmitter sports a new front panel feature -- a crystal socket. This is much easier than reaching around the back of the rig to plug in a crystal when changing frequencies.

Only glitch I had was a bit of stability problem with the receiver. On a couple of frequencies, it would drift around a bit when the headphone cable was moved. If you note the very long set of adapters I used for the headphones, that may have contributed to the problem. I'll have to sort that one out for next year. Other than that, the receiver was a real pleasure to listen to, most likely due to the addition of a few capacitors.

2011 was a great outing for this homebrew gear. SKN is always a blast, and a dozen contacts this year beats any previous year. Join me on the air next year.

Bencher BY-1

2010-11-16T23:58:00.000-05:00

"I hate CW!" I heard a voice at a hamfest flea market recently. As I strolled up to his table, he followed up with, "You gotta help me by buying these keys."

I didn't feel like debating the finer points of operating CW with him. I was more interested in what was on the table: three sets of keyer paddles. The first was a a Heathkit HD-1410, which I knew to have a reputation for horrible feel. One other was a single-lever paddle, which I had no interest in. The third looked to be a Bencher BY-1.

I generally go to a flea market with a list of all the different things I'm looking for. I didn't this time, but I did remember I was looking for an inexpensive set of keyer paddles. The Bencher looked like it might fit the bill.

Back in 1979, when I was licensed as N8BHE, I found the progression of dits in my call difficult to send, so I opted to upgrade from a straight key to an electronic keyer. I bought a Ham-Key iambic paddle and built my own CMOS keyer. Now, the Ham-Key isn't the greatest paddle design. The base isn't quite heavy enough, the paddle arms pivot on large pins, which leaves some slop in the feel. But in 1979, it was only $30, and I've been using that same unit for 31 years.

I figure it is about time to get a second set of paddles. If you look around, you'll find they are not cheap. There are none you can buy for less than $50, and most of them are well over $100. The item on my list read "cheap paddles." That meant finding something used, hopefully in reasonable shape.

I had used a Bencher before, back in 1980 in the Georgia Tech club station W4AQL. I remember my first experience touching those paddles. I slapped the handles so hard the armature came off the pivot. I suppose you have to use a more delicate touch than with the Ham-Key.... But I did have some success using it. This fellow had this unit marked $20. I offered him $10, then $12, and finally we agreed on $15.

As I walked away from the table with my purchase, another fellow suggested I tear the unit down completely and clean it, and it should work great. That's just what I had in mind.

Once I got home, I put the Bencher on the workbench. It was far grimier than I remembered, with a telltale film of yellow tobacco on the base and armature. During disassembly, I found the hold screws to be hopelessly bent, and one of the screws holding the round armature pedestal nearly impossible to remove. With vice grips I removed it, but this destroyed the head of the screw.

All of the metal hardware went into a small container filled with WD-40, which did a good job of removing the latent grime. I cleaned the base and plastic parts with Windex. This took off the grime, but some of the paint came off as well -- likely due to a long-standing chemical reaction of the dirt with the paint.

No matter, a couple of coats of flat-black spray paint and the base looks good as new. Then the tedious process of putting the components back together. I replaced the four screws that I could not reuse, and quickly re-assembled the unit and adjusted it to suit my fist. I followed the excellent instructions compiled by N1FN here.

The result you see pictured above. It looks great and the feel is good, too. I'm not as ham-fisted as I was back in 1980, so I haven't had any trouble springing the mechanism. The base is way heavier than the Ham-Key, so it doesn't tend to wander as much. I believe I'm really going to enjoy working CW with my Bencher paddles.

How to Bust a Pileup

2010-11-04T00:35:00.000-04:00

I've had a great time this past month chasing the four new entities from the dissolution of the Netherlands Antilles. Even with a modest station with a small amplifier, I've been quite successful in getting through the pileups. Sure, some hams don't even have a tribander or amplifier at their disposal -- but there's no reason they can't work DX. It may just take a little more effort.

The key to busting pileups is to listen. That's what the DX experts will tell you -- and they are right. The first thing about busting pileups is not to transmit. You can't listen when you are transmitting.

But just telling someone to listen doesn't help if they don't know what to listen for. There are several things you need to listen and find before you begin to transmit.

First, you have got to hear the DX station. If you can't hear the DX, and hear him well enough to tell exactly what he is doing, there is no use transmitting at all. This can be very frustrating when you hear him work your buddies all around, but its the truth. If you can't hear 'em, don't even try to work 'em.

Next, once you can hear the DX well enough, you've got to know where he's listening. This is easy if he's working stations simplex. But, more than likely, for any reasonably sized pile-up, he'll be operating split. And that makes things more challenging.

If you have a fancy radio that allows you to listen to two frequencies at the same time, this the next step will be easier. Basically, what you have to do is listen to the DX station on his frequency, and then find the station he's working on his receive frequency.

You don't have to have the fancy radio -- you just need two VFOs and some nimble fingers. On the Elecraft K2 I use, you can hold down the A/B button, which activates the REV or reverse feature. This causes the radio to swap the VFOs it is using for receive. So, one moment you are listening to the DX station come back to someone, then you press REV to switch to the other VFO, and then hold it down while you tune around for the station being worked. But, don't hold it too long, or you'll miss the DX station's next transmission.

Sounds complicated, eh? Well, maybe. Figure also there's no guarantee you can actually hear the station the DX is coming back to. You might have to do this over and over again until you hear one. Then you have to worry that the DX station is staying in one spot -- he might be tuning around in the pileup. But the best place to be when you start transmitting is right around the place the DX station was listening last.

Once you've done this, it is probably time to start calling. If you need to tune your amp, please move a few kHz off the DX frequency before you start.

Your calls should be short -- just your full callsign, and then go back to listening. Perhaps you do this cycle two or three times, depending on the pileup. Once the DX station comes back to someone, there's no sense in continuing to transmit -- unless that stations is you.

Even though you start transmitting, you don't stop listening.

Who is the DX station working? Is he working stations in your area, or are they all on another continent? Perhaps he's working folks from all over. Listen closely to figure this out.

Who are the stations he responds to? Are they the earliest, strongest callers, or is he picking later in the pileup when the calls die down? Is he accepting or ignoring tail-enders? Figure out the pattern that the DX station is using, and use that information to place your calls better and better.

OK, you've done all that? Now is the time to have patience. Pileups can be huge random events, and if you keep on listening and carefully transmitting, you'll eventually get through. It may be on the first or second call, or it may take a half and hour of calling with no joy. Don't get discouraged.

Even so, there are a few that get away. Propagation will change, or the station will QSY or QRT. You can't help that, so don't worry about it. Most of all, don't let your worry interfere with your operating.

Careful listening can make all the difference. I've broken several pileups on the first or second call after listening to them to for several minutes. Good listening should tell you where to transmit, and precisely when.

Don't allow yourself to get frustrated and learn to enjoy the hunt.

Good DX!

Radial Clip Jig

2010-08-31T23:47:00.000-04:00

Finished Radial Clip

When I was first putting down radials, I bent a few "clips" by hand. Once I figured out that I had to have one clip every 3-5 feet of radial, I needed a better solution.

Basically, a clip consists of about 4" of 12-14 gauge copper wire, bent double, with a large enough bend radius to allow a 12-14 gauge copper wire to fit between it. The resulting clip is about 2" tall, which is about right. Any taller, and you may have difficulty pushing it into the soil without bending it.

What I needed was a jig that would make it easier to cut the wire to the right length, and then bend the clip perfectly each time, perhaps creating more than one at a time. Grabbing a scrap piece of wood and a few nails, I quickly fashioned the jig you see photographed.

The jig consists of a large 16-penny nail and a row of small wire brads. A extra wire brad is placed about 4" away from the 16-penny nail, and serves as a measuring point.

Cutting the wire

First step is to slide the wire up to the 16-penny nail, and cut it just behind the furthest brad. One can do this several times in succession to create a bunch of wires the correct length to be bent into clips.

Next the wire is inserted between the brads and wrapped around the 16-penny nail. Several wires can be stacked at once and bent at the same time. I have the best success with about three at a time.

There you have it. With the jig it is no problem cranking out 50 to 100 clips with just a few minutes of work.

Bending the clip

Laying Down Radials

2010-07-28T12:35:00.008-04:00

The key to effective ground-mounted vertical antenna is radials. While conventional AM broadcast practice is to use 120 1/2 wave radials, you don't need nearly that many to have an effective antenna. My shunt-fed 15m tall tower works just fine with 30 radials. None of these radials approaches 1/2 wave on 160m. Most are slightly less than 1/4 wave on 80m.

Even if they aren't very long, and don't come close to a hundred, it's a lot of wire to lay down. My vertical has about 2,000 feet of wire down today, and I'm looking to add about 1,000 more before the fall. It helps to have a system for laying them down.

The technique is very simple. The wire is laid on the ground, and the grass grows over it. After a few months, you will be hard-pressed to find the wire, or pull it up, even if you wanted to.

Start off by mowing the grass. You want this cut to be as short as you can make it without hurting the grass. Shorter grass will also make it a little easier to lay the wire.

Copper wire is expensive today, but is most compatible with the soil in most areas of the country. You don't need a heavy gauge. I started with some scrap 12 gauge cotton-covered wire I had. Insulation doesn't matter, and the wire should last longer if insulated. I would recommend 12 or 14 gauge THHN insulated solid house wiring, since it can be bought inexpensively at most home improvement stores. I would not suggest using anything smaller than 16 gauge, as the wire has got to take some abuse being on the ground. Hunt around at hamfests and offer to buy any spool of several hundred feet of wire for a buck or two.

At the base of the antenna, there must be some way to connect the radials. A few companies make expensive jigs for this purpose. I used a piece of 4 gauge copper wire, clamped to the tower legs. I put strips of stainless steel between the wire and the tower legs, to avoid dissimilar metals corrosion of the zinc plating. I then solder the radials to the wire ring using a 240 watt soldering gun. A little work with fine sandpaper makes this job go faster, as the copper wire has a thick layer of oxidation from being outside.

Once you've connected the radial to the base of the vertical, simply lay it out along the ground. As the ground is never perfectly flat, don't try to stretch the wire. Remember, we want to be able to mow over the wire. Stretching it will make it pop up in the low places along the ground.

To keep the wire close to the ground, so the grass will grow over it, I use a series of short clips. These are 3-3 1/2" pieces of 14-12 gauge wire bent into a U. You just fit them over the wire and press into the ground. You don't want to make them much more than 3 1/2", because they will bend when you try to push them in. You can generally do this by hand, but after putting in a few dozen clips, it will tend to hurt your thumb. I try to grab the clips with a pair of lineman's pliers and push them into the ground.

I generally walk along the wire heading away from the antenna, pushing the radial down with my foot and then adding a clip. If the soil is really dry, you may have trouble inserting the clips. In that case, you can wait for a good rain, or gently water the path of the radial. You'll need about one clip every 3-6 feet, so that's a few hundred clips if you are laying down 1,000 feet of wire. I built a little jig to make the bending process easier and more consistent.

For the next several days, it is good to inspect the radials to make sure kids or critters haven't pulled a wire up. I suggest not mowing for a few weeks. When you do, use the highest setting of the mower until the wire is clearly captured by the grass.

Radials definitely improve the performance of a vertical. Put down as much wire as you can, and you'll be pleased with the results.

A Few Capacitors Make All The Difference

2010-05-18T08:36:00.003-04:00

I've been working on my little homebrew 40m receiver. When I added an internal speaker, I found that I was getting an oscillation in the audio amplifier when turning it up loud enough to hear.

