Fixing the K2/100, Again

D16 and D17, plugged into machined socket pins.

About a year and a half ago, I wrote about repairing my K2/100. Part of the fix involved replacing diodes D16 and D17 on the KPA100.

The same week I bricked my K3/100, I found the K2/100 was acting up. I was going to grab it in case I needed to send the bricked K3 back to Elecraft.

But, before I did that, I spent part of an evening trying to work some of the W1AW-portable operations. I didn't have a lot of luck. The power output seemed erratic on some bands, and on others, the automatic antenna tuner couldn't seem to find a match.

Seems to me I'd seen this behavior before -- when the SWR bridge diodes, D16 and D17, had undergone a soft failure. I figured that if this was going to be a regular occurrence, I ought to make the job easier.

I found an old machined-pin IC socket and carefully clipped away the plastic to reveal four individual pins. Actually, it was more like six pins, since I dropped one and couldn't find it under my desk. And another one I hopelessly bent. Fortunately, these things come packaged with fourteen to sixteen pins at a time, so I had plenty of spares.

A bit of work with a screw and nut driver released the KPA100 board from the heatsink. Pulling the old diodes from the board is a bit of a delicate operation, since you want to be carefully not to mess up the board traces. However, with the socket pins, this is the last time you'll do this.

Soldering the socket pins in place is one of those operations that would be easier with four hands. Even holding the board in a small Panavise, I needed one hand to hold the machine pin with pliers, one hand to hold the soldering iron, and one more hand to hold the solder. That's one more hand than God gave me, but somehow I managed.

Once the pins are in place, it is a simple matter to trim the diode leads and bend them down to fit the socket pins. I had ample spares from my earlier purchase.

I checked the diodes with my DVM. (Oh, I should mention that I discovered my 20 year old Radio Shack DVM bit the dust. Apparently one of the AA batteries inside managed to get enough corrosive goo on the circuit board to render it irreparable. So, I had to go out and buy another DVM. It would have been nice to know this before the last hamfest, as these types of devices can easily be had for a few dollars. As I was, I bought a cheap unit at the local Home Depot for about $20. More than I wanted to spend, but I had it in my hands immediately.) These diodes didn't show any obvious odd behavior. The forward voltage was a little off, and the reverse voltage was at the limit, just like you'd expect.

Nevertheless, I put new diodes in and ran the calibration procedure for the SWR bridge. Not having a dummy load handy (something else I left at my other QTH), I used a 40m antenna that was a pretty good match. After calibration, the K2/100 seemed to work as expected.

I'm surprised how sensitive these diodes appear to be to static discharges. I'm going to have to make sure I keep the rig antenna grounded when I'm not around.

Honey, I Bricked My K3

K3/100 in the operating position

A couple of weekends ago, I noticed that Elecraft had updated the release firmware for the K3 back in February. I'm not much for trying beta firmware, but I try to keep up to date. 

So, I fired up the old Elecraft K3 Utility and set it to go. I did not realize at that moment that I was to undergo a multi-day ordeal. 

MCU load went OK, but then it decided to upload the FPF. It kept getting stuck on the FPF. I figured it was just a glitch, so I tried it a half-dozen times. Each time, it would fail on the FPF load.

Of course, this left the K3 unusable. Without the front panel firmware, there's no front panel. My K3 was just about as useful as a brick.

Frantic e-mail to the elecraft email list brought several helpful responses, the most helpful was from Elecraft support.

Unfortunately, it would be a couple of days before I could try their suggestions, as I had to leave my Floyd County QTH for Gwinnett County. 

Three days later, I was able to put my full efforts into the solution. Apparently, I had tried to load the firmware with an old version of the K3 Utility. While Elecraft says this won't work, what they don't tell you is that it breaks your K3 in a weird way. 

That was easy enough to figure out. However, my problem was that even after I updated the utility, it wouldn't load the firmware, either.

At some point, someone suggested I try to load the old firmware. Well, doing that is not straightforward. You see, you have to go to your firmware download directory and remove all the files that weren't in the previous firmware. That's not obvious.  Eventually, I figured out that the FPF firmware hadn't changed -- only the MCU and DSP firmware were updated. Removing those files, I attempted a full download.

Voila! It worked. My K3 is un-bricked. I was now back to firmware 4.67. Now to try the update.

Instead of selecting the option to download all firmware, I chose the option of only downloading the updated firmware. That way, it wouldn't have to try to re-load the existing FPF, saving a bit of time.

Of course, it upgraded without a hitch. Goes to show you need to use the right tool. And follow directions -- the Elecraft instructions stated you need to use the latest utility. I should have checked instead of just assuming.

