Wednesday, February 21, 2018

Hakko FK-888D

Hakko FX-888D standing ready on the corner of the workbench.
If you're going to build something, you need a soldering iron.

My original soldering iron was a crappy Radio Shack unit that got way too hot and burned tips up on a regular basis. I hated it.

At some point, I upgraded to a Weller WP-25 soldering iron. I'm not certain when I bought it. It's been at least 30 years, perhaps 40 years. I can't remember if I used it to build my SWTPc 6800 computer system in 1977 (and that's another story). But it did a fine job putting together the venerable Elecraft K2/100.

The ancient WP-25, still going strong.
While the Weller WP-25 has gotten long in the tooth, it keeps on going. A couple of decades ago, I dropped it and cracked the black plastic hand guard. It has since been held together with electrical tape. I have purchased two soldering iron holders for it, and worn one out completely. Despite the age and abuse, the iron still works quite well. Plus, I have enough replacement tips for a lifetime. I think I'm on my second or third -- they last forever.

So, how did I end up with the Hakko FK-888D? Dumb luck.

Every year, I share a Christmas list with my extended family. This year, I decided I'd like a soldering station, but not something too expensive. I found that the Hakko FK-888D could easily be had for less than $100. So, I put it on my list.

Lo and behold, my Dad purchased one for Christmas.

While I can't say I'm thrilled with the bright blue and yellow colors, the unit does sit well on the desk. The soldering pencil is slim, but it goes easily into the holder. The holder has both a scraping wire and a sponge -- great tools for maintaining a clean tip.

The station unit sits rather tall, but is so heavy there's no danger of it falling over. It's virtually all metal transformer inside. The user interface is a bit awkward: Three 7-segment LEDs and two buttons are it. You'll have to run back to the manual to figure out how to configure anything.

First turning it on, I was surprised at how fast it warmed up. The old Weller took at least 3-5 minutes before it was ready. The Hakko was ready to solder in less than a minute!

The default temperature is 750 degrees F. I backed this off a bit to 700 degrees F. That's plenty hot enough to melt solder.

I've only used this iron a little bit, but I'm amazed at how well it works. It heats up the work quickly, melting the solder soon after application, even on junctions with large terminals or lots of wires. I used it to desolder an old piece of equipment, and the job went very quickly.

I'm looking forward to building something with the Hakko. I think I'm going to like it.

Monday, February 5, 2018

The Venerable Elecraft K2/100

Elecraft K2/100 with KAT100 tuner, as it sits on the desk.

I cannot believe it has been fifteen years since I built the Elecraft K2/100!

When I first got interested in amateur radio, in the mid-70s, I wanted to build my own rig. While I studied for my novice, an elmer of mine insisted that each ham should build his own transmitter. He gave me some parts, and I made an honest attempt, but the "Novice" Transmitter didn't actually work until many years later.

Later, while preparing for college, I tried building a QRP transceiver I might use in the dorm. I built a 7 MHz FET VFO, a direct-conversion receiver, a 3 watt transmitter, and a even a KOX or Key-Operated Switch to do semi-break-in with side-tone and an relative power and S-meter.

This design never did work. Never heard a peep out of the receiver. While the transmitter produced a couple of watts output, it couldn't decide if those watts were on 7 MHz or 14 MHz. The key mistake I made in my youth was building the entire project before testing anything. The VFO worked, the KOX worked, but that was about it.

I had tried to build my own designs, without a lot of success.

I noted the Elecraft K2 introduction in 1999 with interest, but I wasn't excited. While relatively inexpensive, it only produced 10 watts output. I needed a replacement for the venerable Kenwood TS-430S, and that meant 100 watts output. When Elecraft announced a 100 watt PA for the K2 later in the year, I was hooked. Best of all, I could buy the rig in installments, adding options over time.

I joined the Elecraft mailing list, and read everything I could about this great little rig. Sold! On March 1, 2002, I placed an order for a plain Elecraft K2/10 and would receive Serial Number 2548.

On arrival, I spent and hour or two each night building. This wasn't something you could knock together in a couple of evenings. I wanted to do a good job as well, to savor the process, instead of just slap it together. In total, the basic K2 took me nearly 30 hours to build.