A bit of sleuthing with an oscilloscope led to an unusual conclusion. My first problem was an oscillation on the voltage regulator. I used an LM7805 regulator, but raised the ground pin up with four 1N4001 diodes to give about 7.5 volts. On the voltage input pin, I could see a .5 volt peak-to-peak oscillation at about 2 MHz. There was a smaller variation on the output pin. I pulled a couple of .1 uF multi-layer ceramic caps out of the junk box and proceeded to put them across the input and output to ground. No more oscillation in the audio amplifier.

While I had the rig on the bench, I was also trying to diagnose some harshness in the presence of strong signals. What I found was that the AGC circuit was allowing some of the received audio to make it into the AGC input of the MC1350. Another .1 uF cap on the AGC input of the MC1350 helped to smooth that out.

Another issue I tackled was the BFO frequency trim only allowed a center frequency of about 850 Hz. I added a 10 pF capacitor across the adjustment trimmer and could tune down to about 700 Hz, which is much more listenable.

Only issue I haven't figured out is a third-harmonic response around 2100 Hz in the receiver passband. Probably need another capacitor somewhere else.

In any case, about an hour of work and the receiver works well with the internal speaker, and is much more listenable on the phones.

Making Noise

2010-04-11T22:35:00.004-04:00

When calibrating the Elecraft K2 crystal filters, a noise generator becomes an invaluable tool. Using one results in clean spectrum traces. I had built an RX noise bridge some time ago from an ARRL Handbook -- the original article for that project appeared in the December 1987 issue of QST.

The noise source is a reversed-biased zener diode -- which produces noise of fairly broad bandwidth. A two transistor amplifier chain feeds the trifilar winding of the noise bridge transformer.

This circuit had the unusual addition of an oscillator to switch the noise off and on at about 1 kHz. This made for the very disconcerting effect of hearing 1 kHz tone no matter where the receiver was tuned. The noise bridge was intended to help me tune a manual antenna tuner without having to transmit, but it didn't work as expected.

The oscillator was useless for tuning the filters of the K2. I modified the circuit by removing the NE555 chip and jumpering pin 3 to pin 4, effectively supplying power to the zener all the time. (In fact, this very circuit appeared in the March 2002 issue of QST, and was also promoted by Tom, N0SS as a noise generator on his site)

However, the two transistor amplifier didn't seem to provide much output -- I got the strongest noise signal when attaching to the base of the first transistor. Perhaps this is why the tuner-tuner project didn't work so well. I suspect there's something wrong with one of the junkbox transistors I used.

My main problem was that I needed to jury-rig it with jumpers every time I wanted to use it. What I wanted was a dedicated noise generator -- which isn't much more than a zener diode noise source, followed by a broadband amplifier.

Since I didn't have much luck with the two-transistor amplifier, I thought of using something different. Mark, WA3YNO suggested using an LM703 as the amplifier. I had a better idea -- why not use a MMIC amplifier? The MMIC offers high gain, unconditional stability and an impedance near 50 ohms. I'm surprised we don't see more MMICs in amateur designs. I had a few MSA 0885's in my junkbox. Perfect.

Better engineers than I have already figured this out. If you look at the Elecraft N-gen, this is exactly what they did. So I build basically the same circuit on a piece of perfboard. The result -- S9+20 dB worth of noise. This circuit is so simple it's hard for it not to work right away. A switch is handy because the circuit draws over 12 mA from a 9 volt battery, so it won't last terribly long if you leave it on.

This noise generator works great. Make sure you don't ever transmit into it, though, as just a little bit of power will destroy the MMIC in short order. I generally use the Rx Antenna jack on the K2 (since I have the 160m module), so there's no chance of transmitting into the noise generator. Just make sure you switch the Rx Antenna off on that band, or you'll be wondering where your signals went. (Don't ask me how I know this)

Who Says Ham Radio Is Dying?

2010-04-07T21:53:00.004-04:00

OK, I've been watching this for a while now, probably since I stumbled on the site in about 2004. Set up by Joe, AH0A, it tracks statistics on the FCC amateur license database. It has been very interesting to watch.

If you look at the table of total licenses, there are some predictable things happening: Advanced and Novice licenses have been dropping off steadily since they stopped issuing them back in April of 2000. In fact, there are so few of these, I wonder why the FCC doesn't just grandfather them into Extra and Technician class, respectively.

However, the number of Extra, General and Technician class licensees have been going up for some time. After the FCC stopped testing for CW proficiency, the number of Extra class licenses has skyrocketed. Technician and General class licenses have been on the rise, too, if you overlook all the licenses being upgraded to General and Extra.

But the exciting news is that Extra, General and Technician class licenses are at record levels, and the total number of licenses has surpassed it's previous record.

While certainly not all the licensees are active, it is good to see the increasing numbers. A healthy number or licenses should keep amateur radio alive for a long time.

Configuring Elecraft K2 Crystal Filters

2010-02-28T11:57:00.004-05:00

The Elecraft K2 has a number of unique features, one is the variable bandpass filter which can be programmed for different bandwidths. This leads to a very flexible design for CW or RTTY, but requires a bit of configuration work. For each mode, you can select up to four crystal filter configurations (FL1-FL4), including using the KSB2 module filter (OP1). The first filter configuration (FL1) is also used when transmitting.

Typical configurations use OP1 in the FL1 position. For CW, I opted to use 1000 Hz in FL1, then with the progression of 400 Hz, 160 Hz and OP1 for FL4. The 1000 Hz setting is about the widest setting that still has smooth sides from a single peak. Much wider, and one side starts to get a pronounced "hump". This filter is good for general tuning on an active band. 400 Hz is great for crowded contest conditions. I rarely use 160 Hz, but it is useful for digging out weak ones. I centered these on 600 Hz. The OP1 filter is good for tuning a quiet band, but it is harder to zero-beat stations.

SSB and RTTY require OP1 in the FL1 position. On SSB, I used 1.8 and 1.6 kHz settings for FL2 and 3, but I rarely use them, the asymmetric filter makes for harsh listening.

RTTY necessitated a minor modification. During the A to B modifications, I added 47 and 100 pF caps across C174 and C173, respectively for the BFO stability mod. I changed these to 56 and 120 pF. However, this did not shift the BFO frequencies at all. I added 3 pF from the X3/X4 junction to ground and this lowered the lower BFO frequency 800 Hz without affecting the upper frequency. The wider BFO frequency range is necessary to accommodate the higher tones use on RTTY.

I originally picked the "low tone" frequencies of 1275 / 1445 Hz for RTTY. However, the resulting center frequency of 1360 Hz, can't be used with the KDSP2 filters. The KDSP2 filters can only be set to multiples of 100 Hz. So, I switched to frequencies of 1415 / 1585 Hz, nicely centered around 1500 Hz.

For the rest of the RTTY filters, I used 1000 Hz, 500 Hz and 300 Hz. 1000 Hz is good for general listening, 500 Hz is pretty much single-signal, and 300 Hz clips the edges of the signal passband, but is useful for trying to dig out stations with surrounding QRM.

Align the filters using the standard procedures for the CW and SSB filters, the RTTY filters are pretty much the same as the CW filters, except the center frequency is different. Instead of Spectrogram, I use CocoaModem on the Mac. If you go to the Config window, CocoaModem has a nice spectrum display. You can set the RTTY frequencies as markers in the window. You can see the picture at the top of the article shows CocoaModem displaying the 400 Hz filter spectrum, with markers at 550 and 650 Hz.

There's two things to know about setting the K2 filters. First, there's a limit to the resolution of the DAC used to tune the BFO -- it may not be possible to get the BFO of each filter exactly on the right frequency. The net result is that the frequency of a desired signal may shift slightly when moving from filter to filter. Second, it's important to match up both sidebands so they look and sound the same. Because of the VCO design, the K2 inverts signals above 20 MHz, so the filter used for LSB is used for USB above 20 MHz and vice versa. (The K2 firmware takes care of this automatically)

When setting up the filters, it's helpful to try to flip between opposite sidebands (using the CW RV button), and check that both sidebands sound about the same. Bumping the BFO setting by one tick can often be helpful in getting them to match.

Similarly, walk through the filter settings (using the XFIL button) to monitor any shift in the received signal. Moving the BFO setting one tick can help in some cases, but because of the DAC resolution it won't be completely perfect. With a little patience, it isn't hard to get the filters as close as possible.

The filters in the K2 offer excellent performance in an inexpensive radio, it just takes a bit of care to configure them.

WARC Trap Dipole

2010-02-21T19:54:00.005-05:00

Although I've had good success using an untuned doublet on the WARC bands, I made up my mind that it would be nice to have an antenna that didn't require a tuner.

Initially, I built this antenna has a 30m / 17m dipole. The traps are made from 1.5" Schedule 40 PVC pipe, which is about 1.9" in diameter, wound with RG-59U coax. I built them in much the same manner as those I used later in the 80/40m dipole.

The 17m traps are 35 1/2" of coax wound as 4.8 turns. I trimmed these traps to 18.1 MHz. I actually built three traps, the first was a dummy form so I could figure out where I had to drill the holes to pull the coax down tight.

The 30/17m version uses 12 1/2 feet of wire in each leg, and the outer segments are 8 feet. You may have to trim the lengths to resonate the dipole in the band.

Adding 12m requires two more traps. These were made from 26 1/2" of coax wound in about 3 and 3/4 turns. Trimming the 12m traps right on frequency takes some doing, as small changes in length can shift the frequency of the trap considerably.

I inserted the 12m traps 9 feet 5 inches from the center, and then trimmed the length of the outer legs to bring resonance within the bands. I did not do a great job of measuring -- the 12m traps ended up in slightly different locations in each leg. It does not appear to affect the antenna much.

You should measure the antenna at some height, as the tuning will change as the antenna is raised. I did my initial trimming at 15 feet, and when raised to 42 feet, the resonance frequency rose over 200 kHz on 30m, and slightly less on 17m.

I built a current balun into the center mounting box for the dipole, using 10 type 43 1" ferrite beads, slipped over coax inside the box.

Since the WARC bands as so small, antenna SWR bandwidth isn't a consideration. At 42 feet, there's a little bit of a broadside pattern on 30, more so on 17m and 12m. Since I installed this antenna as an inverted V, the pattern is a bit more circular. The traps can easily handle the 700 or so watts on 17 and 12m.

The WARC bands are a lot of fun with a decent antenna. I've worked several DXpeditions with this dipole on 17m. Without sunspots, there hasn't been a whole lot of activity on 12m yet.

This sort of antenna is easy to build and install. There's no reason lack of antenna should keep you off the WARC bands.

Trap Dipole for 80/40m

2010-02-12T19:52:00.008-05:00

At my old QTH I used an 80m untuned doublet: 125 feet fed with open wire using a remote balun. I put it up my at current QTH, shortening it to about 115 feet to fit my lot.

It worked OK for a low dipole, but it was a bit troublesome. Even with a Murch UT-2000A tuner, I had trouble using it with my amplifier. It also took time to retune when switching bands.

I decided what I needed was a trap dipole. I'd had some success building a trap dipole for the WARC bands using coaxial traps. After reading the analysis by W8JI, I still wanted to use coaxial traps, but I decided to use traps resonant off the operating frequency.

You can see the result above, about half the antenna is visible, with the feedpoint on the left, and one of the traps just to the right of center.