W1AW Centennial Operation - The Way To 9B WAS

OK, it took me a month to catch on. I read about the ARRL Centennial celebration. If you haven't heard about it, take a moment to check out the link. What you want to see is the Centennial QSO Party.

I'll wait.

Now, I didn't get very excited about the Centennial Points Challenge. I'm sure I'll work a few points this year just as a natural side effect of operating in contests and other events throughout the year. When I read about the W1AW portable operations from all fifty states (plus US territories), I didn't get all excited either. After all, I already have 6-band WAS. It took the LoTW and many years of work to complete that, doing mostly contest operation, so I didn't make the connection at first.

The W1AW portable operations make it easy to achieve 9-band WAS.

I think it hit me one night when I was looking at spots for FT5ZM. (Great DXpedition, if you didn't manage to work them, well, it wasn't their fault...) I saw spots for W1AW-portable. Some of them were on 30, 17 and 12m.

Now, I said I have 6-band WAS. That's because there are no contests on 30, 17 and 12m. I do operate there, but it's been mostly DXing. I do a little casual style operating with USA stations, but many of these rag chewers don't tend to QSL via LoTW.

I then made the connection -- these highly visible W1AW-portable operations are the perfect way to fill in all the holes in your LoTW WAS confirmations. All of the W1AW-portable contacts will be confirmed on LoTW. They will operate from each state twice throughout the year for an entire week, being on the air virtually all the time. Perfect.

Since then, I've been sneaking into the shack working W1AW-portable on all the bands that I need. I have two award accounts, one for Floyd County and one for the QTH in Gwinnett, so I have a chance to fill in the holes for each.

Don't have WAS? Or need WAS on a hard band like 80m, 15m or the WARC bands? This is your chance. Good luck.

CW Op -- When Did That Happen?

I came to a realization late this fall. I'm a CW contest operator now. I'm not sure how that happened.

As I recounted in my Novice story, I started off with CW, since that was all Novices were allowed to operate. Even after I upgraded to General, I still operated mostly CW.

When I started radio contesting in 1986, I did both CW and Phone contests at first. Phone contesting brought more success. By 1990, I had pretty much given up on CW contests.

In 1996, something happened. Bill Fisher (then KM9P, later W4AN and now, unfortunately a silent key) was asking people to join teams for the North American QSO Party (NAQP) for the newly formed South East Contest Club (SECC). While i hadn't operated a CW contest in years, I wanted to participate in SECC activities. So, I volunteered to join in.

I've misplaced my write-up for that contest effort, but I won't forget it. I moved into the house in Gwinnett county late in 1994. In January 1996, I was still finishing rooms in the basement, and did not have any ham equipment set up.

My 1996 NAQP CW effort was a hastily improvised affair. I hung a 125 foot doublet fed with open wire, between the railing of the deck and a tree in the back yard. It was probably all of 15 feet in the air at its highest. I set up my venerable Kenwood TS-430S on a lunchroom table, with a  Murch UT-2000A antenna tuner. The setup was in an unfinished basement with no heat, so I put on warm clothes and wrapped myself in a blanket.

Ten hours of operating later, I had all of 120 QSOs in the log, and I was cold despite the blanket. Many of the operators were going far, far too fast for me, and it was real work to get them into the log. Despite this, I was pretty pleased with my score. Still, there was plenty of room for improvement.

Real contest CW operators don't operate as I did then, scribbling everything down on paper. They copy in their head. The first revolution was to throw the pencil away. At first, I copied code by typing notes into the computer. I would use two computers, one for logging, and one with a TextEdit application running. A year and a half later, I had progressed to the point where I could copy standard contest exchanges in my head. Well, at least long enough to type them into the computer and log them. That contest, the NAQP CW Summer of 1997, was the first contest I would consider "fun" instead of "work."

It would take about five more years before I could copy most of the high-speed contest code, sent around 30 words per minute (wpm).

The second revolution came in sending. Until 2002, I send everything by hand using a keyer. Then I hooked up a simple little circuit that would allow my logging computer to send the code. What a God-send! While I might be able to copy code at 30 wpm in my head, I could only send about 20-25 wpm, and sometimes not that well. The computer, on the other hand, would send flawless code, and could do so at 28-30 wpm.

At this point, I could receive and send contest CW at nearly 30 wpm. That's basic. But, there's still more. Just receiving and sending isn't enough -- you have to know what to send in response to what you receive. You have to know how to pick up calls the first time when you tune up on them would S & P. You have to know how to sort out the pile when three or four people try to answer your CQ.

