Personal Perspectives on the Bruce Kelley Memorial QSO Party

It’s that time of year again – time for the annual Bruce Kelley 1929 QSO Party. This unique event, sponsored by the Antique Wireless Association, is like an “activity period” for use of transmitters built around circuits published in or before the year 1929. Many say it is meant to be a fun event, not a contest.

I have a 1929 TNT transmitter I built in 2011 after long time friend Ron, N4GJV mentioned the Bruce Kelley party to me. I had always been fascinated by the unique appearance of 1920s transmitters. Learning of this annual operating event compelled me to build one. Every year at this time, I struggle trying to decide whether to participate or not. I took part in 2013 and 2015 under my own call sign, taking first place both times. In 2016 I was given the special honor of operating under club call sign W2ICE, which was Bruce Kelley’s call sign. I haven’t participated since then. The Bruce Kelley is one of those events I want to love, but in reality my relationship with it is more of a love-hate thing. To understand why, I have to acknowledge that I could be a poster child for adults on the autism spectrum. I am very seriously impacted in several ways, the effects of which are evident in every aspect of life.

They call it a party, but what it is depends on who you talk to. For some it is a very informal event, a time to fire up the really old rigs and make a few contacts for fun. For others it is a contest and they are out to win. Clearly I fall into the latter category. It’s like the old Pringles commercials – bet you can’t eat just one. Nope, I eat the whole darn can of ’em! I find it impossible to just have fun and not make it about competing. Competing is the fun. Well, that and the warm glow of a UX-210 filament filling the shack. I suppose by nature I am a very competitive person. This is stifled everywhere else in life, so it comes out in ham radio. Ham radio is that one special area in which I feel confident and comfortable, whereas everything else seems alien. This is autism clearly showing itself. It would also be fair to say that many on-air aspects of ham radio have not been inviting or have been downright uncomfortable because of my life challenges. Conversational QSOs and ragchewing are pretty much out. Contesting, being a facet of the hobby that is generally quite comfortable, has gotten into my blood and I always feel it pulling at me. Whatever you call it, results of the Bruce Kelley event are published, and a plaque is presented to the station making the most contacts. To me, that makes it pretty cut and dried – whatever the name, it’s a contest. I have tried to operate casually, but competitive instinct takes over, pushing good sense aside.

On the face of it, you’d think that wouldn’t be a problem. I am a contester and to me the Bruce Kelley event is a contest. So what’s the deal here? Well, for for one thing the exchange is very long: signal report, name, state, transmitter type and year, power level. That is much longer than most contest exchanges and gets into my discomfort zone. This is compounded by it being a low power event. I might be ousted from the ranks of “1929” builders and operators for admitting this, but I am not normally a QRP operator. I stress about whether I’m going to be copied when running low power. While sending the long Bruce Kelley exchange, I tense up and break out in a sweat. With low power and the long exchange, there is a very real possibility that it won’t be copied entirely and repeats will be needed; additionally there is always the risk of “losing” a QSO that can’t be competed because conditions changed, something I just have a hard time with. Overall, operating in this contest is difficult and exhausting to me. Yet once I start, the contester in me takes over and I am there for the duration. I would be much more comfortable if the exchange were short, say signal report and state. But that would ruin the event for the majority of participants. My perception is that many “29” operators are folks who enjoy a good ragchew. There is nothing wrong wit that. I admire them and wish it were that way for me. Furthermore, most who participate in this event want to know the other operator’s name and what transmitter they are using. To most, that is part of the fun. To me, it is torture. I too am very interested in knowing what the other guy is using for a rig and so on, but getting that information over the air while operating QRP is not a comfortable thing.

There are good reasons why this is a low power event. For one, it is far more difficult, dangerous and costly to build a high power transmitter conforming to 1929 design. If high power were allowed, low power stations would have no chance to be competitive, and many would be priced out of the game. Even if low power is stressful for me, I wouldn’t want that to change for this event. One of the things that make it special is that the playing field is maintained such that those on a modest budget can compete. I like that. There is another good reason for keeping this a low power event. The old rigs don’t sound like modern ones. They have chirp, clicks, buzz and so on. This increases the risk of interfering with other users of the bands. Low power helps mitigate that risk. Overall, while I am attracted to this unique operating event, I must acknowledge is wasn’t crafted with the likes of me in mind. Which is fine, of course.

Another factor which has made this event less enjoyable for me has been use of a straight key. Back when I participated, this was not not mandated by the event rules, but many participants feel using anything else is not in the spirit of the event. Now the rules clearly state hand keys or Vibroplex type keys should be used. Personally I love the smell of ozone as the high keying voltage and current sparks at the key contacts! Ah, “real” radio! Using a straight key is consistent with the spirit and reality of 1929. But I have some issues with my arm, compounded by surgery on it a few years ago. Even just pounding out one or two QSOs on the straight key makes my arm ache. After my last participation in the Bruce Kelley party, my arm hurt for weeks. I even consulted a doctor to see if I had done any lasting damage. I decided I would not be doing it that way again, and built a keyer which can handle the high keying voltage and current of these vintage rigs. When I mentioned this in one of the forums, there was something of a small storm of controversy regarding use of anything other than a straight key. This has been a discouraging factor to me since that time.

So, here we are at that time of year. The Bruce Kelley 1929 QSO Party kicks off in just over 48 hours. The TNT is set up and tested. It is connected to the new keyer. But I have yet to decide whether I will operate or move the TNT back into its usual home, under an acrylic cover in my living room. It does make an interesting display piece and I enjoy seeing it every day, but it would be nice to use it on the air a bit more. Edit: Just over 12 hours to go and the deciding factor is the rule on using hand keys. I’m out. The rig goes back to its point of display as an ornament.

2200m Variometer Failure

On the morning of January 15 I was nearing the end of a 72 hour test of the JT9 submodes (JT9-10, JT9-5, JT9-2, JT9-1) on 136.395 kHz. The transmitter had been running 87% duty cycle for two days and as far as I knew all had been well. On this morning I checked in on things when I got up just before sunrise. It was running as expected with the waveforms on the ScopeMatch looking normal. I went about some morning chores and came back about 20 minutes later to check again. The transmitter was still running but the antenna was far off resonance. Minor changes are common but this was more than a minor change. I knew something was very wrong.

Loading coil and variometer assembly. The outer coil is 2 mH. The inner coil is about 180 uH and is driven up and down by a motor and threaded nylon rod. The adjustment range is approximately 2.3 to 2.5 mH total. This is more than sufficient to resonate the antenna anywhere in the 2200 meter band and allow for changes in weather conditions.