The traps are designed to be resonant about 6.6 MHz. They are made of 76 inches of RG-59A/U, wound in 6 and 1/3 turns around a four inch long piece of 3" schedule 20 PVC. The actual frequency of resonance isn't critical, so long as both traps are identical.

The traps are wired in series, as shown below, the inner wire (black) attaches to the center conductor of the coax, and the outer wire (red) attaches to the shield of the opposite end.

The shield of the inner end is connected to the center conductor of the outer end, as diagrammed by VE6YP.

The center section is made of two 33 foot pieces of wire. In retrospect, another foot might have been better. The outer sections started at 26 feet each. I cut off 10 feet 8 inches to bring the antenna into the band, resulting in 15 feet 4 inches. If you were to duplicate this antenna, I would start with 35 feet and 20 feet, respectively, and trim from there.

Fed with RG-8x to a height of 35-42 feet, the antenna resonates at 7.22 MHz with a VSWR of 1.5:1, and 3.76 MHz with 1:1. With the typical automatic antenna tuner in modern rigs, or the pi network of older amplifiers, this antenna easily covers both 40 and 80m. Being so low, this antenna doesn't have much of a pattern on 80m, and only a gentle broadside pattern on 40m.

I've been pretty happy with the dipole. It works well on 80m early in the evening when the propagation is short. Not bad for an antenna that's less than 100 feet long.

I hope to add a couple more traps to add 30 and 20m this summer. I'll let you know how that works out.

My Elecraft K2 Wish List

2009-10-10T16:52:00.006-04:00

I've owned my K2, SN #2548, for several years now. It has been my primary radio since the fall of 2002, when I added the KPA100 module to it. I really enjoyed building it, and I'd like to build another. A couple of years ago, when the K3 first came out, Wayne Burdick at Elecraft collected wish lists of K2 features. Given the runaway success of the K3, I have my doubts if they will ever get back to enhancing the K2, but in the spirit of hopefulness, here's my list:

Firmware-only Suggestions:

RTTY Mark Display Frequency - Just as CW displays the carrier frequency of the received CW signal, the RTTY mode ought to display the frequency of the Mark signal. A menu option would be needed to set the frequency of the Mark signal. (This would essentially subtract or add the Mark frequency from the LSB / USB carrier frequency, respectively)
VOX Toggle - I'd rather toggle VOX on and off, and have the VOX delay time set in a menu. Having to cycle through all the VOX delay times to turn VOX on and off is a real pain.
Tuning Rates should follow mode - 10 Hz tuning is fine for CW and RTTY, but too slow for SSB. 50 Hz tuning is fine for SSB. The rate button could then be used to switch to 1 kHz step and back to 10 or 50 Hz. It would save a lot of button presses trying to get the right tuning rate. You could also display all the digits of the frequency regardless of tuning step (in which case SSB would alternate the bottom digit between 0 and 5)
RIT / XIT Display - momentarily display the RIT or XIT offset on the main display when it is changed (much like for power or keyer speed).
Unified Filter - Rather than having to separately select XFIL and AFIL settings, I'd rather have three of four filter presets that allow me to combine an XFIL and AFIL setting for each mode. One button (say XFIL) would then cycle through the presets. That way, you're always selecting an optimized filter solution, rather than selecting it manually, which is made more difficult because there is no filter display indicator.
IF Shift - This very handy feature could be implemented with a firmware change. Biggest problem is how to control it. I find the XIT to be useless, so I would vote to replace XIT with IF Shift. An alternate would be to use the Keyer Speed knob in SSB or RTTY modes.
CW Tuning Direction - an option to flip sidebands on 15m and above, so that the tuning direction stays the same. (This won't work on RTTY or SSB, of course)
CW Memory Command - have a computer command to write to the CW memories. That way you can program them from the computer and use them from the front panel.
INP mode for CW PTT - This mode would allow PTT on the dot line and CW keying on the dash line - great for contesting work. (this would disable auto-detect of hand keying)
Variable Rate Turning - normal tuning is one step at a time, but if you turn the knob faster, the tuning rate increases for as long as you tune quickly.
Auto-Tuner Out -- Allow one-touch selection of Tuner AUTO/CAL. This would allow one to easily switch the tuner on and off.

Hardware Improvements:

Improved KSB2 module -- starting with a filter with sharper skirts (better than 1.5 shape factor), 6-10 dB more mic gain available, more positive VOX (using separate VOX amplifier), anti-VOX circuitry.
Improved KNB2 module -- allow selection of longer blanking times, more thresholds, better blanking action.
PFx Module -- a tiny little module that has four (or so) buttons. Hooks into the aux line and offers access to eight functions of the K2 (four on tap, four on hold). Obviates the need for FPLY, opens the K2 up for easier access to things like switching filter presets, noise reduction modes, RIT clear. Lots of simpler and cheaper than the KRC2, because it is just the buttons. (This might also be useful for the K3)
Remote Tuning Knob -- borrow the idea from Ten-Tec. Perhaps part of the PFx module.
Opto-encoder for RIT/XIT knob -- Replace the potentiometer with a optical encoder. That way, we wouldn't have to manually re-center it.

I intend to keep using my K2 for several years. It's my hope that Elecraft will be able to deliver some of these enhancements.

Cushcraft A3S/A743

2009-07-16T20:16:00.009-04:00

As mentioned before, I've been using a Cushcraft A3S for several years now. I purchased it back in 1989, had it up for about six years, in the basement for five, loaned out for a couple of years to W1YM, and then back up since 2001 at my QTH.

There's many things to admire about the A3S. It's quite rugged, having survived several freak Georgia ice storms, but it only weighs 25 lbs even with the 40m option. While it's one of the last tribanders designed without computer modelling, it has reasonable performance on a small boom of 14 feet. It's been a popular product both in home installtions and even for Field Day. I have one ham buddy who used to use one on a pneumatic mast mounted to his conversion van.

Here are some of the things that I have learned about the A3S and A743:

Tape the driven element insulator

A layer of electrical tape protects the driven element insulator from the Sun. There's not much of it exposed, but the sunlight will slowly break it down over time. Covered with tape, it will last forever. Use a sharp knife to open the U-bolt holes.

Tape the trap end caps

The plastic trap end caps won't last forever. After about 5-8 years in the Sun, they will split. Cushcraft also thinks quite a lot of them -- replacing all 24 end caps cost me almost $50 in 2000. Try to preserve them by placing a single layer of tape around the circumference of the cap where it goes over the trap tube. The flat ends don't tend to split, since they aren't under any tension.

Keep the trap holes down

While it is in the instruction manual, it's pretty easy to have an element section rotate and have one or more holes pointing anywhere but down. Leave them that way, and the traps will fill up with water quickly. Get the screw clamps on tight enough so the element sections don't rotate.

Mount traps the correct way

The traps are designed so that the end connected to the cover tube is closest to the boom. Make sure all of them are this way. If you are not sure which way they are, you can carefully slide an end cap off to check. Mark the trap tube with an arrow using a Sharpie so you can remember. If you put the trap on backwards, it may be hard to diagnose.

Use a balun

Cushcraft recommends making a balun by taking six loops of coax and taping them together. WA2SRQ wrote a posting to TowerTalk back in 1996 that showed that such a balun is much more effective when the turns are in a single layer and do not overlap or bunch. Six turns of coax on a 4 inch PVC form should work nicely. Ferrite beads a foot and a half long works well, too. I found a set of 10 of ferrite beads large enough to fit over RG-8 and wired them underneath the boom.

Twist the element support rope

With the A743 option, the driven element droops far too much, so Cushcraft includes a non-conductive support rope and support mast. The instructions show the support rope should have a twist right at the top of the support mast. The twist prevents the rope from sliding back and forth through the plastic grommet as the driven element moves in the wind. It will eventually break. Don't ask me how I know -- just remember to include the twist.

Element spacings

The A3S offers three choices of spacings along the elements, CW, MID and Phone. I took a tip from K7LXC. With the Cushcraft 40-2CD,

Steve recommends going half-way between the CW and MID settings.

The last time I had my A3S up, I used the Phone settings, and the SWR was very high at the bottom of the bands. So, I used values that were midway between CW and MID.

This results in a good compromise in covering the entire band. Here's the SWR curves through about 130 feet of RG-213.

Based on these graphs, I could probably shorten up the spacing between the 20m and 15m traps, and the 10m traps and the boom.

Regardless of the values you use, double check the measurements before putting the antenna up. When I first put up the A3S, the 10m director spacing was about six inches too short. You couldn' t tell from the SWR curves, but the antenna likely did not work as it should.

There may be better tribanders you can buy, but the Cushcraft A3S is a great performer. The A743 option adds 40m. At my QTH, this is my best 40m antenna, partly because it is mounted higher than anything else. Being able to rotate the pattern is often helpful in crowded contest conditions.

Phonetics

2009-06-26T23:31:00.003-04:00

There's been a few letters in QST lately about the proper use of phonetics. The latest QST (the one from the future -- July 2009) has an op-ed piece about phonetics.

The original letter that set this recent discussion off was a couple of months ago. The writer complained that he heard a station signing "London Radio" and thought he'd be talking to England, but was disappointed when the station was merely in the US.

That was probably me.

The writer insisted that everyone should just use the standard phonetics, and never anything else. While well intended, I'm afraid that the ICAO phonetics, while they work very well for aviation communications, don't always cut it.

"Romeo" -- this is just not a great word. It works OK most of the time, but not everyone in the world knows Shakespeare. "Radio" is a word that all hams know. It's the one phonetic that will get through when nothing else will.

"Lima" -- this is just a weak word. Watch your wattmeter when you say it -- it doesn't have that much punch. Using it, I get all kinds of guys who heard everything but the "Lima". They think it is "Charlie" or "Kilo" or "Echo" -- anything but "Lima". "London" works more often than not. About the only place that "Lima" is recognized well is in Central and South America.

"Alpha" -- try saying it twice. It comes out kinda funny. A lot of guys hear "Alpha Delta", but I also get "Delta Alpha" and "Papa Alpha" responses -- particularly from stations in europe who may be more familiar with those prefixes. At that point, the longer "America America" seems to work -- it communicates the letter as well as the country of origin.

In short, I've had this callsign for 25 years now. I've had all sorts of experience with what gets through and what doesn't. The standard ICAO phonetics don't cut it for my callsign. Pardon me if I use something a little unusual -- but it works. And isn't that what ham radio is about -- communicating?

30th Year as an Extra

2009-06-13T12:41:00.004-04:00

I was writing a note in reply to a ham who was upset that a certain DXpedition had posted operating frequencies that were all in the Extra and Advanced-class portions of the bands. He was worried that as a General-class licensee, he wouldn't have the opportunity to work the expedition.

Of course, he had nothing to worry about. These expeditions regularly listen for callers in the General-class portions of the bands. I did point out to him that between now and the time of the expedition, he had plenty of time to upgrade.

Then, it hit me. It has been 29 years since I took the Amateur Extra-Class exam.

Exams these days are pretty easy, compared to conditions years ago. Back in 1980, the FCC still administered the exams. For Extra class, code was 20 wpm, and you had to take a total of three written tests -- one for General, Advanced and then Extra. Plus, the exams were only given at FCC offices at major cities -- so, if you lived far away, you faced quite a road trip.

It was the end of my Freshman year at Georgia Tech. My family had come down to visit my grandparents, and take be back to West Virginia after finals. My brother, then KA8DTD, figured he might be able to schedule an upgrade exam before the week was out. Sure enough, amateur exams were available on Friday. Ben had a Conditional class license, and I was a General, having been tested at a hamfest just a year before. So, he scheduled both of us to take the Extra exam. Friday, June 13, 1980.