Slowly, I accumulated some operating skills. In 2005, I was recruited to be a CW operator for a large 9-transmitter Field Day operation. I ended operating 15m, 80m and 10m CW. What fun! I had such a blast that I did it again the next year.

The hardest skill to acquire is knowing how to run -- how to answer when multiple people are calling in response to your CQ. You can't know what to do without lots of practice. And, with low power and mediocre antennas, it's hard to get a lot of practice. All the time I've spend operating with the NQ4I multi-multi team has slowly paid off.

I've finally reached the point where I feel pretty confident on CW, even calling CQ. During the NAQP CW recently, I watched as the last 10 rate meter peaked at 264 / hour. That doesn't happen often, but it makes me smile when it does.

Straight Key Night 2014

Homebrew Transmitter and Receiver, ready for another
go at Straight Key Night in 2014

Last year, Straight Key Night (SKN) was kind of a bust for me. As I wrote then, I ran into trouble trying to key my 35+ year old electronic keyer to key the 40m "Novice" rig. This year, I got to operate SKN with no problems.

Despite having an entire year to figure it out, I left fixing the keyer to the last minute. Back in the summer, I had modified the keyer to use a 2N3906 to key the gate of a BS170. However, when I hooked it up to the rig, it wouldn't key -- oscillator problems again. It went back to the project shelf to be figured out later.

At some point, I took the keyer back to Gwinnett county to try to troubleshoot it there. But as fate would have it, I didn't have time to figure it out. Right before Christmas, I brought it back to Floyd county.

A bit of work with the mini-scope proved that the oscillator wasn't firing at all. It took a while until I found the source of the problem: one of the wires to the speed potentiometer had broken off, so the RC circuit was broken. Without it, there's no phase delay, and therefore, no oscillation.

Built in 1979, Mini-MOS keyer provides yeoman service again.

Great! This means I just hook it up to the rig and go right? Wrong. It appeared to work for a few seconds, but then it would continuously key. It was erratic. Troubleshooting it a bit more, and it seemed to work -- the keying signal would get to the gate of the BS170, but not beyond. At one point I thought maybe I had a bad MOSFET, so I pulled the BS170 out. (In the process, I ended up destroying the part - oops)

Pulled a 2N7000 out of the junk box. The 2N7000 and BS170 are pretty much the same part, although the pin-outs are different. Hook it up and it seems to be working great. I can see the keying on the gate on the 'scope, and the transmitter is happy. Unplug the scope probe, put the lid on, and ... it's locking up again.

Hmm. Take the lid off, put the probe on, and it works again. On a hunch, I pulled a 100k resistor out of the junk box and put it across the gate to ground. Working -- even with the probe removed. Ah ha! That's the problem. The gate of the 2N7000 (or BS170) wasn't being pulled back down to ground, so the floating leakage from the 2N3906 was just barely enough to keep it turned on. Adding the scope probe brought in just enough resistance (a few megaohms), to overcome that leakage.

All ready to go. After dining out with a church group on New Year's Eve, I managed to work seven stations all before the ball fell. Of course, I told them that I was cheating, using a 35+ year old keyer instead of a straight key. No one seemed to mind. I did find that my 7061.1 kHz crystal stopped working. Worked one more person on New Year's Day for a total of eight.

A great way to bring in the new year. I guess I'll submit mine as a check log....

Audio Games

Recently, I was trying to explain amateur radio contesting to a non-ham friend. "You know what video games are, right?" She gave me a cold look, as if to say, of course I know what video games are. "Video games," I continued, "are games you play with your eyes and fingers. Contesting is a game you play with your ears and fingers."

In a nutshell, that's pretty much it. Described that way, however, doesn't tell you a whole lot. Video games described this way doesn't tell you much, either. The reality is that every game worth playing has strategy.

To understand radio contesting, you have to understand the nature of radio. Most contests take place in what we call the "short-wave" or HF (High Frequency) bands. There are six bands in this spectrum, all identified by their (approximate) wavelength.

160, 80 and 40 meters are basically night-time bands. Ever notice that you can't hear far-away AM broadcast stations during the day, but you can at night? That's exactly how 160m is -- open during the darkness hours only. 80m and 40m are the same way, but are open a bit longer before dusk and after dawn.

10 and 15 meters open during the daylight hours, and possibly shortly after dusk -- just the opposite of 160, 80 and 40 meters. During sunspot minima, 10 meters may not open at all, and even 15 meters can be lackadaisical. 20 meters rounds out the bunch. It's mostly a daylight band, but during sunspot maxima can be open round the clock.