I quickly shut down the transmitter, grabbed my binoculars and went to the window to inspect the antenna. All wires were up and intact. I then hastily bundled up and went outside to check the loading coil / variometer. It didn’t take long to realize where the trouble was. When I removed the cover from the assembly housing, acrid smoke came billowing out and I could feel heat radiating from somewhere inside. This was not good! Since the smoke was so thick and presumably toxic, I could not do a full inspection until things had aired out a while.

2200m (left) and 630m (right) variometer enclosures. The blue drum is not tall enough to fully enclose the 2200m unit, hence the upside down bucket which is part of the lid assembly.

Upon subsequent inspection I found the bottom of the moving inner coil badly damaged. I can only guess as to what happened. Careful inspection of the following pictures will reveal something of the construction. There was a wire (12 AWG solid, insulated) running down the length of the form on the inside. This provides connection from the bottom of the inner coil to a a terminal at the top of the coil form which is jumpered to the top of the large outer coil. At both ends, the method of feeding through the form was a 18-8 stainless machine screw with washers and nuts as needed. On the inside the ring lug on the wire was between the head of the machine screw and the coil form. Stainless hardware may not have been an optimal choice. It stays clean practically forever but it has poor electrical properties. I had assumed it would be fine with the expected 2 amps or so of low frequency RF current.

What I suspect happened is that over time, probably aided by thermal expansion and contraction cycles of the PVC form, the hardware became loose on that bottom connection. As it began to loosen slightly, resistance of the connections may have increased somewhat, leading to more heat being generated. This may in turn have led to some slight softening of the PVC, allowing pressure on the connections to relax even more. I believe eventually it became so loose there was arcing which produced extreme heat in a localized area, eventually leading to the damage.

Before disassembly, some damage can be seen at the lower end of the inner coil.
After removing the inner coil assembly, the extent of damage is more apparent.
With the coil removed from the base plate there is more evidence the machine screw was the source of the problem. All of the damage centers around it. The wire inside is badly heat damaged, and the PVC form has either been on fire or has suffered damage from arcing (or both).

In hindsight, there may have been two warning signs that something was not right. If these were signs of failure in progress, things had been going south for some time. About two or three weeks prior to this incident I had noticed that when I was transmitting I would sometimes see “fuzz” appearing on both sides of my signal when viewed on the waterfall of my SDR receiver. It usually lasted only for several seconds, then cleared up. I did wonder about arcing, but the ScopeMatch looked perfectly normal. I put it down to just another artifact of severe receiver overload. It’s not as though my signal ever looked clean in the local receiver! There was always plenty of junk, no doubt worsened by the use of back to back diodes across the receiver front end to prevent damage from my own transmissions. But this particular “fuzz” phenomenon was something I hadn’t recalled seeing previously.

The second possible warning sign came 24 hours prior to discovery of the failure. On that morning resonance suddenly “jumped” higher in frequency. It wasn’t a big change, but was something I hadn’t seen before in benign weather conditions. Re-resonating took care of it but about an hour later it “jumped” back to the original resonance condition and needed to be adjusted again. This unexplained behavior should have been a warning that something was not right.

Much of what I think I know about this failure is speculation based on inspection after the fact. My theory seems further supported by the fact that the other stainless machine screws passing through this form had all loosened considerably. I know they were tight when it was built, but I was able to remove them using just my fingers. I will never know for sure exactly what happened, but the new inner coil will be designed to avoid the suspected failure scenario. If it fails again, I will have to reexamine my theories!

Mowable Temporary Cables

What? Mowable cables? That doesn’t make any sense! Let me explain. Throughout my nearly four decades exploring radio, I have often had occasion to run a “temporary” cable to some antenna. Usually these end up laying on the ground where they quickly become a nuisance, having to be moved every time the grass needs to be cut. This often continues for some time. After all, in a ham radio sense the definition of temporary is “anything expected to be in service for less than the life expectancy of the operator”. About year ago I had a sudden explosion of “temporary” cables. I needed to run coax and a variometer control cable to my new 2200 and 630 meter transmitting antenna, as well as coax to a receiving antenna for those bands in another location. These were put down just after the last lawn mowing of the season, but were at risk of damage from the snowblower as I kept a path cleared to the transmitting antenna during the winter. This summer they have been a constant source of irritation as I had to move them every time I mowed the grass.

Since I still can’t afford good coax and conduit to do this job in a permanent (meaning less irritating) fashion, something had to be done. One obvious solution is to dig a shallow trench and lay the cable in it — with our without burying afterward. This tends to be a lot of work and it’s messy, disturbing the grass (uh, I mean the weeds) and leaving dirt strewn all over. I was looking for a cleaner and, hopefully, easier method. One morning about 2 AM it came to me. I sat bolt upright in bed, sending Boo (the cat, who had been asleep on my chest) fleeing for cover. Who said you had to dig a trench? I have soft, sandy soil. Surely one could press a trench into the ground without the mess. It just might be easier, too. The following series of pictures depict the process, which worked very well.

Step One: Mark a line. Drive in stakes at each end and at any locations along the run where a bend is required. Run string (or small wire) from end to end, then spray paint a line on the ground along it.

Details of the string (wire) and painted line at a bend point.

Step Two: Hammer a slot into the ground. I used an 8″ x 8″ dirt tamper and a 10″ length of 1.6″ OD steel pipe. Lay the pipe on the painted line and hammer it in until its top is flush with the surface of the soil. In my soil this takes two to three blows, and the flat plate of the tamper makes it easy to know when you’ve reached the correct depth. This photo shows the pipe in place before being driven into the soil.

Here is a photo showing results after the pipe has been driven flush with the soil. To continue I simply pull out the pipe and move it forward 9 inches (just a bit less than the length of the pipe), then drive it into the soil again. The process moves along quite quickly.

Step Three: Lay the cable into the trench. I make 15 to 20 feet of trench at a time, then lay cable into it, then do another section of trench.

The completed job. There is no messy strewing of dirt, the paint line has virtually vanished, and the cable can barely be seen if one is not standing very close to it or directly in line with it. The top o of the cable is 3/4″ to 1″ below grade, so it is out of danger from the mower. Of course it is still subject to damage from any number of things, but with temporary, zero cost cable runs that is usually a fact of life.