Neither of us was terribly worried about the code test, although I hadn't been down to the club station in weeks. I did borrow his Extra-Class Study Guide for that week, and managed to go over it in the midst of studying for and taking final exams.

Friday morning came, and our father dropped us off at the FCC examination building. We filled out paperwork and sat for the code test. I sweated it a little, but passed. Ben passed with no problems.

Then came the Advanced written examination. I figured it would be easy, since I studied for my Extra. Wrongo -- the old Advanced test was the largest of the bunch, with 50 questions, all of them tough. Only my private pilot's written exam was harder.

We both passed the Advanced written, and so far it had been worth the trip -- we were both guaranteed an upgrade. After the Advanced, I was convinced I was going to flunk the Extra -- but the test turned out to be a lot easier -- only 40 questions, and most of them I studied for.

After sitting through three exams over several hours, I got the news. I had passed! I was an Amateur Extra class. Ben didn't fare so well -- he had missed the Extra by one question. And that was probably because I "borrowed" his study guide all week.

So, this begins my 30th year as an Amateur Extra-Class. Hard to believe it has been so long ago.

Carlisle Tires...BOOM!

2009-05-08T22:08:00.007-04:00

Camping is fun. While tent camping has it's attractions, it's not nearly as convenient as taking an RV. With an RV, you can pack many of the conveniences of modern civilization. There are several choices with an RV. Years ago, a buddy and I invested in a camping trailer. The biggest advantage of the trailer is that once you get to the campsite, you don' t have to break camp to go somewhere, as you might do with a Class C or Motorhome.

While we sold that trailer a few years later, my family found we liked trailer camping. In 2002, we bought a new Travelstar 21SSO. It's easy to tow, light, and has plenty of room. It came with five ST175/80R13 tires made by Carlisle.

Trailer tires take a lot of abuse. They are small, and are asked to carry a lot of weight. These tires are designed to run at 50 psi cold, and the manufacturer recommends the trailer be towed with the tires inflated to that level. Even a slight under-inflation can cause tire failures.

Imagine my surprise a couple of years later when I lost two trailer tires on one trip. We were coming back from the forgotten coast of Florida, and one blew out in south Georgia. I didn't think anything of it -- I just put the spare on and continued driving home. This turned into a disaster near Byron, GA. I was watching my remaining tires in the rear-view mirror and saw one go flat. By the time I could turn off the highway 2 miles later -- the tire was completely shredded.

After losing two tires in one trip, I didn't want to repeat that experience -- so I did the most rational thing -- I called the company who sold me the trailer. I was trying to find out how I might prevent failures in the future. The dealership couldn't offer any information, other than the number of the tire manufacturer. When I called the manufacturer, before I could even ask my question, the person I was talking to told me they wouldn't give me any money. Huh?

A year later, we were headed for Florida again -- and just short of Tifton, GA, we had a tire blow out so forcefully that it broke my gray water drain valve. We immediately sought a tire store that had the right size tires. Not only did I replace the blowout, but also another tire that was showing an unusual bulge. At this point, none of the tires I was running on were Carlisle tires. I had the shop move the only remaining Carlisle tire to the spare.

Funny, I haven't lost a tire since. Last year was the final straw. I was prepping the trailer for a trip, and went to check the pressure in the spare. Now only did it not have any pressure, it would not pump up! Taking the tire cover off quickly showed why. This tire had a large crack across the tread -- which is why it didn' t hold air.

So, in six years, all five Carlisle tires failed. And the one tire, the spare, which had less than 150 total miles on it, had cracked across the tread. Today, I have three different brands of tires on my RV, and none of them have failed since they were put to use.

A couple of years ago, I asked a friend of mine who has been trailer camping for over 20 years with an A-liner how he dealt with blown trailer tires. He said in all the years he's been camping, he'd never had a tire go flat for any reason.

A co-worker of mine also bought a TravelStar 21SSO about two months after I did. He also had Carlisle tires. After three blowouts of his own, he has replaced all of them with Goodyear tires.

What conclusion can you draw from this? In my experience, Carlisle tires are defective. They clearly cannot meet the basic requirements for tires of this size. If you have any of these tires, I would strongly recommend you replace them with another brand. If you do this now, before they fail, you can shop for bargains -- rather than having to buy a tire where ever you can find one on the road.

I've had good luck with three Denman tires, even the Chinese-made SuperTrailer tires have outlasted the Carlisles.

Good tires are important on an RV. Nothing spoils a good camping trip like not being able to get there (or get home).

Shunt-Feeding a Short Tower on 80 and 160m

2009-04-08T22:42:00.010-04:00

I've operated 80m since I was a Novice. With a little room in the yard, it's not hard to put up a basic 80m dipole. Getting an 80m dipole up high enough for it to be effective is not so easy.

160m is more of a challenge. A simple dipole doesn't fit in your typical yard. A quarter-wave vertical requires quite a support structure. What we need is a effective compromise antenna.

I think it was my involvement in the NAQP that got me determined to get on 160m. I had managed to make a few contacts loading whatever antennas I had and trying to call the loudest stations on the band. After I had my tower up, K9AY encouraged me to get on the ARRL 160m contest with my 80m dipole. He also suggested that I try to put up an inverted-L. I but one up for 160m with two 100 foot elevated radials. I found the 80m dipole was more effective.

W8JI once wrote that his full-sized 160m dipoles at 300 feet were only more effective than his verticals a few percent of the time, and that was only during very unusual conditions at sunrise. The way I interpreted this was that vertical antennas can be very effective on 160m, perhaps also on 80m. What I needed was a way to put up an effective vertical antenna for 160m and 80m.

K9AY originally suggested I try to shunt feed my tower. His advice was to run a wire all the way to the top of the tower sections, then measure the impedance at the bottom, then design a matching network to match the resulting impedance. So, that's exactly what I did.

You can see the upper shunt wire mount in the photograph to the right. A piece of 1"x1" angle aluminum U-bolted to the tower provides the support for a piece of 3/4"x3/4" angle aluminum that separates two 12 gauge insulated wires. The wires are about 10 inches apart and join again another piece of 3/4"x3/4" angle aluminum fastened to a NEMA matching box at the bottom of the tower.

The shunt design has been through several iterations at my QTH. First was a single wire that was matched for 80m using an omega match. This worked ok, but I started with just seven 50-foot radials. When I added eight more, the shunt worked much more effectively.

At this point, I felt that all those radials might work on 160m, so I added an L-network that I could switch remotely with a relay. This worked until I added the A743 40m add-on kit to my Cushcraft A3S. The omega match no longer would load on 80m.

The Mark III match used a common tapped inductor for 160 and 80m, and a relay that switched in variable capacitors for each band. I had a lot of trouble with arcing. The Mark IV is what you see below. It uses a separate L-network for each band, switched in or out with a DPDT relay. Everything is contained within a 6x6x6 NEMA box shown below, which is mounted on a 1"x1" angle aluminum U-bolted to the tower.

160m is on the left. The coil uses two stacked T200-2 cores with 42 turns of wire tapped every two turns. Capacitor is a dual-section which I measured at 15-325 pF per section. The small silver-mica capacitor has been replaced with a 4 kV 160 pF disc ceramic part. The result is about 180-800 pF of capacitance, of which I'm using about 750 pF.

80m is on the right. Coil is 38 turns of wire tapped every two turns. Capacitor is a 13-250 pF unit that was the plate tuning capacitor on a Heathkit HW-40.

The photograph shows enameled wire, but I've since re-wound the 160m coil with insulated wire. Biggest problem is that the heating and cooling cycles of being outdoors cause the turns to rub against each other. This eventually results in arcing between the turns when RF is applied.

The matching networks aren't designed for a lot of power. The 80m network can manage about 200W, and the 160m network only 100w. Higher power networks would require beefier networks. Except for the NEMA box and angle aluminum, this was all stuff I had in the junkbox.

Does it work? Well, I have WAS confirmed on 160m CW, with three states left to go on 80m. For DXCC, 21 confirmations on 160, and 34 confirmations on 80. Yes, this antenna works! The key to making this antenna work well are the radials. I have twenty-five 50-foot radials, plus four 100-foot radials. Or, at least, I did. Some recent septic-tank work cut several of the radials.

I plan to lay down more this summer. I put my radials straight on the ground, held close with small loops of copper wire pushed into the ground. This keeps the wire down until the grass can grow over it. Once the grass covers them, I have trouble finding the radials.

If you have a short tower, consider shunt-feeding it to get on the low bands. It's worked well for me.

Schematic for the Step-start

2009-03-31T21:05:00.003-04:00

Dennis N2RIT wrote to ask me about the schematic for the Step-start circuit. Well, Dennis, it's pretty simple. I used the design posted by Rich Measures AG6K here. For the AL-80A, I used the +12 volt supply, which is about 15 volts unregulated. The coil of the relay I used is about 360 ohms, so to get the voltage about right, I used a 100 ohm dropping resistor.

I also added a 1n4148 diode across the relay coil to absorb the back EMF when the relay opens. Probably not needed, but it seemed like cheap protection.

Step-start for the Ameritron AL-80A

2009-03-27T18:16:00.008-04:00

For many years, I did not own an amplifier. I ran barefoot at 100 watts. You can work a lot of stations with just 100 watts. When I contest, I generally enjoy competing in the 100 watt category. But, a four years ago, I bought a used amplifier.

It had been owned by one of my fellow contest club members, K4GA. I didn't know Archie that well, aside from the e-mails we exchanged on the club reflector. After he passed away, his widow wanted his radio equipment to find a good home. I made an offer on the amplifier, and it was mine.

K4BAI later told me that this Amplifier had a bad trip to Barbados once -- it had been damaged in shipping, but had been repaired by insurance. When I got it, it needed a little TLC. The cover was on backwards, and several of the cover screws were missing. The meter switch had been replaced with one that had a shaft about an inch too long.

I fixed the meter switch with a few minutes work with a hacksaw. I bought all new screws and put the cover on the right way. The meter reading for the high-voltage was a bit low -- this turned out to be a problem with one of the divider resistors. I had much higher-quality replacements in my junk box. That fixed, the meter for high voltage read exactly as it should. The open-frame antenna relay would sometimes leave the receiver antenna disconnected. This was easily taken care of with a little contact cleaner.

This amplifier has given good service in the last four years. I've used it pretty heavily in RTTY contests, running about 400-500 watts out. I've had only a couple of complaints.

One was the jarring THUMP that would sound when I switched the power on. It didn't happen every time, but often. All that inrush current couldn't be good for the power supply components. It didn't take long to figure out I needed a step-start circuit.

Step-start is simple. Low-value resistors are placed on the main power leads. They limit the inrush current when the unit is switched on. Once the capacitors charge to a certain point, the resistors are shorted out by a relay. For the AL-80A, this is easily accomplished with two 10-ohm 10-watt resistors. Selecting the relay was a little trickier. I found a nice 12 volt relay, an Omron G2RL-24. This is a DPDT relay with contacts that can carry 8A at 250 volts. This sealed relay was only about $3.00 from Mouser Electronics.

I designed a simple circuit board for this project. It was also my first experience with TEC-200 film. The first

version of the board didn't come out too well, as I tried to flood-fill to leave as much copper in place as possible. The result was pretty ugly, because all that toner didn't stick well to the board. I probably didn't have the heat setting right. I redesigned the board without the flood-fill, and I also beefed up the size of all the traces. Getting the TEC-200 film to transfer the toner with just an iron is going to take more practice, but I'm pleased with the results.