The basic idea of a contest is to make as many contacts (what hams call a QSO or "Q") in a defined period of time. Each contact involves the exchange of call signs ( unique identifiers assigned to each station by their governing agency ) and one or more other pieces of information. Typically, it's pretty simple - like a signal report and a state, province, country or zone identifier, maybe a name.

A game isn't fun if you don't keep score. Most contests use a two-factor scoring method. First, you get a certain number of points per contact, depending on the contest. You can't contact the same station more than once, or at least once per band. Those duplicate contacts don't count for any points.

Next, each contest defines a set of geographic areas that count as "multipliers." These could be states, provinces, ARRL sections, ARRL DXCC entities, or zones. In some contests, the multipliers count for each band.

The final score, then, is the number of contact points times the number of multipliers. As you can see, it's important to have a large number of both contacts and multipliers (or "mults") in order to make a high score.

There are two ways to make contacts in a contest. You can call CQ -- for the old morse-code pro-sign for soliciting for contacts -- and get people to call you. This is called "running." The alternative is to tune the band and look for others calling CQ. This is called Search and Pounce, or "S & P." Generally, you can make a lot more contact points running than you can doing S & P, provided you can attract people to call you. The disadvantage of running is that you may miss some rarer mults who are also running. The best contesters use a mixture of both techniques - periods of running punctuated with S & P.

Add to this mix the need to get multipliers on multiple bands, the varying propagation during the day, night, by season of year and the 11-year sunspot cycle, plus the unpredictable nature of the sun, and you have the recipe for a big challenge.

Plus, a contest can really help build your confirmation totals in pursuit of any number of awards -- like ARRL Worked All States, ARRL DX Century Club, CQ Worked All Zones, CQ WPX as well as others.

There's something satisfying to calling CQ and running a rate of 100 contacts per hour for even a few minutes, or to tune across a band at an oddball time and be the only one to catch a rare multiplier. You can run the same contest a dozen times and never experience the same situation. It never grows old.

160m / 80m / 40m Inverted-L

Can you see it? I can't either. The black wire in the middle
ascends into the tree, but the traps are virtually invisible

The 160m Inverted-L went up nearly a year ago. Six months ago, I added a trap for 80m, making it an 160m / 80m Inverted-L. At that time, it seemed like a good idea to add a 40m trap. It's taken me a few months to do this.

I used CocoaNEC 2.0 to model the trapped inverted-L. With multiple traps, there's lots of interaction in the antenna segment lengths. More than you'd think, since the trap resonant frequencies are well outside the operating frequencies of the antenna. This means that the trap impedance, while high, doesn't completely cut off the flow of current in the rest of the antenna. This means the 160m segment length affects 40 and 80m and vice versa.

My model showed the 40m segment would be about 32.5 feet, the segment between traps would be about 3.6 feet and the rest of the antenna would be about 69 feet. The problem with this model is that it uses NEC 2 -- which assumes a perfect ground, so the real antenna different. My approach was to insert the 40m trap at about 34 feet, and then slowly trim to a resonance in the band. Then I'd trim the segment between traps, and finally the 160m segment.

Comparison of 40m (left) and 80m (right) traps. Note the
turns on the 40m trap are a bit loose

40m trap was built for 6.7 MHz. This required about 7 turns of wire on my 3" schedule 20 PVC pipe form and a 100 pF capacitor.  Same technique was used to trim the trap -- the Heathkit gate-dip oscillator.

Trap went in at 34' and after three trims it was a 29' 7". A couple of trips and the 80m segment was 7' 4" long. Everything looked good.

Note that the between traps segment is considerably longer than the model. Could very well be the traps I built are not exactly the same as what I modeled, in addition to the lossy ground effects. I think the modeling work is useful, though, because it has gotten me in the ballpark.

Another view. 40m trap uses 100 pF, 80m trap uses 200 pF.

Last trip was 4 feet off the 160m segment, for a total of 63'. Hmm. 40m is now resonating just above the band. Drat.

I'm not sure if maybe the turns on the trap may have loosened when I raised it last, or if the 160m trim caused the shift. I ran out of daylight to test it. However, the antenna still works pretty well. I've been running this antenna on all bands through the KAT3 antenna tuner, and it is pretty effective on the designed bands, as well as on 30, 17, 12, 10 and 6m. It works ok on 20 and 15m, but I always feel I'm competing with tribanders and other beams there.

Hasn't been a whole lot of activity on 80m this fall -- I think part of it is because everyone is enjoying the conditions on 10 and 12m. Hope to see more activity as the nights lengthen, so I can work some more DXCC entities there. I also want to try this puppy in the ARRL 160m contest.

This antenna really worked well during SS CW. I used it on all bands through a tuner. Although, for domestic contests, the 80/40m dipole works much better.