First USA to Europe Amateur Radio 2200 Meter QSO

It was early morning on the 28th day of March, 2018. Most people were sound asleep but not me. I was in my ham shack, hands trembling, heart pounding as I typed a few letters and numbers into my logging program. I could barely breathe. I had just completed one of the most exciting QSOs of my nearly four decades chasing DX. This single QSO cost more money and time than any other I had ever made. It was a QSO with England. You may wonder what is so exciting about that when any ham with five watts and a piece of wire can contact England from Maine. Well, this was special because we did it on the 2200 meter band. It was the first amateur radio USA to Europe QSO on what is, for us, a new band. This was no easy feat. It required months of station building and four nights just to complete the QSO. Some would call it a ridiculous folly and see no sense at all in it. But to me this is the true spirit of amateur radio, finding a way to communicate against the odds, adapting equipment and technique to accomplish the desired result. It is man and his machine against nature, determined to succeed under the most difficult circumstances.

The 2200 meter band allocation is 135.7 to 137.8 kilohertz in the long wave part of the radio spectrum known as LF or low frequency. In some ways this goes back to amateur radio’s early roots on 1750 meters, but it had been more than 100 years since U.S. amateurs were allowed to transmit in this part of the radio spectrum. These frequencies are not easy! Normal size antennas would be huge. A half wave dipole would be 3400 feet long; a quarter wave vertical towering to a height of 1700 feet. Natural and man made noise tend to be very high in this part of the radio spectrum and ionospheric propagation is feeble compared to the short waves. On top of that, we are only permitted to run one watt effective isotropic radiated power (EIRP). That is flea power compared to what we can use on most any of our higher frequency allocations! By comparison, when I was doing EME (moonbounce) on the two meter band I was legally running about 450,000 watts EIRP. But ham radio DXers who like a good challenge can be a very determined lot. The greater the challenge, the greater the reward.

I became interested in 2200 meters in late 2016 after the local club asked me to prepare a report on this and the 630 meter band, which were expected to soon be opened for amateur radio use in the U.S. At that time the only way to legally transmit on either band was to get a Part 5 FCC license under the experimental radio service. One could almost write one’s own ticket on power limits and frequency allocations but this wasn’t amateur radio. I did apply for and was granted a Part 5 license but never used it since FCC opened these new bands to amateurs just as I was getting a station put together. I found receiving on 630 meters to be relatively easy, if somewhat plagued by noise and available antennas. But 2200 meters was a very different thing. It took weeks of experimentation and testing to detect the first trace of signal on this band. Many weeks later after more trial and error I was rewarded with my first reception of a ham radio signal from Europe on the band when DC0DX appeared in my WSPR decodes. I confess it was then that I first started to dream of someday making a two way QSO across the Atlantic on long wave.

I thought I had plenty of time to build a station, since the FCC process on opening these bands had been dragging on for years. But in the Spring of 2017 the announcement came that we would get these new bands in a few months! Now the race was on. I frantically began building transmitting apparatus. I didn’t quite make it for opening day in October but I was on the band a few weeks later. Early amplifiers were plagued by budget shortfalls and poor performance. By mid February, 2018 I had managed to achieve 0.5 watt EIRP, just three decibels below the legal limit. The flood gates opened and to my amazement I started receiving numerous WSPR decodes from European stations. Wow!

I believed a two way trans-Atlantic QSO was in my future but was not sure when. I was eager for an attempt but still very much struggling with equipment and budget. I was hearing stations from Europe. Stations from Europe were hearing me. But for the most part, those who heard me did not have transmitting capability or not sufficient to reach across the Atlantic. The best bet would seem to be 2E0ILY. We had conducted tests earlier in the season and I could often copy his JT9 beacon. Chris could occasionally copy my WSPR signal but not at sufficient strength for JT9 to be viable. I knew there were ways to get it done, but this would take several nights. I was hesitant to ask anyone to commit such effort and time to a QSO.

As the relatively quiet season was drawing to an end I realized another season is never guaranteed for any number of reasons. I had given the matter considerable thought. There were no practical digital modes which would work with the low signal levels involved. Two old school modes came to mind: QRSS and DFCW. Both are very slow, trading time for weak signal detection capability. QRSS is extremely slow CW, so slow in fact that it can only be copied by reading it off a computer screen. In this case, a speed of QRSS60 would be best, meaning that each dot would be 60 seconds in duration. A dash is three times as long, just as in normal CW. This mode requires nothing special for equipment, as it uses on/off keying of a carrier and is fairly tolerant of frequency drift. But, the shortest element, the dot, sets the achievable signal to noise ratio. There is no advantage gained from the dashes being three times as long, so it is essentially time wasted. Time is valuable, as signal fading means you have a limited amount of time to copy the message. DFCW, or dual frequency CW is an offshoot of QRSS in which dots and dashes are the same length but sent on slightly different frequencies so that one may be differentiated from the other. This saves considerable time with no reduction in signal to noise ratio but requires more complex transmitter keying and reasonably tight frequency stability. In a typical DFCW60 transmission, the dot to dash frequency shift is a small fraction of a hertz. Transmitter and receiver drift must be held to less than this in order to avoid dot-dash ambiguity at the receiving end. It would take about an hour to send two call signs at DFCW60 speed. It was now late March. Clearly there would not be enough common darkness between Maine and any part of Europe to allow a QSO to be completed in a single night at this speed.

It may be useful to consider what is a QSO. These days the term means different things to different people. I came up through the DXing ranks with what is now a somewhat old school definition for a minimum acceptable information exchange to claim a QSO under very weak signal conditions. I still firmly believe in the old way, as we are after all supposed to be communicators. That definition is that each station must receive from the other both call signs, signal report or other piece of information, and acknowledgment. This requires that two transmissions be copied in each direction. Anything less than that does not seem like communication to me, and leaves me with no sense of accomplishment.

It seemed the best way to go about it would be to borrow operating and reporting techniques from EME, modifying procedure slightly to account for the much longer period of time required to send a message on the long waves. In this procedure, the letter O would be used as a signal report to indicate full call signs had been copied; R and O would be used to indicate full call signs plus signal report had been copied; R by itself to indicate call signs, report, and R (as part of R and O) had been copied. As for timing, it seemed sensible to use night by night sequencing. That meant the two stations would take turns transmitting, one going the first night the other the second, alternating back and forth throughout the QSO. It would take a minimum of four nights to complete a QSO, assuming the full message could be copied each night. If it wasn’t, additional nights would be required for repeats. That’s really slow! But it did offer some advantages with the equipment available. In order to achieve the required frequency stability I would have to use my QRP Labs Ultimate 3S beacon transmitter. The U3S is a great piece of gear, but editing messages is tedious. Night by night sequencing would give me all day to change the message for the next night’s transmission! A complete QSO would look like this, where bold indicates my transmissions, italics indicate transmissions from the other station:

2E0ILY N1BUG
N1BUG 2E0ILY O
RO
R

Meaning of the first line is obvious. I am transmitting both call signs. In the second line my QSO partner adds the signal report, O, to let me know he had copied both call signs fully. In the third line I send RO which means I have copied call signs and my report, your report is O. In the last line my QSO partner sends R, meaning I have copied all on my end. When I copy the R the QSO is complete. If a message is not copied, or not enough information is copied, then one continues to transmit the previous message until getting something back which advances the QSO.