Note from the design -- I layed out this board in 2007, but I didn't get a chance to build it until recently. I will admit that I drilled some of the component holes a little large. I'll have to remember to use the smallest of my numbered drill bits next time I make a circuit board.

The one nice thing about designing your own board -- it's guaranteed to fit your parts. There's only five components on this board, and it goes together with a few minutes of soldering.

Getting the board in the AL-80A took more doing. For one thing, it is heavy. Moving it around is not easy, and must be done with great care to avoid damage to the amplifier and also to myself.

The next problem was getting in to wire the board up. The power connections are on a barrier strip that's close to the power transformer. Fortunately, one can remove the screws and unsolder a few connections and the back panel lays down flat.

Figuring out how to connect the board was tricky. Like I said, this AL-80A had a bad trip to Barbados. The original transformer had been replaced with an AL-80BX transformer -- which also has buck/boost windings.

I ended up hooking the board from the connections from the fuses to the barrier strip. 12 volt power from the auxiliary jack drives the relay.

While I had the amplifier open on the workbench, I also added a glitch resistor to the B- lead from the rectifier stack. This is a 10-ohm 20-watt resistor. If the tube were to become gassy and short out, the glitch resistor will help dissipate the energy stored in the capacitor bank. I borrowed a couple of unused lands on the rectifier board in order to mount the glitch resistor.

Buttoning it all back up, then came the smoke test. Fortunately, I kept the smoke in. Step-start works great. No more loud thump.

The Tribander Experience

2009-03-17T23:10:00.008-04:00

Most hams start off on HF with modest antennas. Perhaps a simple wire dipole, or maybe a trap vertical. These simple antennas can work, and often work well -- when installed at the proper height and with the appropriate number of radials, respectively.

But those starting off often don't have the experience to do things quite right. My first ham antenna was a simple 40m inverted V -- it followed the roofline of the house on 6" standoffs. The apex was all of 25 feet up -- and the ends were only a couple of dozen inches from the ground. It worked, but not well. With the 50 or so watts I coaxed out of my novice rig, it did OK. I also tried various dipoles strung between trees and buildings, random wires, even a vertical made out of a slinky.

Anyone who uses these simple antennas often dreams of something better. I thought that the guys with the tribander at 50 feet had the high-end installations.

When I bought my own house, I wanted to put up some good antennas. First was a 300 foot longwire at about 15 feet high. Fed with an L-network, it could load up on all bands -- even 160m. It did not work well. For a while, I used a "Loop Skywire" -- a 80m full wavelength loop positioned horizontally. This was about 15 feet up -- just barely higher than the longwire. It worked OK, certainly better than the longwire. But really, none of these were any better than my novice antennas.

Somewhere along the line -- I had an epiphany: for horizontal antennas, the most important single dimension was the height above ground in wavelengths. I built an 80m dipole and got it up in the trees about 45 feet high. This antenna worked great -- much better than the Loop Skywire -- and it only required two supports instead of four.

I eventually put up a beam. First was a Butternut HF4B. It was mounted on a roof tower at a height of about 35 feet (10m). Certainly not optimal for a tribander. I eventually replaced the HF4B with a Cushcraft A3S. I've written about this antenna before -- it is probably one of the best of the small trapped tribanders.

When I moved to my current QTH, I decided not to repeat the roof tower experience. It took nearly seven years before I could save up enough to put up the tower. In the meantime, I used a number of dipoles at successively higher heights, a trapped vertical (the Cushcraft R7000), and even a couple of two-element delta-loop wire beams in the attic for 15 and 10m.

During this time, I had the fortune of being able to guest op at W4AN's superstation near Dahlonegah, GA. NQ4I also invited me to come and operate at his Multi-Multi station. These stations have multiple mono-banders for each band, often at heights much greater than your typical tribander-at-50-feet, and many times stacked mono-banders to certain areas. Operating at a super-station is pretty amazing.

Moving from a simple dipole or vertical to a tribander is an eye-opening experience. With a tribander, the band opens earlier, stays open longer, you have directivity that can bring stations out of the noise or null out unwanted signals. Bands you thought were dead come alive with signals. Pileups that were too big and crowded with a dipole are easily busted with the tribander.

It's curious that going from the tribander to monobanders or even stacked monobanders isn't as dramatic as the shift from a dipole to a tribander. Using a monobander or stacks is much like the tribander, only better. It isn't a sea-change.

Not every ham can afford towers and stacks, but every ham interested in HF ought to consider putting up a modest tower with a tribander. It will make a huge difference.

Amateur Receivers circa 1950s

2009-03-03T22:10:00.003-05:00

I recently read with some interest K2TQN's column about the HBR Receiver in the February issue of QST. I had never heard about this receiver until this column -- this design likely pre-dates my involvement in amateur radio by 10-15 years.

When I got into ham radio in the early 1970s, the transceiver was beginning to come of age. In the 1960s, SSB had replaced AM as the primary mode for voice operation. Transmitters and receivers for SSB have many of the same circuits -- so it made sense to share these in a single box. Before then, most hams had separate transmitters and receivers.

Looking at the HBR receiver stage descriptions, the basic design seems foreign to our modern designs. Selectivity is provided by high-Q LC circuits in the low-frequency IF near 100 kHz. But such a low IF frequency wouldn't result in very good image rejection, so a first IF near 1700 kHz comes first.

Now, in the 1950s and 1960s, the amateur bands were simpler. 160m was covered up with strong LORAN A signals and was virtually unusable. The 30, 17 and 12m bands hadn't been invented yet. So, most radios only needed to cover five bands. The HBR accomplishes this through plug-in coils.

From a modern view, the lack of bandswitching and sharp IF filtering stand out. It's hard to imagine changing bands by opening up the top cover and swapping out coils -- particularly when a couple of them have potentially dangerous plate voltages on them. Perhaps a band switch was something of a luxury.

The IF filtering confuses me. My little 40m receiver has excellent IF selectivity from just four crystals. Hams in the 1950s could have built ladder filters in their receivers using crystals from 2-10 MHz. Although, I'm not sure the ladder filter design was invented until the 1970s. Perhaps the cost of the crystals was prohibitive -- crystals are often expensive, even today.

In the same issue of QST, there was a reference to an all-transistor receiver design by W2TGP. I looked up the article in the ARRL archive. It was very odd to see a rig using all PNP transistors, especially with a +12 volt supply. (The power goes to the emitters, and the collectors connect to ground -- somewhat opposite of today's convention)

Other than the use of transistors, the design is a curious mix of older and modern elements. The rig is small, so there's plenty of room for a bandswitch for five bands. Selectivity comes from a 455 kHz mechanical filter -- 455 kHz is a bit low for good image rejection, so the first IF is around 2000 kHz.

This transistor receiver likely outperformed the HBR in terms of selectivity, but the HBR likely had better dynamic range. The single-ended mixers of the 1950s can't hold a candle to even simple Gilbert-cell mixers today.

Campground Rule for Modifying Code

2009-02-18T18:56:00.005-05:00

Dealing with other people's code challenges most software developers. If you program professionally, you can't avoid it. Any project of reasonable size requires multiple developers, meaning someone other than just you. Even if you only deal with your own code, it may look different to you later. At one job, I remember looking at something thinking, "who wrote this?" -- only to find in the comments that it was me, about 10 years earlier.

Code that has been in use for any length of time tends to rot. Design decisions that made a heck of a lot of sense five or ten years ago, when machines were less powerful and memory more expensive, seem silly -- perhaps wrong. As revision after revision is piled on, it tends to make a mess. Add to this the hands of a hundred programmers -- each one knowing the one true way to write code -- and a lot of code tends to become a hopeless jumble.

Worse, that hopeless jumble is tested and works.

As Joel Spolsky explained, modifying existing code has two dangers. First, code is hard to read, and that hopeless jumble you're trying to enhance already does things that you won't understand without a lot of work. Second, the more you alter the code, the more you'll have to retest to ensure you haven't broken the existing functionality.

Now, if you are lucky enough to have a full suite of unit tests, then you can let yourself go wild and refactor with the assurance that the unit tests will catch any errors. But this is old, revised code. Even if you have unit tests, they probably are out of date or perhaps they no longer work.

One thing that I remember from Boy Scouts -- you have to have the right attitude toward camping. Ideally, you should leave a campsite without any evidence that you had been there. That's probably not possible. But our scoutmasters had a simple for us to follow: always leave the campsite cleaner than when you arrived.

This rule applies equally well to code. No matter how badly some bit of code has been abused in the past, you can always have it leave your hands in better shape than when it arrived. If the code needs comments, add them. As you figure out how something works or some obscure requirement that's buried in the code -- note it for future programers.

If the code has a jumble of if-statements, and you can restructure it to be more clear, do so. If you find dead code, eliminate it. Just be ready to test it fully before you leave it for the next developer. No matter how much you temper your changes, you can always do something to improve the code for the next guy.

And if everyone did this, we'd have fewer hopeless jumbles.

Your Novice Accent, Revisited

2009-02-15T21:19:00.006-05:00

When I received my Novice license back in 1975, the ARRL sent me a little pamplet on the proper procedures for CW operating. It was a reprint of an article by Keith S. Williams, W6DTY from the November 1956 issue of QST: Your Novice Accent (and What to Do about It). I read it many times before I had a transmitter on the air. I'd heard some of the poor operating practices that W6DTY noted. Even in 1975, things had changed somewhat since W6DTY penned that article. Still, it was a great resource for proper operating procedures and helpful operating tips.

The Novice bands of the 1970s, 80s and early 90s were hotbeds of slow speed CW activity. Any time of the day, and most of the night, you could find QSOs in progress in the 80 and 40m Novice bands. By the 1990s, things had changed, and the code-less Technician class became the preferred entry into the hobby.

Today, the Novice bands are no longer -- and new CW operators are thrown into the mainstream, as they were in the 1940s. Although it's harder to find slow-speed QSOs on the bands to copy, and many of the operating procedures have changed. Perhaps it is time to revisit Your Novice Accent.

International Morse code is just as much a language today, although the dialect has changed. The old procedures came about from the operating practices in the 1930s, when most stations were crystal controlled. It's hard to imagine today, but a typical contact might take place between two stations who were many kHz (well, kc in those days) apart. With only a handful of crystals, hams would work across the entire band.

The Novice license originally required crystal-controlled transmitters, from the early 1950s until 1972. Most Novices in this era likely had only one or two crystals for each band. (if they were lucky)

Today's operating is almost entirely simplex -- the two stations transmit on almost exactly the same frequency. Certain types of DX and contest operation end up being split in frequency, but split is the exception.

Tune Around

W6DTY's first bit of advice -- tune around and listen. This is great advice today, but for different reasons. Of course, we no longer wait for the filaments to warm up -- solid state rigs are ready to go when switched on. We still tend not to listen much -- tuning around the band will give you an idea of what is happening. I once worked ZL4PW during a very short opening around midnight local on 30m, just from tuning around.

W6DTY advises to answer another CQ rather than adding your own. Tuning around should let you find anyone calling CQ. Given th elower activity levels on today's CW bands, often a CQ or two would be welcome -- many times the bands are open, but no one is transmitting.

If you do CQ, it's no longer expect for you to tune around many kHz for an answer. Crystal control is no longer the norm, so it is OK to expect an answer on or about your frequency. Tuning a kHz on either side of your frequency should be more than sufficient.