Wayne Burdick (one of the Elecraft founders) at some point asked me for any building notes or comments on the K2. This gives you an idea of how grassroots a company like Elecraft is. I sent him a series of four notes with my impressions and some detailed comments. I don't know if he actually used this material to improve the K2 assembly manual, but it's a nice thought.

The K2 is no Heathkit. A real Heathkit would have more drawings and diagrams at each stage of assembly. But, hey, Heathkit is out of business and Elecraft is not.

Any K2 builder can spin yarns about the joys of winding toroids. There are dozens of them in the K2. Frankly, I didn't have that much trouble winding toroids. Tinning the toroid leads, on the other hand, was a real pain. Especially when I didn't tin them up quite far enough and had to do it over.

After 20 hours of construction, I did the Alignment and Test II section and was listening to 40m signals coming through the receiver. Given my previous experience, this was very exciting. You have such a feeling of accomplishment when something you built actually operates.

For the most part, the K2 worked flawlessly after construction. I did have a problem with flaky AGC action, which was fixed with a resistor substitution and a replaced transistor. I also had an intermittent INFO 080 (the dreaded AUXBUS failure) which was caused by a bit of waxy burnt flux between two pins on the control board. The Elecraft mailing list and support email address gave me the information I needed to diagnose these problems.

With the basic K2 built, I started ordering and building options. The KSB2, the SSB module, was up first. The KSB2 has the densest board of all the K2 kits, making it the hardest to assemble. And the FT23-43 cores were so tiny, I originally thought they were fiber washers.

After the KSB2 came the KAF2. I had read enough to know that the K2 audio had an unpleasant hiss that was knocked out by the KAF2 audio filter. Beyond that, however I never found the audio filter to be that useful. While the KAF2 also has a real-time clock, I never found much use for it.

Next was the KNB2, the noise blanker. Having used the one on my Kenwood TS-430S, I felt that a noise blanker would be a required option. But the KNB2 isn't terribly effective at eliminating the noise sources I most often encountered. I was able to determine it was working, and later managed to make modifications to improve it's effectiveness.

The last option for the basic K2 I built was the K160RX -- which has to be the simplest option board I've built. Once installed, I had a very functional K2, with 160-10m coverage, CW, SSB, Noise Blanker, Audio filter. All I needed was to wait for the KPA100 option.

And, indeed, as soon as it was available to order, I placed my order the same day. And then I waited.

Fate intervened, however. While I was waiting for the KPA100 to ship, I was laid off from my job. This was the summer of 2002. The internet bubble had burst, and there were several shocks to the economy, what with the 9/11 tragedy, and the Enron and Adelphia Cable financial scandals.

Without employment, spending hundreds on the KPA100 didn't seem wise and I cancelled my order. I feared I might need to sell my K2. It took me nearly four months to find a new job, as the market was really tight. But as soon as I had a new position in hand, I re-placed my KPA100 order.

I had some trepidations about the KPA100, but it went together pretty easily, and it worked like a charm right from the start.

At this point, the K2/100 became my main rig. With computer control -- something that I had coveted for years -- contest band changes became much easier. I loved it.

Close up of the friendly face of the K2. 
Once built, for a few years I was regularly tearing into it to make modifications. The improved 2nd XFIL mod, the KI6WX improved CW filter rejection mods, alternative AF gain control. The massive A-to-B upgrade. The BFO temperature stability mod. Redoing all of the crystals with the K2KSB2XTALS mod. The KSB2 firmware update to v1.08. The PLL temperature compensation mod. The KPA100 Rev B upgrade with upgraded shield. K2 firmware update to v2.04. K2 Keying modification. The QSK improvement modification. KPA100 current consumption mod. The power control mod.

During these first few years, I also added the KAT100, the KDSP2 and my favorite, the Finger Dimple. The KAT100 really made the rig more versatile. The KDSP2 helped out on SSB with some needed bandwidth filtering, and the auto-notch filter. But the Finger Dimple made tuning the rig a much more comfortable proposition.