I had worked out a viable technique. Now I just needed a QSO partner. Just in time I worked up the courage to ask Chris, 2E0ILY if he would be willing to give it a try. I was very happy when he said he’d have a go at it.

We had decided I would transmit the first night, so I set the U3S to send ‘2E0ILY N1BUG’ over and over during the hours of common darkness between our respective locations. It turned out to be an ugly night in terms of weather. I was getting heavy wet snow squalls. Nothing causes a 2200 meter Marconi antenna (vertical) to go out of resonance any quicker than wet snow! These antennas are electrically short and require huge loading coils to resonate them. They are high impedance antennas and the bandwidth is very narrow. These antennas are prone to changing characteristics on a whim. Every time the snow started, stopped, changed intensity or the amount of snow clinging to the antenna changed, the thing went wandering up or down the band and required retuning for resonance on the operating frequency. Fortunately the variometer at the antenna base was motorized and I could adjust it from the comfort of my transmitter room. But I had to keep a constant vigil, watching antenna resonance and adjusting as needed. I had my finger on the switch for variometer adjustment far more than not. After a while my fingers were getting sore from constantly manipulating the tuning switch. Perhaps I shouldn’t have used a miniature toggle switch there. If you think this was an automated QSO without operator involvement, think again! My presence and diligence at the controls was absolutely vital that night!

Message copied from 2E0ILY on the second night of the QSO (annotated). Note dots on the lower frequency, dashes shifted 0.187 Hz higher. When the signal is this strong, elements tend to bleed together a little but since they are of fixed length it is still very readable.

The next night it was my turn to listen. Due to the extremely slow speed DFCW is copied visually  using software designed for this purpose. Anxiously I stared at the screen. When I wasn’t nervously pacing, that is! I began to see traces of signal, then an odd letter here and there. There was a B, a 2, a Y and I even thought I saw an O but couldn’t be sure. Eventually conditions stabilized and I began to get steady print on the screen. Waiting 60 seconds for a dot or dash to fully paint on the screen can be agonizing. Slowly the elements accumulate and become characters. If you are lucky, propagation holds up long enough to copy the full message. Fortunately, after somewhat of a slow start copy remained solid and I eventually had N1BUG, 2E0ILY and a very nice O painted on my screen! I had copied full call signs and a signal report indicating Chris had got full call signs from me the previous night! We were half way there!

The third night I was transmitting again. Since I knew Chris had already copied full call signs from me, it was not necessary to transmit them at this stage of the QSO. Technically I could have just sent RO repeating throughout the night, but being of the cautious type I decided to include call sign suffixes to provide positive evidence the correct station was being copied. Thus the message I transmitted was ‘ILY BUG RO’. This was a risk as it takes far longer to send than simply ‘RO’ and signal fading can be a huge factor. At least the weather was better and I didn’t have to ride the variometer all night.

Soon it was night four, back to pacing and staring hopefully at the screen. I was especially nervous that night, as I had some strong, drifting interference right on top of Chris! Finally it moved just enough that I could make out ‘BUG ILY R’. There was rapid fading and the dash in the R was much fainter than the rest. Fainter but unmistakably there. I was positive about the R but being the cautious type and realizing this QSO would be an amateur radio first I really wanted to see it more clearly before declaring the QSO complete. The signal faded and nothing was seen for hours. Sunrise at 2E0ILY was fast approaching and I had to make a decision. Was I going to log the QSO or retransmit my RO message the following night in hope of getting better copy of the R on night six? Just before dawn the signal reappeared, very weak. I could barely make out ‘BUG IL’, then the ‘Y’ was quite strong. Given the proximity to sunrise every minute felt like an eternity. Ticking of the clock became offensively loud. It was going to take another four minutes to get an R! Would it hold up that long? Slowly, as the clock ticked and my heart raced, a crystal clear ‘R’ painted on the screen. There were traces of signal for some time after that but nothing  I would call readable, save a stray ‘Y’ that somehow came through well past dawn. So it came to be that shortly after 0600 UTC (1:00 AM local time) on this, the 28th day of March, 2018 I entered this QSO into my station log. We had done it!

QSL card received for this very memorable QSO!

This was an amateur radio first from the U.S. but nothing new in terms of distance on the 2200 meter band. Canadian stations, operating under amateur call signs but otherwise a program similar to our Part 5 licenses, had worked Europe years earlier. Much longer distances had been covered. But for me this was one of the most exciting QSOs of my nearly 40 years as a DXer. It ranks right up there with my first EME QSO, the QSO that put me on the DXCC Honor Roll and several other notable events such as being credited with the first North American two meter auroral E QSO back in 1989. My thanks to Chris, 2E0ILY for his time and patience to make this happen – not to mention the kilowatt hours of electricity expended.

DFCW may be old school but it gets the job done under extremely difficult conditions. DFCW ‘decoding’ is done by the human operator. Deciding what has been copied is not left to computer software which may use assumption or non amateur radio means to fill in things it couldn’t positively make out over the air. DFCW is painfully slow but here we had a very positive over the air exchange of full call signs, reports and acknowledgement without any shortcuts or fudging. I was very pleased with that!

Although this single QSO cost more than any other, this was a low budget operation. Most of the LF station consists of low cost kits and home built gear. Equipment used at my station for this QSO was the QRP Labs Ultimate 3S driving a home built amplifier to 175 watts output. The transmitting antenna was a 90 foot Marconi (vertical) with a top hat consisting of three wires each 100 feet long, spaced five feet apart. Three one inch diameter aluminum spreaders plus triangular wire sections at each end are electrically part of the top loading. This is resonated at the base with an inductance of approximately 2.3 millihenries. Loss resistance at the time was near 100 ohms, resulting in EIRP of 0.5 watt. For receive I used a 30 foot low noise vertical, band pass filter, W1VD preamp, and a modified Softrock Lite II SDR receiver. The amplifier and most of the receive system has been described on my blog and/or web site. There are photos of the antenna and variometer on my web site.

The Diminishing Amateur Radio QSO

I have always gravitated toward DXing and “weak signal” work. I am a very competitive DXer, sometimes contester, and like to push the limits of technology and skill to make difficult QSOs on challenging bands or using challenging propagation modes. I have 297 DXCC entities worked on 160 meters, 125 on 6 meters, 84 on 2 meters. I worked over 600 unique stations on 2 meter EME between the late 1980s and the early 2000s, all on CW.