Calling & Answering a CQ

The form of a CQ has changed a little bit from the 1950s. While the basic three by three still applies, there's no reason to repeat this three times. Instead, the basic three by three can be interspersed with periods of listening:

CQ CQ CQ DE AA4LR AA4LR AA4LR K

... listening ...

CQ CQ CQ DE AA4LR AA4LR AA4LR K

... listening ...

Listening periods are short, just a few seconds. These short listening periods allow another station to respond without having to wait a long time.

During a contest, this process might be even more abbreviated:

CQ TEST AA4LR

... listening ...

CQ TEST AA4LR

... listening ...

Notice that we have entirely dispensed with prosigns -- the DE and K are implied.

Answering a CQ is also simplified. There's no need to repeat the CQing station's call three times. After all, he's not going to have to tune around to find you -- you should be calling close to his frequency. You still must decide how many times to send your own call. If conditions are good, once might be enough. In more marginal conditions, two or three times may be more appropriate:

AA4LR DE W1YM W1YM

(Note we've omitted the prosign AR) Quite often, operators dispense with the CQing station's call and the DE prosign altogether -- answering stations simply send their own callsign once or twice, and listen for a response.

The DE prosign is most properly used to separate the called station's callsign from the caller's callsign. If you are just sending your own callsign, there's no reason to send DE.

Making QSOs

The structure of a beginning QSO hasn't changed in 50 years. We still send RST, QTH and Name, and pretty much in that order:

W1YM DE AA4LR R TNX FER CALL BT UR RST 579 579 IN LOGANVILLE GA LOGANVILLE GA BT NAME BILL BILL BT RIG HR ... etc

Prosigns & Abbreviations

While many of the formal procedures have been dropped for brevity, we still use abbreviations for the same reason. The ES prosign is actually an old American Morse character for the and symbol (&).

W6DTY's advice about using the BT prosign as a separator of thoughts and ideas is still sound today, as well as avoiding the period and comma.

HW? is typically used today. I can't say that I've heard WATSA? recently.

Most operators today dispense with sending the AR before signing over. They simply sign over:

... BT HW? W1YM DE AA4LR K

The prosign KN seems to get more abuse than any other. It was all too commonly used on the Novice bands, and is much less common today. There's probably no need to use KN in ordinary QSOs. Just use K.

The prosign VA appears today as SK (it's the same prosign -- didididadidah, we just abbreviate it differently). Since the use of AR has diminished, SK more frequently appears as a substitute for K.

W6DTY's advice on the proper use of the R prosign is dead-on today. And, I have encountered a few operators who fall into the deadly silences. I hope I don't do that.

Sloppy sending is still around 50 years later. Although you do hear quite a bit of precise, computer-generated CW these days. It's a pleasure to listen to. Practicing sending before getting on the air is great advice today. Be sure you can handle the key or paddles with confidence.

CW remains great fun, even 50 years later. There's a timeless quality about it -- it never gets old.

My Novice Story

2009-01-31T11:06:00.004-05:00

Seeing a link to the Novice Historical Society, I thought I would write my own Novice Story.

My start in radio was pretty conventional. If you have ever read So You Want To Be A Ham, the conventional entry in amateur radio comes after being a short-wave listener (SWL). You encounter other hams talking on the air, and eventually discover you can do more than just listen. Up until the widespread adoption of SSB, this was perhaps the most popular technique for discovering amateur radio.

I got started through my brother Ben (now NJ8J). Ben is five years older than I, and my mother always joked that I wanted to do everything he did. (And she was surprised when I often could) Christmas 1969 found us with our grandparents, and my Uncle Frank didn't know what to give us boys. He ended up getting Ben a Radio Shack Science Fair Globe Patrol receiver. This was a three transistor regenerative receiver, with AM broadcast and short wave bands. Frank, Ben and Dad built it, and my Grandfather had to step in and troubleshoot it (one reverse connected diode was enough to keep it from working).

Unfortunately for Frank, that was to be his last Christmas, he die tragically in April 1970, just short of age 25. But that little radio started something for both of us. Next Christmas, our parents bought us each Heathkit short-wave radios. Ben received a GR-64, and I a GR-81. We quickly became avid radio listeners.

The GR-81 wasn't that great on short-wave, so I initially concentrated a lot of AM broadcast DXing. (Best DX was WOAI in San Antonio, TX from Fairmont, WV) Ben took to listening to more short-wave broadcast, and he quickly found the ham bands as well. Ben had learned morse code in scouts, so he was "reading the mail" on the CW bands as well.

I had tried to learn morse, and about age 14, I had convinced myself that I was just one of those people who were incapable of mastering it. Then something amazing happened. Ben got his Novice license in February 1975. Of course, I always had to do everything he did, so naturally, I started to learn the code again. I bought and built a Heathkit HR-10B, and I began to practice by listening to W1AW and the Novice bands. By November 1975, I passed my Novice license, and was WN8WOY.

Getting licensed was one trick, actually getting on the air was another. By this time, I had realised that the HR-10B was not a great receiver for CW work -- the IF response was just too wide. Using money from my paper route, I bought a used Heathkit SB-301. The difference between the two receivers was amazing. You really could listen to just one signal -- especially after I bought the 400 Hz CW crystal filter.

The SB-301 kinda broke my budget for a few months, so it wasn't until June 1976 that I could afford a transmitter, in the form of a used Heathkit SB-401. Thus, I had the matching pair of Heathkit SB-series twins. Novices were no longer limited to crystal control, so the SB-401 wasn't a bad choice.

One problem being a Novice in those days -- you were limited to 75 watts power input to the final amplifier. The SB-401 could do about 180 watts, so I removed one tube and operated that way. During that summer, the FCC changed the rules to allow Novices up to 200 watts PEP output. Of course, I didn't find out about this until the fall. The FCC also decide to drop the distinctive Novice callsigns, so in the fall of 1976, I was now WB8WOY.

The summer of 1976, I did a fair amount of operating -- a handful of contacts every day. Mostly 40m, some 80m, and a few 15m. My antenna at first was a 40m inverted-V that was mounted on standoffs just underneath the eves of the house. The ends were within about a couple of feet of the ground, so this antenna really didn't work well. I also build a small L-network tuner for the long-wire I used for SWLing for use on 80m. It didn't work well, either.

The Novice bands in the 1970s and even 80s were very different from today. Today, most evenings you could tune the CW bands and fail to hear more than a few CW QSOs, and none of them at slow speed. (Of course, if there's a contest or DXpedition active on a weekend, you'll hear lots of activity) Then, the Novice bands were a hotbed of activity, with slow speed QSOs going on all the time, every day.

In a year and a half on the air, before my Novice license expired, I made about 210 QSOs. That experience made a lasting impression on me. When I got my General class license in the summer of 1979, I often found myself operating in the Novice bands.

Three Safety Rules for Tower Work

2009-01-25T18:52:00.001-05:00

For myself, I've adopted three rules in order to ensure the safe execution of all tower work. But, before I write about the rules, I first have to tell a sad story.

When I moved to my current QTH, there was a fellow ham nearby -- he lived less than a mile from me. Though he lived in the neighborhood near me, I never met him. I believe his name was Paul.

Paul had a modest tower and tribander, like me. At a hamfest in November, a fellow ham loaned him an MFJ antenna analyzer. Paul was quite eager to climb up and make some fine adjustments to his antennas. He asked his friend if he would come over, but it was a cool, slightly drizzly day, and his friend suggested he do it at another time. Paul couldn't wait.

So, he climbed the tower himself that day. When his wife and kids came home from shopping about three hours later, they found him at the base of the tower. Unfortunately, it was too late.

Near as anyone can figure, he tried to climb while holding the analyzer with one hand, so it wouldn't be damaged. Somewhere on the way up, he lost his grip with his other hand. Ironically, he had full safety harness, but with one hand occupied, it was too difficult to clip in to the tower.

Tower climbing is a dangerous business. I knew of Paul's accident when I built my tower, so, for myself, I made three rules:

Never Climb Alone.
Never Climb Except in Good Conditions.
Always Take All Safety Precautions.

I borrowed the first rule from SCUBA diving. SCUBA divers know never to dive alone. Tower climbers should never climb unless they have at least a ground crew. If nothing else, a ground person can call 911 should anything bad happen. I've taught my kids from an early age how to properly act as ground crew. If nothing else, if I should fall and be hanging from the safety lanyard, I know someone will call 911 and get the emergency crews out there. I wouldn't want to be hanging there for hours until someone notices.

The second rule is pretty broad. Good conditions include the weather. I refuse to climb in rain, snow, windy, dark, or really hot or really cold conditions. Good conditions also apply to the climber. Tower work is demanding, physically exhausting. I refuse to climb when I'm tired, under the weather, or just not mentally "with it".

The third rule should be common sense. I climb with a full safety harness. I have a fall arrest lanyard clipped into the D-ring on my back, and it is always clipped into the tower. When I'm moving the fall arrest, I have a short 3-ft rope lanyard from the D-ring to the tower. I also always use my positioning lanyard during the climb. It allows me to stop and rest at any level.

All these precautions slow me down. I have some friends who like to free climb to the top, then they belt in. That's their prerogative -- but it's not for me. I'd rather be slow and safe than fast and sorry.

So, there you have it. Enjoy your tower, plan your climb, execute your plan, and stay safe.

The Little Receiver That Could

2009-01-17T18:22:00.010-05:00

A couple of years ago, when I build my "Novice" transmitter for Straight Key Night, I figured I had to have a receiver to go with it. I used my K2/100 as the receiver in 2007 and 2008, and nearly fried my K2/100 that second time when I accidentally hooked up the transmitter into the K2 instead of the antenna. (The K2/100 front end is really tough! It survived about 12 watts of CW for about two or three minutes)

The transmitter was built using techniques typical of the early 1960's -- all tubes, except the power supply used silicon rectifiers. I figured that the companion receiver ought to be all solid-state. And not just all solid-state -- but using nothing but integrated circuits.

Well, I'm pleased to say that I almost achieved this goal. The receiver uses one transistor, but we'll get to that in a moment.

I took my design inspiration from the Norcal Sierra, as published in the 2000 ARRL Handbook. The receiver in the Sierra uses the common NE602 Mixer / Oscillator and the MC1350 IF amplifier. An LM386 provides audio amplification.

The NE602 is a very flexible and powerful part. I'm sure the receiver builders of the 50's would have loved to have a component such as this. The oscillator block is stable, and covers a wide frequency range. The mixer is fully balanced, offers some gain, although it's dynamic range leaves something to be desired by modern standards.

The MC1350 is practically an entire IF strip in one chip. It has lots of gain, and easily applied gain control.

Perhaps the best advice for building a receiver is to start with the power supply, then proceed to the audio stages, working your way backward to the front end. Which is exactly how I began. Power comes from a 12 volt supply, but the NE602 can only take 8 volts. An LM7808 would be perfect, except I didn't have any. I did have a bunch of LM7805s, so I used one of those, and boosted the voltage by stacking four 1N4001 rectifiers in the ground lead, giving about 7.5 volts.

Next was the LM386 audio stage-- while really popular, it can be somewhat cantankerous. Initially, it was fine, but as I added stages, it become unstable and would oscillate until I put a 10 ohm resistor and .1 uF cap to ground.

An NE602 (I used the equivalent SA612A) is the BFO and product detector. At this point, the receiver was working great. Then comes the MC1350 IF stage. it was pretty painless as well, but for some reason, the radio was less sensitive than before.