From Mid-2005 until 2010, K2/100 served as my main rig without any modifications. 2010 brought a flurry of final mods. The VCO Shielding mod. The KPA100 Rev D upgrade. The KNB2 response and threshold sensitivity mods.

Once I finished all this, I bought the Rework Eliminators kit -- that enables one to swap out option modules without making changes. I don't believe I've used them.

Although the K3/100 replaced the K2/100 as my main rig, I still use the K2 regularly. It is pleasant to listen to and quite capable. The K2 has earned an honorable place on my operating desk, and deserves to be called a venerable rig.


Wednesday, December 13, 2017

Brake Delay for Ham-M and Ham-II Control Boxes

A $30 hamfest find - CDE Ham-II rotator control box.
Proudly installed in the operating position.
When I put up my tower in 2001, I'd had read enough on the TowerTalk mailing list over the years to know about the importance of brake delay. This allows the rotating parts on the tower to coast to a complete stop before the brake wedge on the CDE rotator design engages. Without it, the rotator comes to a sudden and abrupt stop, causing a lot of torsional stress and making the antenna and tower elements wave around unnecessarily. That repeated stress could end up causing failures over time.

The original Ham-M design has no delay. Pushing the lever a little bit illuminates the meter and shows the position indication on the meter. A little more turns the rotator. The moment you stop pushing far enough to turn, the brake solenoid releases and engages on the rotator shell -- causing the sudden stop.

The original design schematic, sketched out in 2001.
Back in 2001, I came up with a very simple circuit. I had some Allied Controls 12 volt relays with a 1000 ohm coil. I figured I could rectify some of the AC from the motor terminals with a big enough capacitor to power the relay for a few seconds. I ended up drawing the circuit to the left.

50 volt PIV rectifiers might not be quite enough, so I wrote 100 v PIV on the design. I ended up using 1N4003 rectifiers which are 200 volt PIV.

I estimated 10 mA of current is necessary to keep the relay closed. Since the left and right motor connections are about 30 volts AC, rectified this would be about 42 volts. Putting a 2.2 K ohm resistor in series drops the voltage down to something less than 15 volts across the relay. All that remained was choosing the right sized capacitor. I had some 1000 uF low-profile capacitors in my junk box, so that was perfect, right? The RC value was around 3, so I expected a delay around  three to four seconds.

Imagine my shock when I actually built the thing and found it took something closer to fifteen seconds for the relay to open! Clearly, a lot less than the full 10 mA was necessary to hold the closed relay closed. I ended up modifying the circuit by placing a 1 K ohm resistor in parallel with the relay. This resulted in a delay closer to six seconds, which was just fine. The relay contacts are wired across the switch contacts for the solenoid, so the solenoid remains activated until the relay opens.
Relay board shoehorned in control box.

I built the circuit on a tiny piece of perfboard just a little bit bigger than the relay. Biggest problem was shoehorning it into the very crowded Ham-M control box.  I figured I could mount it on a right-angle bracket just behind the meter.

Wiring it into the circuit was harder. Assembled, the switch contacts of the Ham-M are inaccessible. I had to remove two sheet metal screws holding the meter panel to the base. That gave me access to the switch. After soldering up the leads, the meter panel goes back in place.

This circuit has been in use since 2001, and has worked great.

At a recent hamfest, I found a deal: a relatively pristine Ham-II control box for only $30. I bought it, brought it home and immediately determined it worked great. It would take the place of the Ham-M control box -- but it needed a brake delay.

The Ham-II design has three buttons. The center button supplies power to the brake solenoid and must be pressed for any power to reach the motor windings. Proper technique would have you press the center button and hold it, then engage the left or right button, holding until the antenna had moved to where you want it, releasing the left or right button, while continuing to hold the brake in with the center button.

Ham-II control box with brake delay installed.
However, if you just pop off the buttons, the brake wedge would slam into the rotator shell.... Not what we want.

It wasn't hard to find the same parts in the junk box. Another scrap of perfboard, a few minutes of soldering, and the same circuit was again created. Mounting in the Ham-II box is a much easier exercise, since there's plenty of empty space. Because four of the connections are to the switches, I elected to mount the board on the bottom of the box, just behind the switches. A threaded standoff was used on an existing screw to hold the board slightly above the switch contacts. The standoff also supplies the ground connection.