What is a QSO? It is (or should I say was?) a two-way communication between two amateur radio stations. If we look back at the original definition of the Q signal, QSO means “I can communicate with ______”, where the blank would be the call sign or other identification of a particular station. It made sense to use this Q signal to mean “I have communicated with ______”. They key word is communicate. We are, after all, supposed to be communicators.

So how do we define communication? We had the concept of a “minimum” QSO for many decades. I am speaking here mainly about VHF and up “weak signal” QSOs. Our forefathers, in their wisdom, no doubt in recognition of the fact that we are communicators, realized some standard had to be set on what, at minimum over-the-air information exchange would be acceptable for a QSO to be considered countable for awards, etc. The standard they came up with was that both stations had to copy full call signs, signal report or other piece of information (such as a grid square), and acknowledgment that those things had been received. We had a clear standard definition of the minimum acceptable amount of communication which needed to take place over the air to claim a QSO had taken place. In all the years that I worked meteor scatter and EME on 2 meters and above, I never logged a QSO where I did not copy this information entirely, including both my call sign and that of the other station. Although in any competitive activity we can assume there are a few who bend the rules, I never had the sense that most operators were anything but above board in adhering to the minimum QSO standards. One could find the definition and standards for a minimum QSO widely published.

All of that changed when a new crop of digital modes came on the scene in the early 2000s. First we were introduced to the concept of “deep search”, wherein only about half of the calling station’s call sign need by received over the air for the software to claim a decode. The remaining portion could be obtained by finding the best match in a database of known active call signs stored on the computer of the receiving station. There was no community discussion or voting on this beforehand. One man made a decision that changed everything. The software with this capability was developed and released. It was immediately popular with a multitude of newcomers to EME who found they could now partake of the activity with much smaller stations, and by many of the old guard who were hungry for more QSOs. There were some, myself included, who felt deep search violated the minimum QSO standard and that such QSOs were incomplete, not valid.

Aside from ethical questions, we may ask how reliable is deep search? What if there are several similar call signs in the database, for example? What if the call sign we want is not in the database but a similar one is? I have conducted tests on a number of occasions. To use one as an example, I listened during the 6 meter EME DXpedition VK9CGJ. For some time I listened without deep search enabled. There were no decodes. I then enabled deep search but did not have VK9CGJ or any similar call sign in my database. There were no decodes. Then I added W7GJ to the database and immediately started seeing decodes of W7GJ calling CQ. Then I saw a decode of W7GJ sending me a signal report. This wasn’t possible, as W7GJ was the operator at VK9CGJ. Clearly deep search had misidentified the station because a partial copy matched part of this call sign what was in its database. I Where it got my call sign from I don’t know! I then entered VK9CGJ into the database and started seeing decodes claiming VK9CGJ was answering me and sending a signal report. But wait, it gets better. The signal report wasn’t even in the EME format. In other words, all of these were false decodes. Not just false decodes of a station calling CQ, but false decodes containing QSO information! I had not transmitted at all, so no one should have been calling me. If in fact he was calling me, it could only mean that a false decode had occurred on his end. I have seen similar results in other tests. Similar tests have been carried out by others, with similar results. To me it is very clear deep search makes mistakes. How is it that so many people accept QSOs made with this feature as valid, when the full call sign of the calling station has not been copied over the air? Perhaps almost as disturbing, I have received a number of QSL cards for 2 meter EME QSOs during a period of time when I didn’t even have a 2 meter station. Were these QSOs manufactured by the software?

Later we were introduced to modes which used a single tone (steady carrier) to “communicate” part of the QSO such as signal reports and acknowledgment. Since only a very brief instant of tone recognition was required for the software to claim a decode, this was obviously prone to false positives.

Lately we have another newcomer in the QSO shortcut features. AP (a priori) decoding uses already known information as a QSO progresses to augment decoding. Unfortunately it starts out knowing the receiving station’s own call sign, so this doesn’t need to be copied over the air. The decoder assumes the receiving station’s call sign is in the message unless it gets enough over-the-air evidence to prove otherwise or introduce significant doubt. At this time there would seem to be insufficient evidence on the reliability of this, but I have seen a number of people asking about stations calling them “in the blind” when they haven’t yet transmitted. One has to wonder if these are cases of the decoder assuming their call sign was in the message and then failing to find sufficient evidence to the contrary in a partially received message. Furthermore, on one very popular mode which uses AP decoding, everyone is strongly encouraged never to call someone on the frequency they are transmitting on, but instead to use split frequency. This further muddies the waters. If the usual operating convention were to call on the frequency of the station you want to work, that in itself would offer some clue (though not by any means conclusive) that you are in fact calling that station. But if you stations are calling on random frequencies, this clue is lost. It’s enough to make one wonder if this insistence on using split is just for further obfuscation to hide the truth about AP decoding.

AP decoding with split frequency is ludicrous! Suppose I were to call CQ on CW or SSB. I hear no callers on my frequency but I tune further up the band and hear someone give their call sign along with the some letters that might fit mine, such as “N1” and “U”. It would be ridiculous for me to assume they were calling me. Yet this is exactly what AP decoding does.

I find it very sad that all of this has been accepted with relatively few dissenters. I fail to understand how users of these modes, let alone organizations which issue operating achievement awards can consider such QSOs to be valid. But we are in a new world. For the most part, the definition of a minimum QSO has disappeared, especially the part which talked about full call signs having to be received over the air. Many operators clearly know what these features do and use them anyway. Given the obvious lack of understanding of basic concepts by many, however, it is likely a good number do not understand the shortcuts that are being taken by the decoder. Add to that the fact that we now have a new generation of operators who came into the game in the digital age and know nothing of minimum QSO standards as they existed before. We can clearly see this situation is long since irreversible. The bottom line is that today’s standard for a minimum QSO is closer to mutual detection of signal than a set quantity of over-the-air information exchange. Where will it stop? Are we headed for “QSOs” where only a hint of signal from the other station has been detected but no actual communication has taken place?

Digital modes using these features have largely taken over many aspects of DXing. EME went almost entirely to digital modes many years ago. More recently 6 meter DXing went almost completely digital. HF DXing is taking a strong turn in the same direction, as is VHF contesting. Proponents of digital modes say those who don’t like them should simply continue to use CW or SSB. That sounds reasonable on the face of it, but experience proves there is not enough activity on these modes to sustain a DXer, while at the same time many of the people busily working digital modes say they would rather be doing traditional modes or that they view the digital modes as a necessary evil.