Turns out I had a solder blob shorting across the LM386 inputs. I wasted a lot of time figuring that out.

At this point, I added LM324 for the AGC amplifier. I wanted to use a 8-pin chip, like the others, but all the op amps I had required dual voltages.

By the time I finished before SKN 2008, the receiver looked as on the right. You can see a four crystal ladder filter, with matching toroids on each end. You can see the schematic evolving as I build.

At this point, the receiver consists of a 4.915 mHz IF, product detector, amplifier, and audio-derived AGC. The tricky part is the oscillator and first mixer. Another NE602 stage brings the 40m band to the IF. At 7 MHz, the oscillator would be on 11.915 MHz. This had me a little worried. I remember as a Novice trying to build a 7 MHz VFO and having trouble keeping it stable. A few turns around a T50-2 toroid, and the receiver is on frequency and quite stable.

Tuning is accomplished with a 6 pF variable capacitor. This unit has a 8:1 reduction built in, and came out of a Heathkit SW-717. By selecting the right inductance, the oscillator tunes about 150 kHz, which means about 35 kHz per turn.

With the basic circuit going on the workbench, it was time to move everything to a nice-looking package. I had a nice painted aluminum cabinet that was perfect. It's always a bit gut-wrenching to drill into a new cabinet. The hardest part was getting the geometry of the tuning capacitor holes right, so that's where I started.

The tuning dial is made from a brass bushing and a piece of acrylic. It fastens to the main shaft of the capacitor, the inner shaft connects to the knob. I actually had to make two of these, as the first one didn't have enough clearance to allow for the thickness of the panel.

One item I wanted for the receiver was an S-meter. I found three surplus edge-on meters in the junkbox that looked perfect. I believe they may have been decided for CBs, as the top scale has S-units, the bottom is labelled Tx Power.

By this time, I had replaced the LM324 with the smaller LM358, but had one unused op amp -- which I used as a voltage follower on the AGC. This op amp drives the meter.

One last detail was muting the receiver. At this point, I abandoned my restricting on using transistors. A 2N3906 PNP transistor channels 7.5 volts to the AGC input on the MC1350 when it's base is grounded through a 10 K resistor.

Here's a view of the inside. I had to make a few adjustments once I started using the rig. First problem was the AGC time constant was too long. Even with the rig muted, the receiver still responds to very strong signals -- and so acts as a sidetone for the transmitter. But the audio from this drives up the AGC and it would take a while to hear anything when going back to receive. I reduced the 10 M ohm resistor to a 3.3 M ohm, and this seemed to work well enough.

Second problem was the pitch of the audio was a bit high. Adding a bit of capacitance to the BFO oscillator moved the pitch down to around 700 Hz.

The ladder filter provides a modestly narrow response, even with three crystals. Single-signal reception is easy to achieve. Tuning is a little sensitive, but does not require too delicate a touch. Audio response is quite good and very listenable. It's not really microphonic, but if you tap the case roughly, you can hear a small change in frequency. This is likely caused by the long lead to the tuning capacitor.

Rig could still use a bit of refinement. First, it needs a speaker, and could use a stereo headphone jack. Second, I'm still hearing a bit of oscillation on really strong signals, so audio amplifier is probably being over-driven. Third, the frequency dial is currently the back of an old QSL card. This rig deserves something neater. Forth, I'd like to tweak the circuit, perhaps replacing the single-ended choke on the output of the MC1350 with a full toroid transformer stage. Last, the S-meter is a bit sensitive. It tends to go to S9 even on very modest signals.

Funny how much fun it is to listen to the band with a receiver you've built yourself. I get a real kick out of it.

Putting Up a Tower - Antennas, Etc.

2009-01-09T22:27:00.014-05:00

With the tower up in our previous installment, it's now time to add the antennas, feedlines and everything else that makes the tower system work.

A tall tower is a great target for lightning, so every tower system needs a protective ground. Mine has four 10 foot ground rods -- one next to the tower base, and three others fifteen feet away, all tied together with 6 gauge copper wire.

Getting forty feet of ground rod into the ground might be a lot of work, except I built a special tool. It's a 12" steel pipe nipple with couplers on each end and a plug on one end. fifteen pounds of dumbell weights are added to the other end. Basically, it's a 15 lb sledgehammer that can't miss the end of the ground rod. I've been using this tool for years, and it works really great.

So long as the soil has a reasonable amount of moisture, you can pound in a ground rod within a foot of the ground in less than five minutes. The last foot is taken care of with an ordinary eight pound sledgehammer. During the drought in the late 1980's, the Georgia red clay was particularly difficult to put ground rods in, but this tool could handle it.

With the ground portion in hand, let's look at preparing the antennas. I purchased a Cushcraft A3S years ago. It's one of the last tribanders designed without computer modeling. It's rugged yet lightweight, and offers reasonable performance. For a small (14 foot boom) tribander, it's probably one of the better designs available.

It was up at my old QTH for about six years, then in my basement for five years, then up at Mike, W1YM's place while he was waiting for his Butternut Skyhawk for almost two years. At this point, it needed some help.

I ordered replacement trap end caps from Cushcraft -- all 24 of them. With the end caps off, I blew all the debris out of the traps. I also tightened up all the sheet metal screws which secure the ends of the traps to the elements. I wrapped electrical tape around the driven-element insulator, in order to protect it from the Sun.

As I re-assembled the elements, I chose to set the beam half-way between the CW and MID settings. I believe this is the best compromise to cover the entire band with a reasonable SWR. I got the idea from the recommendations that Steve, K7LXC made about the Cushcraft 40-2CD.

It's always a good idea to test an antenna on the ground before getting on the tower -- where it will be much harder to make adjustments. This can be done by pointing the antenna skyward with the reflector 3 or 4 feet of the ground. I used my back deck to support my antenna on a short piece of mast lashed to the deck rail.

At this time, I also added the feedline pigtail for the antenna, and the balun. Cushcraft recommends making a coil of coax feedline and taping it to the boom. While this will work, it may not be the best choice. WA2SRQ wrote a posting to the TowerTalk reflector several years ago that showed other balun designs would work much better.

Originally, I planned to add a piece of 4 inch PVC mounted to the boom with eight turns of coax. However, I happen to stumble on some very large ferrite beads that would fit entirely over RG-213 coax. They appear to be of type 77 or similar material -- excellent for a choke balun.

So the balun consists of ten of these beads, strung on the coax pigtail, held in position to the coax with wire ties. The coax is suspended below the boom with twisted 12 gauge solid copper wire.

A quick test with the antenna analyzer showed the antenna SWR curves were right where the should be -- about 50-100 kHz low because of the near effects of the ground. Now it's time to put it on the tower.

Remember, this was my first tower work. While I had done all the climbing to stack the sections, I wasn' t really comfortable with the tippy top of the tower. Once you are 20 feet above the upper bracket, there' s a certain amount of sway thats rather unnerving. Fortunately, my friend Gary K9AY was close by. Gary has much more tower experience than I, and he was kind enough to install the antenna. I was on the haul line for the gin pole, but I did managed to snap this picture as the antenna goes in place.

With the antenna on the mast, there's still much work to be done. Loosening the mast set screws the gin pole is used to move the bottom of the mast well above the rotator shelf. And then the rotator was installed. Be sure to position the antenna North to match where we left the rotator.

I routed my feedlines an rotator cable up the inside of the tower. This is much harder than just taping it to the outside of the tower, but it prevents complications if you later want to shunt-feed your tower. The cables are held to the tower alternately with electrical tape and twisted 12 gauge wire. The twisted wire is better than a wire tie, because it can be reused. It's also really cheap to salvage bits of wire out of household romex.

Remember my rotator had a defective motor cap. One really odd thing about the Ham series of rotators is that the cap is in the control box, instead of in the rotator. I opted to place the cap near the rotator by installing it in a small NEMA box that is U-bolted to a tower leg. To allow the rotator to be removed, I used two 4-pin trailer connector sets. These are inexpensive, weatherproof and very rugged. To avoid cross connecting, I used the mostly male and mostly female ends on each side. The trailer connectors join with the rotator cable inside the NEMA box.

So, in early September, 2001, my tower was fully operational.

Putting Up a Tower - Erecting the Tower

2009-01-08T22:29:00.009-05:00

In our last installment, a solid foundation for the tower had been successfully constructed. The next phase is the erection of the tower itself.

At this point, there's almost 20 feet of tower standing, but 4.5 feet of the bottom section is below the surface of the concrete, so the tower is a little more than 15 feet tall, bracketed at about 9 feet off the ground

In the picture, you can see the remaining tower sections lying on the ground, as well as the Gin pole loaned to me by Dan, W4EA.

Before erecting the tower, I had done some preliminary work. Since this was a used tower, I had fitted all the sections together on the ground to ensure they would mate properly. I also did some work on the top section.

I used the Rohn 25AG3 pointed top section. This section ends in a 2 1/4 inch inside diameter galvanized tube, which can be used to hold a mast. I wanted to make sure the rotator shelf and mast were properly aligned on the ground, so I came up with the following technique.

With the section horizontal, I fitted the mast through the top. I then mounted the rotator to the mast. The rotator is an ancient Ham-M that I found at a hamfest for $50. It needed a bit of cleanup and a new motor cap, but then it worked fine. I then mounted the AS25 rotator shelf first to the rotator, then to the tower and tightened everything down. This ensures all the parts are aligned with each other.

At this point, I used bungee cords to prop up the top section next to the standing sections and wired up the rotator for a test. The mast turned without any binding. I then removed the rotator and mast from the top section, leaving the shelf in place. Rotate to North before removing the rotator.

Before going any further, the next step is to drop the mast into the tower. This will make it much easier to later haul up inside the tower, rather than having to hoist it up and insert it down through the top section. My mast is 9 feet of 2 inch diameter, 1/4 inch aluminum tubing, donated to my project by Gary K9AY.

Stacking sections is pretty straightforward. Hoist the gin pole near the top of the existing tower, then use the gin pole to hoist the next section in place. Bolt the sections together and repeat.

I planned for brackets at 17 feet and 25.5 feet. The top bracket is just underneath the eaves of the house. After putting the third section on, I mounted the 17 foot bracket. It is tied into the rim joist with lag bolts. This is not an optimal arrangement. The lag bolts could easily pull out of the wood -- but the 17 foot bracket is just there to help stabilize the rest of the tower from flexing, and to act as a backup should the top bracket fail.

These brackets are first mounted to the tower, then bolted to the house. This ensures proper alignment between the two. Just make sure the tower is plumb before drilling into the house.

After the 17 foot bracket was in place, I removed the bracket at the 9 foot level. The next section is added, and it's time to mount the top bracket.

The top bracket gets a lot better mounting treatment. I removed part of the siding so I could get directly to the top plate of the wall. I added a 2x4 to make up the missing depth. Fastening the bracket to the tower, I then used the bracket holes as a guide and drilled entirely through the top of the wall.

Carriage bolts inserted from the inside of the wall through to the outside and secured with nuts. The ends of the bolts inside are hidden under a bit of crown moulding.

The last section is the top section, with the rotator shelf in place. Once mounted, the gin pole is used to lift the mast to the top, and locked in place with the set-screws in the top section. Tbe tower is ready to receive antennas, so we'll get them ready next time.

Putting Up a Tower - Pouring the Foundation

2009-01-07T21:31:00.021-05:00

At my last QTH, I had a tribander on a roof tower. The roof tower installation wasn't perfect -- it leaked when it rained hard. I promised myself when I moved to my current QTH 14 years ago, I would put up a real tower. I sold the roof tower and put a vertical out in the yard on an eight foot mast in the meantime.