This circuit works great. In the Ham-M, the meter and lights would go off once the relay disengages. In the Ham-II, the meter and lights are on any time the box is turned on. It might be nice to have an indicator that the brake is engaged. Perhaps this will be a future addition.

Friday, November 24, 2017

Forty Years of Personal Computing - First Steps

As my present for Christmas of 1974, my older brother gave me a one year subscription to 73 Magazine, starting with the January 1975 issue. This was pure genius on his part. He knew I was showing an interest in amateur radio, plus he would have the opportunity to read my copies, so he didn't need to continue his own subscription. I enjoyed the magazine so much, I continued my subscription until the magazine's demise in 2003.

1975 an exciting time in the world of the electronic hobbyist. MITS introduced the Altair 8800 in November of 1974, and other vendors soon jumped into the market. Microprocessors and related components were coming available, and 73 Magazine was writing all about it.

With the February 1976 edition, 73 Magazine added a special section called I/O, to talk about the developments with these Microprocessors. To my teenage mind, I just had to have one of these machines. They were expensive, but I slowly saved my money from my paper route.

By the spring of 1977, I fell prey to a surplus equipment advertisement from Verada 214. The ad promised a complete system with a keyboard, display, microprocessor and dual cassette decks -- the Viatron 2111 -- only $699! It seemed like a perfect way to enter into the budding world of microprocessors without spending a fortune. Although the equipment arrived as advertised, there was no microprocessor to be found -- nor any way to program the device. After studying it thoroughly for a week, I decided the purchase was a mistake. My father managed to convince the company to refund my purchase price for the cost of shipping it back.

My father could see the seriousness of my interest, so he signed me up for a summer course at the local college where he worked. This was a six week course, and the first three weeks were spent on learning about VCR and other television technology. (It really is too bad that Quasar Alpha-wrap video cassettes didn't catch on -- but they were HUGE) But the last three weeks included plenty of hands-on time with a KIM-1, the 6502-powered single-board computer. Forty years later, I can't remember what programs I wrote, but I thoroughly enjoyed that first taste of programming.

About this time, a computer shop had opened up in Morgantown, WV, about 20 miles away from my home. My parents took me there a few times. I was fascinated to see the MITS and IMSAI equipment I had read so much about over the last couple of years. But the prices were beyond my reach. These systems cost upwards of $2000, much more than I had to spend. I'd have to wait for something more affordable.



Saturday, October 7, 2017

WARC Dipole Repair Complete

Yours truly mounting the antenna near the
top of the tower.
Well, if that didn't seem like it took forever. Back in early September, I took down the WARC Dipole. Although I quickly determined that one of the 17m traps was irreparably damaged, I didn't think it was going to take more than a month before I got the antenna fixed and back up in the air.

I made two new traps using identical lengths (35.5") of RG-58 coax. I didn't bother to try to trim these to any precise frequency. I just made the two traps as identical as I could, and that seemed sufficient.

With the traps back in place I didn't want to re-mount the antenna until I was sure all three bands were squarely in a useful part of the SWR curve. To accomplish this, I used the rope and pulley I had attached near the top of the tower. I used a carabiner through the U-bolt to lift the assembly near the top of the tower.

This actually worked pretty well, as I was able to get the apex of the antenna within a foot of it's mounted height. A 55 foot piece of coax allowed attachment to my MFJ-259 antenna analyzer.

First measurements showed the antenna to be off on all three bands. That wouldn't do. Since I had originally hacked in the 12m traps to a 17/30m dipole, I hadn't done a good job of making the wire lengths symmetrical. This was contributing to bad SWR at resonance. So my first trimming was to make the two legs equal, and subsequent trims were to both legs.

The process goes something like this. Attach the antenna to the carabiner, haul to top of tower. Take rope from one leg and attach it to end of old playground. Pull the other rope through a pulley on the other side of the house until it is above the roof line. Attach the coax to the antenna analyzer, take measurements of resonance and the 2:1 SWR points. Loosen the rope on the side of the house and get the antenna past the roof line. Untie the other rope from the playground. Lower the antenna to the ground. Untangle it all and drag it into the basement so it can be trimmed. Repeat this process.