There is perhaps truth to be found in the latter. Long ago EME reached a point where it was not worthwhile to build or maintain a station for the small amount of remaining CW activity. Now the same is becoming true for many other aspects of DXing. The sad fact of the matter is one either accepts the digital modes and the new definition of a minimum QSO or one leaves the DXing pursuit. One cannot be competitive without using the digital modes and most likely cannot find enough activity to justify having a capable station. That is the bottom line. I have been wrestling with this for some time. I have great difficulty taking any satisfaction from QSOs made on digital modes that shortcut the information exchange. Yet there seems to be no other choice if I want to use my VHF/UHF equipment for more than an elaborate home dust collection system.

It isn’t just digital modes that are changing the nature of the QSO. Nearly every day I see people talking about checking the online log of some DXpedition to see if they had a QSO because they didn’t hear enough over the air to know if they made it into the log. How sad. If I don’t hear enough over the air to know the QSO was good, then obviously it was not complete on my end! It doesn’t matter if I am in the DX station’s log or not — the QSO was not valid. But I am clearly in a minority with this opinion.

It seems we have moved away from being communicators, taking pride in building and operating stations capable of real communication. Instead we now look to any kind of mutual signal detection as a basis for claiming a “QSO” and/or award credits. It’s all about the glory with none of the substance. I am not the only one who thinks this is wrong. Many avid DXers having given up and left the hobby altogether. Others barely hang on, wondering if it is really worth it any more.

A Low Drive 2200 Meter Amplifier

Note 25 January 2019: The drain waveform has been corrected and this amp has run many hours at 250W output including some rather high duty cycle mixed WSR-15 / WSPR-2. It seems very reliable at that level. I will revise this post further when I have more time.

Note 12 May 2018: I have discovered this amplifier does not operate with a nominal Class E drain waveform. However that does not change the fact it has performed very well as described in this post. I intend to publish and updated version with corrected waveform at a later date.

While still planning and collecting parts for a high power 2200 meter amplifier I began to wonder if the design I use on 630 meters could be converted and made to work at 2200 meters – and if so, would I have the right parts to build it? Some quick math, assuming linear scaling of component values with frequency, showed that I just might be able to hit the correct values using parts salvaged from a problem ridden dual band amplifier I had given up on. So I set out to build and test a prototype. It took some fine tuning of inductor and capacitor values in the output circuit to get best efficiency and power peak at 137 kHz.

Schematic of the completed amplifier

Initially I used T106-2 cores for the inductors but in order to fit the required number of turns I had to use 24 AWG wire. Heating of the wire was excessive but otherwise the amplifier was showing a lot of promise. I decided to bite the bullet and order some T157-2 cores which would allow using 20 AWG wire. Note: heating of the wire in these inductors was not a surprise. My 630 meter unit does the same, as do several built by others. In the final design, it is possible to run high duty cycle at 100 watts output without a problem. For higher power I recommend a small fan blowing air across L1 and L2. It would probably be OK without the fan but I prefer to err on the side of caution. Capacitors C1 through C4 are made by connecting smaller values in parallel. I had a bunch of .01 uF 630 volt WIMA FKP2 capacitors and some 2000 pf 500 volt silver mica capacitors. These were the only two values needed when using the proper combination in parallel. The DC blocking capacitor is 2 uF, comprised of two 1 uF WIMA MKS4 capacitors in parallel. Initially I used a single 1 uF as in the 630 meter version but I found it was heating up slightly. Going to two of them in parallel resulted in no detectable heating.

The 22200 meter “junk box” amplifier

Construction is similar to the 630 meter amplifier discussed in an earlier post. “islands” were made by grinding away some foil from double sided FR4 material with a rotary tool and diamond bit. The finished amplifier can be driven with one milliwatt (0 dBm), like its 630 meter counterpart. Power output is similar. I measured in excess of 30 watts with a 13 volt supply, 110 watts with 24 volts, and 155 watts with 28 volts. In all cases, efficiency is 87 to 88 per cent. These figures hold over a range of 134 to 140 kHz. Outside that range it beings to roll off rapidly. I have been running mine for the past couple of nights at 28 volts and it seems fine. In the interest of disclosure I did have one FET die during testing but I had not been watching the antenna matching closely enough. Temperatures plummeted from the mid forties to the high single digits during that night of operation, causing the antenna resistance to drop sharply. This caused power output to soar above 200 watts before the FET finally gave up at 3:30 in the morning. I do not consider this a fault of the amplifier. Knowing how 2200 meter antennas are, the operator should have been watching more closely!

Update March 7, 2018: The amplifier has been running perfectly with no additional FET deaths. For more than a week I have been transmitting a combination of WSPR-15 (a good test for any amplifier) and WSPR-2 at 150+ watts output.

Update March 10, 2018: I cranked the voltage up to 30V and have been running the amp at 175 watts output for three nights with high duty cycle WSPR-15 and WSPR-2.

Some Thoughts on 2200 and 630 Meter DX

I came to these bands with a long history of being a 160 meter DX hound. Some of my perceptions and expectations were influenced by that history. Clearly propagation is more challenging at the lower frequencies and being limited to very low EIRP doesn’t help. Nevertheless I was expecting to find a hard core group of low frequency DXers clawing away every night in search of those elusive long distance QSOs. Reality has proven to be very different.

On 160 meters we have a good amount of nightly activity. No matter how late the hour one can find avid DXers CQing away, putting in chair time because with propagation being so variable that is what it takes for success. You have to be there consistently. On 630 Meters that isn’t the case. There is a good amount of nightly WSPR beacon activity which clearly demonstrates the potential for DX QSOs, but very rarely are there human operators behind radios running QSO modes at the times when propagation is there. It seems possible to motivate small numbers to get on and make an effort once in a while, particularly after a very good run of nights on WSPR. This is prone to failure since propagation is so unpredictable. On 2200 meters there is very little activity of any kind, including beacons!

It is, of course, very difficult for most people to be on the air late at night, which is when most of the DX potential exists at lower frequencies. If it isn’t late night at one end of a DX path, chances are it is at the other. The question I keep asking is why do we have a core group of ever present DXers on 160 but not on 630 or 2200 meters? Part of the answer undoubtedly lies in numbers alone. Let’s face it, there are many more stations with 160 meter capability than there are stations with 630 and/or 2200 meter capability. There are a number of immediately evident reasons for the lower number of capable stations. It becomes increasingly challenging to build a capable transmitting antenna system on the lower frequencies. Man made noise tends to be more of a problem and some people live in locations which are hopelessly  noisy. There is a lack of commercial equipment available, so these bands are, for the most part, occupied only by those who build their own. All of these factors contribute to keeping the number of active stations down. Fewer active stations means fewer who have the drive and ability to be on late at night. Numbers clearly play a role in DXing activity. It is actually a rather small percentage of 160 meter operators who are there night after night seeking DX QSOs. Similarly it will be a small percentage on the lower bands but with far lower numbers overall this tends to keep the number of avid DXers below critical mass.