I didn't realise but it would be seven years before I finally got that tower in the air. I really owe it to my friend Mike, W1YM. He encouraged me to put up the tower, he gave me some radio-related items before he moved to Oregon to sell to help finance the project, and he supplied lots of helpful information.

During the construction process, I took several pictures using a Casio QV-11 digital camera. This was one of the earliest consumer digital cameras, so the image quality is pretty poor. I apologize in advance for the poor quality of the images.

The process starts with the foundation. Rohn calls for rebar in the foundation, so the first we build the rebar cage. I built mine in the basement using just a piece of stout pipe to do the bending. Here's a photo of the completed product.

To keep the cage from skewing, I added some pieces of steel wire across the face to hold it square. You can't see the in the photo but they were necessary to help the cage retain its shape.

The second step was tricky. I had to make sure that the tower was placed exactly the right distance from the house. Too close, and the tower would lean away from the house, too far, and the tower would lean toward the house. The HB25B brackets I used only have adjustment holes every couple of inches.

I thought the solution was pretty clever. First, I mounted a bracket to the house at about the 9 foot level. I held it in temporarily with lag screws into the rim joist.

I used a plumb bob to drop a line down to the ground level. I build a two foot square frame using a couple of 2x4s and then placed it on a reference line below the plumb bob.

Voila! Perfect placement of the hole directly below the bracket.

I dug the hole out through the frame. An ordinary shovel worked at first, but after getting down about a foot, it was very hard to use. I ended up digging out most the hole using a post hole digger. Since the post hole digger only nibbled out a bit of dirt each time, it took a while, but it wasn't really difficult. A nursery shovel (the kind you use for planting saplings) turned out to be really handy in truing up the sizes of the hole.

With four and a half feet of my two foot square hole, the next step is to get everything in place. The bottom of the hole gets six inches of pea gravel -- which allows condensation to drain out of the tower legs. Then the rebar cage goes in after. I set mine on a set of small bricks, and made sure each side was at least three inches from the side of the hole. You don't want moisture to leach into the concrete and rust out the rebar.

Last bit to go into the hole was the tower itself. I dropped two sections in, and then fastened to the house bracket mounted earlier. I built a small wooden fixture to hold a plumb bob line in the center of the tower. On a calm day, it's pretty easy to get the tower in line with the plumb line. Rohn only specifies the tower be vertical to within 1 degree, which is readily accomplished.

Some additional wire holds the cage to the tower sections -- so that nothing will try to move around while pouring concrete.

If you look closely, you'll note one more ingredient -- a DX QSL card, which is used to ensure good performance of the antennas attached to the tower.

OK, it's time to pour!

I rented an electric mixer from Home Depot. This puppy could hold two 80 lb bags of concrete mix at once. It was tough to get it to pour into the hole, but a stout piece of plywood helped.

Each bag of mix requires a bit less than a gallon of water. I used a knife to cut the top off a gallon milk jug. When filled up, it was the perfect amount of water per bag.

The process for the pour went like this:

Pour one jug of water into the mixer. This prevent the first bag of dry mix from sticking to the sides of the mixer like, well, concrete.
Put each bag of mix into the mixer.
Start the mixer.
Add another jug of water.
Mix for about two minutes.
Pour mix into hole.
Repeat

So, you may be wondering -- when did he have time to measure another jug of water between steps 1 and 4? Well I cheated. I had a bit of help -- my eldest daughter, who happened to be seven years old at the time.

The job of filling the jug fell to her, and she was quite adept at it. We mixed 28 bags of concrete in a bit under 2 hours.

With the pour complete, it took seven days to reach 90% strength, so we had to wait for the next part -- and so will you.

Alas, Macworld, we hardly knew ye....

2009-01-05T23:53:00.005-05:00

Well, tomorrow brings the last keynote of what is most likely the last Macworld of any import. Of course, IDG may well try to host Macworld without Apple next year. We all know how well that worked in Boston.

In any case, I don't think that trade shows really matter much any more. Back in the early days of microcomputers (back when we still called them that), trade shows were a pretty effective way to generate some buzz about your new product. The first Macworld was incredibly well attended. I worked the booth for my employer -- I was scheduled for two hours on, and one hour off alternating through the day, but the reality was that I worked seven and a half hours for three days straight. My feet hurt just thinking about it. (And this was back when we wore suits and wingtips at trade shows, too)

Today, one can generate quite a bit of buzz about a new product or service just by making a press release and a couple of Twitter tweets. The internet has us so interconnected that it's just not hard to communicate.

Of course, the other thing about trade shows is that they had gotten so big that your message was getting diluted. Consider what might have happened if Apple had introduced the iPhone and CES instead of Macworld.

Chuq Von Rospach noted that Macworld caused all kinds of problems for Apple -- from people working through the holidays to messing with the delivery schedule for products. The real truth is that Apple has outgrown Macworld. Apple can generate buzz any time, just by calling a press event -- or perhaps by not calling one. That always gets the rumour mills hopping.

Apple will still have their annual WWDC as a platform for regular announcements. It's curious to me that Microsoft hasn't copied this idea. Sure, they have PDC -- but they only call for a conference when they feel there's some release of note. If they were smart, they do it every year.

Saturn S-Series: I Love Mine

2009-01-04T21:18:00.004-05:00

Back in 1994, I decided I needed to buy a car. With a new baby, I needed a four-door automobile. At the time, I was driving a 1985 Honda Accord Hatchback.It wasn't a bad car, but it got horrible gas mileage. Unusual for a Honda, you say. Well, there were reasons for this.

The original Honda CVCC engine had a carburetor. As the emission standards changed from year to year, they kept adding more devices in order to meet the standards. I once worked on a 1982 Honda Prelude. This engine had about 7 vacuum hoses. By comparison, my 1985 had 70 vacuum hoses. And when those devices were not working correctly -- the engine wouldn't quite run correctly. Honda fixed this problem in 1986, when all their cars switched to electronic fuel injection. Not so for my little hatchback.

One hot July day, the Honda finally gave up the ghost with a cracked block. At the time the Saturn S-series was pretty new, and I went to look at them. I test drove an SL1 automatic that I really liked. I also went and test drove a Honda Civic Wagon. It wasn't as nice as the Saturn, but the dealership quoted me over $4,000 more. Heck, for that price, I'd buy the Saturn. So, I did.

I drove that car like crazy for the next nine and a half years. In that time, I put 144,000 miles on it. It was a great car. Never left me stranded, got great gas mileage -- and all on very little maintenance. It was a tough little car. OK, so at 144,000 miles, it burned a bit of oil -- you generally had to put in a half quart at each fill-up. This worried my wife, so, on her advice, we traded it in on another car.

The Saturn S-series really was a different kind of car. It was a great experiment by GM -- new design, new technology, new sales team. Sadly, though, the experiment didn't pan out, and now Saturn is just another label GM sticks on platform cars designed by other divisions.

Recently, when gas prices were over $4.00 a gallon, I bought another Saturn -- an 1995 SC1 manual. Unlike my 1994 SL1, it actually has cup holders. I'm amazed at how much I enjoy driving it. This is not a sports car, or a hot rod. It's basic automobile. Plus, getting about 30+ mpg doesn't hurt, either, even with gas prices down to a more reasonable level.

Too bad GM no longer builds the Saturn S-series. With more cars likes this, perhaps GM wouldn't be needing a bailout.

"Novice" 40m Transmitter

2009-01-03T09:17:00.000-05:00

Three years ago, I discovered the remains of a project in my junkbox. It was a transmitter Istarted building when I was waiting for my Novice license, in 1975. It had seen several evolutions, but never quite worked right.

The original was a 6DQ6 crystal oscillator feeding directly to the antenna. Part of the problem was I did not have any crystals! I later changed this to a 6GK6 / 6550 design, trying to feed it with an external VFO. While the 6550 had some impressive ratings, it arced internally when I tried to feed it 800 volts on the plate. I then revised this into a 6GK6 / 6146 design following an article in the ARRL Handbook, with a built-in solid-state VFO. This actually worked, but was really chirpy and had low output. I would later discover the reason for the low output -- a bad 6146 tube.

Over the years, the useful parts had been stripped away. So, when I started, it didn't look like much, as you can see below.

The resulting transmitter uses a design similar to those popular just before I received my Novice in 1975. The power supply has an ancient TV transformer in a full-wave diode bridge that provides 800 volts to the PA and 400 volts to the oscillator. An 0A2 regulates the screen voltage to the oscillator.

The 6CL6 functions as an electron-coupled oscillator, a design I borrowed heavily from the AA8V one-tube transmitter. It keys very cleanly through the cathode, without any attempt at shaping, with no chirp or drift.

The power amplifier uses a 6146, which is biased for cutoff without drive, so I didn't attempt to key it. The bias supply comes from a low-voltage transformer reverse-connected to the filament winding of he primary transformer. This means the key only has the oscillator cut-off voltage across the contacts, which is less than 10 volts. In all the old tube transmitter designs I've looked at, I've never seen this particular keying arrangement. Cathode-keyed designs typically developed grid bias across a resistor, which meant the PA was unbiased with no drive, so it had to be keyed. Grid-block designs typically keyed all stages, or maybe left the oscillator free-running.

The 6CL6 drives the 6146 to about 2 mA of grid current (depending on the crystal), which is plenty. I originally used a 6146A that was a little soft and could only get about 40 watts out. The NOS 6146 in now gives about 110 mA of cathode current, which is about 90 watts input, and delivers a good 50 watts output.

I first used this transmitter in 2007 for the ARRL Straight-Key Night "contest". It didn't look like much as you can see, with the unused front panel holes and no cover or bottom. However, it did work pretty well.

The next year brought some changes. I removed the old front panel and built a new one that was a little bit shorter. I repositioned the meter so the whole business was a bit more compact. I added a cover made out of perforated aluminum, and a bottom panel and feed. The rig also has readable control labeling, courtesy my wife's label maker. This year, I added a T/R relay that switches the antenna and provides muting for the receiver. The result is a pretty handsome little transmitter, as you can see at the top of the article.

In the days when many people were crystal controlled, people generally tuned around for answers to their CQs, since someone answering might be many kHz off your frequency. That practice was long gone by the time I got my Novice license. Using a crystal-controlled transmitter today means you have to be able to call CQ and have people answer you on your frequency. That first year on SKN I was locked on 7075 kHz. Over the last couple of years, I've purchased about eight crystals for 40m. I've made a couple of dozen contacts with this transmitter, and it has been loads of fun to build and operate.

Of course, a transmitter needs a receiver, and that is another story.

Welcome to My Weblog

2009-01-02T09:13:00.000-05:00

With the new year, I'm sure everyone has made some resolutions. We like to think that the beginning of a new calendar means we can fundamentally improve ourselves. Let's hope so. One of my resolutions was to start a weblog -- and so, here it is.

You may be wondering about the title -- why The Boring Ham Radio Part? Well, that's a funny story. I used to work with a fellow here in Atlanta, and discovered he was an amateur radio operator. We became fast friends. As fate would have it, Mike changed jobs and moved away. But, we still kept in touch.

He and his wife Lisa (also a ham) send out a long letter with their Christmas cards. I always enjoy reading this letter. They talk about their many cats, their hiking and vacation trips, and anything else interesting they have done. The part that I read first, however, is the part that Lisa always marks "Here comes the boring ham radio part."

So I guess boring isn't so bad.