Honestly, I didn't think I would have to do this eleven times! Both 12m and 17m were resonating slightly low, so I carefully trimmed the 12m portion until resonance occurred in the band. Then repeated the process with 17m. Once each band was in the right place, I soldered the connections between the wire and the trap. Trimming past the trap does not appear to affect the inner doublet, which is what we expect.

30m was a problem. It was resonating slightly high. I ended up splicing in about 14" of wire, split between the two legs. This was too much. In the end, I only needed 3 1/2" added, and that only to one unbalanced leg.

Managed to work ZD7BG just a few minutes after getting this antenna back up on the tower. It's really nice to have a working antenna again. Now the next repair is to figure out what's wrong with the A3S.

Friday, September 22, 2017

Life after 5BDXCC

For the last several years, I've started off the late summer thinking about my plans to complete 5BDXCC. This has meant figuring how who to make more DX contacts on 80m, whether that meant improving antennas or just being on the air more.

But, this June, I managed to wrangle enough confirmations to qualify. I'll likely submit these in November.

As that time of the season rolls around again, I have to think - what's next? What comes after 5BDXCC? It's a good question.

I still have a few other bands to add. On 17m, I have 87/87 confirmations, so that's likely next. It will be easier now that I've identified the problem with my WARC dipole. ON 12m, I have 73/73 confirmations is not that far behind, although old Sol is not likely to be active enough to sustain much propagation on that band for a few years.

160m seems less likely, where I have 42/41 confirmations. Given how hard 80m was, it may take quite a while to add many more entities there.

The DXCC challenge is still unclaimed. I have 835 current credits, and my unapplied LoTW confirmations will bring me up to 1125, if I applied them all. Plus at least five more QSLs I'll submit this year could get me all the way to 1130. I've decided a couple of years ago not to push for this too early. The 80m DXCC submission this year, plus all the band endorsements should get me over 950 credits. I'll make it over the 1000 credit requirement as soon as I complete another band.

And, of course, there's the DXCC Honor Roll. At the moment, I have 259 current confirmations, which puts be 80 away from the 339 total. And 71 away from the 330 required to make Honor Roll.  That may take quiet a while. I have two cards that I'll submit this year, and there's a dozen more entities I've worked that I need to obtain confirmations from.

Naturally, some of these remaining entities are increasingly rare. The good news is there are several exciting DXpeditions this year. I'll have to make plans to work them when I can.

So, yeah, still a lot of challenges left in DXCC.

Monday, September 4, 2017

Back in the Harness Again

Yours truly on the tower.
When I moved back from Floyd County a couple of years ago, I did a tower inspection. When I got to the top section joint, about 10 feet above the roofline, I lost my nerve. I checked the bolts, then came slowly down the tower. I haven't climbed since. Until today.

I really had to. All the antennas on the top of the tower show signs of being messed up. Mission today was the WARC dipole. While still resonant on 12m, 17m showed no match, and 30m was way out of band.

I took the ends of the dipole loose, you can see two of the traps around my foot level on the tower. Then the climb to the 44 foot level of the tower. The center of the dipole is a NEMA box U-bolted to the tower leg.

Being up there is a little unnerving at first. You try to stay as still as possible, because each move causes the tower to sway.

Of course, as soon as I got up there, I find I don't have a screwdriver. This is why you always use a ground crew. My daughter Lauren did an excellent job in this department.

With the lid to the NEMA box off, took off the U-bolt, and lowered the dipole to the bottom of the tower.

Once back on the ground, a quick inspection showed what was wrong. One of the 17m traps had a clear open, and it wasn't something that was easily fixed. After 12  years on the tower, the shield braid from the trap coax had disintegrated. The trap needs to be rebuilt. It's companion doesn't look much better. In the interest of keeping them symmetrical, I decided to rebuild both the 17m traps. The 12m traps are a couple of years younger, and look to be in good shape.

After I get the traps rebuilt, it will be back up the tower to re-install. And then I need to lower the A3S down so I can check out the driven element -- figure out why I've lost resonance on 15m and 40m is so messed up.