But it probably goes deeper than that. To explain the lack of DXing activity we probably need to consider other factors. What are the motivations and rewards for working DX? For some it is simply the thrill of making that rare contact. For others it is the pursuit of long term achievements, collecting operating awards. There are many awards available to the 160 meter operator: DXCC, WAS, WAC, and many more. This isn’t true for the lower bands. For one thing, most awards are not even offered for these bands. If they were, most of the traditional major awards would not be attainable down here. DXCC is probably not possible for the vast majority of stations on 630 meters and probably not for anyone on 2200 meters. Propagation and the EIRP limits simply put it out of reach. WAS may be possible someday for those in North America (when we have active stations in all 50 states, which hasn’t happened yet) but is probably not possible for those in other parts of the world for the same reasons DXCC is impractical. WAC? Good luck, same problems. Are there in fact any available and reachable operating achievement awards for these bands? Not that I am aware of. So there is one motivation missing. If a well established and recognized organization offered attainable operating achievement awards for these bands, it might help to spur activity, perhaps even attracting more people to these bands in the first place.

Do these bands tend to attract a different group of people? Probably to some extent, yes. With lack of off affordable off the shelf equipment and no awards program, these bands may tend to attract mainly experimenters and those with special interests in low frequency radio. It may be that a large percentage are more interested in experimenting than in making QSOs. The results of the latest antenna change or transmitter upgrade can be easily and effectively assessed through beaconing, primarily using WSPR mode. One doesn’t need to be up late  sitting behind a radio for this. Clearly some of the operators who are on these bands are recognizable as DXers on higher bands — 160 meters, HF, even VHF and UHF. But they are a small minority.

I have given this a good deal of thought and continue to do so. What I have arrived at so far is a sense that we simply haven’t reached critical mass for DXing activity on either of these bands. It takes a certain amount of activity in in place to motivate most people to stay up late and get on the air. Even the most motivated operator may struggle to convince himself to be there night after night knowing there very likely is no one there to work. When activity is so low that there is very little chance of working anyone, the motivation is missing or insufficient. I am struggling with this myself. I am a very avid DXer  and I am very interested in trying to work as many stations and states as possible on 630 meters. But, looking at my unattended JT9 decodes each morning clearly shows the chances of working anyone out west on any given night are extremely low. So low, in fact, that I am usually unable to convince myself to stay up and try. Of course this works both ways as having few here in the east to look for probably keeps some in the west from being on every night. With the overall low number of capable stations, DX minded operators and fewer incentives driving the desire for QSOs, it is my opinion that we haven’t reached critical mass. There is not enough consistent activity to get the ball rolling and keep it rolling.

So how do we change this? Can it be changed? Would it help if there were a small group of extremely hard core DXers committed to CQing during key times every night? Perhaps this starts with those at the end of a DX path presenting more convenient hours. If those who would need to be up very late at night to make these QSOs had assurance that there were stations making noise, would this increase the likelihood that they would try? I am currently trying a limited run experiment along these lines, as I have committed to calling CQ every night this week for at least two hours during a time that is convenient for me and frequently offers propagation to Europe. The hours are not so convenient on the European end of the path! Unfortunately this experiment comes to an end when I finish repairs to the 2200 meter loading coil and return to that band. My one other thought on the subject is that those who do succeed in making DX QSOs on these bands should do everything possible to publicize this far and wide – both within and outside the LF/MF community. We need to show the world that long distance QSOs can be made on these bands! We need to promote them as QSO bands, as I believe the outside world still largely sees them as experimenter and beacon territory.

Update 10 January: Over the past several days an experiment was carried out. I announced that over a several night period I would be calling CQ on JT9 mode for at least two hours during the early part of the Europe to North America window (which tends to be the least inconvenient time for the Europeans). This attracted the attention of a few who indicated they would be looking for me. I promoted this as an activity period on both the European and North American email lists. I was joined on the North American side by NO3M and more casually by others. After a slow first night or two, I became the second in the U.S. to complete a trans-Atlantic QSO on 630 meters when I worked G3KEV (the first was AA1A working G0MRF several weeks earlier). Shortly thereafter, NO3M worked G3KEV. I had a partial QSO with PA0A. News of this success brought increasing interest. The following night both myself and NO3M worked G3KEV again. There were partial QSOs between N1BUG and OR7T, N1BUG and DK7FC, NO3M and DK7FC and possibly others but none of these were completed due to QSB or other factors. During this several night activity, hours of operation increased from two to four or more. That is a lot of chair time and CQing for very few QSOs. Clearly we have proven that many QSOs are possible but it will take dedication and effort. Frankly I do not have the stamina to sit there CQing four hours every night. If there were a large enough pool or interested operators to provide reasonable assurance that someone would be there every night, this might become self sustaining. As it is, we simply don’t have that level of activity.

Having more DX-minded operators on the bands would help. But getting on these bands can seem intimidating. There are some web sites that make it all sound so technical and complicated as to scare people away. It doesn’t have to be complicated. Probably the most challenging aspect is knowing what your EIRP is. If you can make basic measurements such as antenna system resistance and antenna current there are online calculators that take the work out of this. Chances are most hams have access to someone with the equipment to make such measurements if they don’t have it themselves.

Home built equipment can be very cost effective but one can buy a transmit converter for $80, a power meter for $40 and throw some wire in the air. If you don’t already have a receiver that works on these bands, there are inexpensive converters and simple SDRs that don’t cost an arm and a leg. There are some pricey equipment options out there. I don’t claim the cost is entirely unwarranted for those who can afford it. But it is not necessary to spend a fortune to get started or even to build a very capable close-to-high-end station. If you’re looking for intercontinental DX you will want to take the time to get up near the legal limit on EIRP but it can still be done on a budget.

For the time being, I suggest the most likely means of working DX is to organize and promote occasional “activity periods” where several stations at both ends of a DX path commit to calling CQ during a certain window for one or more nights. In the long term we need more DX-minded, motivated operators on the bands. Active promotion of the fun and challenge of DX QSOs on these bands is needed. A sensible awards program might be helpful.

A Low Drive 630 Meter Amplifier

My first attempt at amplifier building for the new low bands was a disaster. Being low on funds and patience at the time, I tried building a dual band “linear” amplifier that was said to be capable of 25 to 50 watts on both bands. It turned out to be a design plagued by problems which I won’t get into here. I was fretting about what to do next, as there was no budget at all, when Ken K5DNL came to the rescue. He kindly helped with parts and schematic for a modified, low drive version of the popular GW3UEP amplifier. Credit for the design goes to GW3UEP and K5DNL. Where I have made minor changes I will note that in this post.

Schematic of the low drive amplifier

Referring to the schematic, the 2N2222 provides additional gain to fulfill the low drive objective. This amplifier can be driven to full output with 0 dBm (one milliwatt) input. Mine actually produced full power down to -2 dBm but don’t count on every build being exactly the same. The BC550/BC560 pair forms a squarer to ensure we have a nice clean square wave to drive the FET. The FET in the original GW3UEP was a IRF540. Ken sent a couple of 30NF20 FETs which is what I used in mine. C2 and C4 were not on the schematic I received from Ken. After building it I found the gain and power output peak was around 505 kHz. Looking at the original design on GW3UEP’s web site I noted the the originally specified capacitor values were for that frequency, with a notation to add capacitors for 472-479 kHz operation. After I added C2 and C4, my amplifier peaked at 475 kHz. All capacitors in the FET output circuit should be good quality pulse rated film or silver mica. C1, C3, and C5 in my amplifier are WIMA FKP1. C2 and C4 are CM06 size silver mica with a 500 volt rating. The 1 uF DC blocking capacitor is a WIMA MKS4. Watch the capacitor voltage ratings. Theoretically, 100 volt capacitors should be good enough, though marginal if you intend to run on 24 volts. Some digging into spec sheets on the WIMA capacitors reveals voltage ratings are reduced as frequency increases and we are well down the slope on most of them at 475 kHz. If you are going to buy capacitors I suggest going with the highest voltage rating available. The other change I made was to relocate the blocking capacitor to the location shown. It was at the amplifier output on the schematic I received (and yes, if you are eagle-eyed you will see I have it at the output in the photo below. I relocated it later).

The completed amplifier. IMPORTANT NOTE: The 50 ohm shunt input resistor shown on the schematic is brown in color and mostly hidden under the input coax, just to the left of the 0.1 uF input coupling capacitor. The six blue resistors seen in the photo are not on the schematic. They form an input attenuator, needed because I am driving this amplifier with 250 milliwatts. The input attenuator takes that down to 1-2 milliwatts which is a perfect input level for the amplifier as shown in the schematic.

It should be noted that one need not use exactly the parallel combinations of capacitors specified. The important thing is that by whatever method, be it a single capacitor or several in parallel, we arrive at the required total capacitance at each point in the circuit. You will notice my capacitor combination at C3/C4 quite different from the original GW3UEP.

This amplifier should produce 30 watts output at 13 volts, 100 watts on 24 volts. I am running mine on 19 volts and getting about 65 watts out into a 50 ohm load. I have been running this amp on WSPR at 33% duty cycle for several days and it has performed perfectly. One should strive to keep the antenna resonant and matched, but mine has at times wandered off a bit with no ill affect on the amplifier aside from power output variation as the load impedance changes.

Note: This amplifier has a built in low pass filter but it does not meet FCC requirements for spectral purity. If you are subject to FCC regulations, you should use additional low pass filtering after this amplifier.

Building a 630-Meter Transmit Converter

Inside view of completed 630m transmit converter

This is a companion to my earlier 2200-meter transmit converter. Refer to that post for more details. This one produces about 25 dBm output. Not much is different here except for component values in the low pass filter and the trimmer potentiometer. I didn’t have another of the same type and value. It isn’t critical since it is only being used as a voltage divider to set bias on the BS170 FET.

 

 

 

 

Schematic diagram and parts values for the 630m transmit converter

Building a 2200-Meter Transmit Converter

I recently began running a WSPR beacon on 2200 meters. Beaconing is fine, but I also want to be able to make QSOs on this new band. To that end I needed a very low cost transmit converter so that I could use my FT-2000, which is fully interfaced to the computer for digital modes. Dave, AA1A came to the rescue with an old Anzac MD-143 mixer. The rest I built from stock parts and the junk box. Stock parts are new, current production parts I keep on hand for projects. The junkbox is a collection of old, surplus, used, salvaged and anything else I happen to be able to get my hands on. I don’t need a linear converter or amplifier for this band, and the resulting converter is not linear. It can be used on CW and any mode which does not require linear amplification.

The converter post-mixer amplification and low pass filter are separate from the mixer

The MD-143 takes a nominal 7 dBm local oscillator signal in the 5 to 500 MHz range. For RF it likes about 0 dBm in the same range. Conversion loss is around 6 dB so we can expect about -6 dBm output at the IF port, which is rated DC to 500 MHz. I wanted to get that up to 24 dBm (250 milliwatts) so it provide the same amplifier drive level as my Ultimate 3S beacon transmitter. The fewer things I have to remember when switching modes, bands, activities or exciters the better! I knew I could use a BS170 FET and low pass filter to duplicate the amplifier section of the Ultimate 3S but I would need something on the order of 10 dBm drive to assure equal output. Wayde, K3MF, suggested using a venerable 2N3904 and kindly sent a long a copy of a schematic. This was good because I have a drawer full of 2N3904 transistors! Some quick and dirty breadboarding and testing showed that I could get 12 dBm out of it with -6 dBm input from the mixer. Perfect!

Inside view of the completed post-mixer amplifier and low pass filter

I set about throwing a circuit together. I was only going to be building the post-mixer amplification and low pass filter stages since I wanted to use the Anzac mixer with this and a similar unit for 630 meters. It’s really very simple: a 2N3904 which produces a nice square wave output followed by a BS170 and finally a low pass filter. There is a 5 volt regulator to power the BS170 in order to hold it to the 24 dBm output level, same as in the Ultimate 3S which runs on 5 volts. After throwing the thing together, it showed exactly 24 dBm output on the first try! Whoa… let me note this on my calendar. It’s a historic occasion!

I am temporarily using my trusty HP 3325B function generator as a 10 MHz local oscillator. When I can afford it I plan to get a dedicated 10 MHz LO for this converter, ore more appropriately one that can be shared between this and its soon-to-be-built 630 meter counterpart. My FT-2000 has been modified for general coverage transmit so I can use it on both bands (10.135.7 to 10.137.8 for 2200 meters and 10.472 to 10.479 for 630 meters.

There is not much else to say about this. I am including a schematic for those who may wish to borrow ideas from this simple gadget. Unfortunately I am reduced to posting photographs of schematics since my printer/scanner finally died after many years of faithful service.

Schematic diagram of the post-mixer amp and LPF stages of the converter