Wednesday, May 31, 2023

Robots Invade 6 Meters

The return of 6 meters sporadic E marks my return to digital modes. With rare exceptions, my operating on digital modes is greater than 95% on 6 meters and the rest on 160 meters. I do the former for its superiority at exploiting rare and fleeting DX openings, and the latter when there is little CW activity to be found.

FT8 in particular is wildly popular. Since I have little interest in digital modes, I use the technology where it fits my interests and otherwise stick to CW and SSB. It's a matter of personal preference. I don't look down on those who predominantly operate digital modes. That's an attitude many hams of my generation regrettably profess.

Many of those attracted to digital do it to compensate for poor antennas. In the past that would drive them to CW, which is not an easy option for recent licensees that may not know CW. Others do it because the technology is fascinating. I would not be surprised to learn that some use digital to avoid unwanted conversations. All are valid reasons, in my opinion, even if mine are different.

It is no surprise that fully automatic -- or robot -- operation is seen on FT8. The software-driven technology is eminently suited to it and there are ample hams with the expertise to do it. After several years of there are numerous forks of the open source WSJT-X software that include automatic features.  All you need to do is download one of them and you, too, can be an FT8 robot.

Should you? Is it wrong? Automatic operation is certainly discouraged by the original software authors and operating award sponsors. Nevertheless it is popular and becoming more so. It is fairly easy to identify robots but difficult to prove with an acceptably small probability of false positives.

It is not my intent to write another critique of digital robots. There are enough of those, and I've spoken of it before. The phenomenon is of interest to me since as more and more hams migrate to 6 meters -- a passion of mine -- and the overwhelming popularity of digital modes, it impacts me every day during sporadic E season. It is worth pondering their prevalence rather than reflexively attacking robot operators.

As a 6 meter DXer, I have several issues with the presence of robots:

  • They occupy spectrum. Robots typically are configured to operate non-stop. The 3 kHz FT8 and FT4 windows can support a large number of signals, but there is a limit and we've reached it during many sporadic E openings. Not everyone will move to 50.323 MHz during hot DX openings.
  • They will call you, regardless of whether you call "CQ DX" or other target area. They will follow you around the band, often calling on your transmit frequency, thus QRMing many callers. They may continue this behaviour indefinitely, even after you stop transmitting.
  • Robots typically call anyone next in line according to algorithm and configuration, without respect to distance, grid or country. They fill their logs with what I consider fluff.

From my observations, it seems that those who run robots are not very good at configuring the software! A few simply may not care that they are an annoyance and causing QRM. However I don't believe that they're evil. I know a few of those who are almost certainly running robots on 6 meters and I would not consider them to be "bad" people. There are moral and ethical questions that have no clear answer. That I and many others dislike robots does not make them objectively "wrong".

Do you want to work them?

Apart from the issues addressed so far, is there anything objectionable about working a robot? For award and contest purposes, it is at least discouraged and will usually result in disqualification of the robot operator, if they're found out. Some are obvious but all are difficult to investigate. That can be a trial for award sponsors that prohibit robot QSOs. That is not my problem since I do nothing wrong by working robots.

I don't call stations that I know or strongly suspect is a robot. When they call me, I may work them despite my dislike. I sometimes do it just to be rid of them. Depending on my mood I may not log the QSO. In most cases I ignore them. There exist ports of the WSJT-X software that have black lists and related features for those that want to automatically ignore suspected robots.

If I'm in a mischievous mood I may toy with robot callers. I will change frequency, switch between odd and even periods, make one response (or one that is deliberately out of sequence) to see what they do. But only if I have a few minutes to waste. Probing their behaviour can help to better identify other robots. 

Let's try an extreme hypothetical situation. Imagine that the robot is in North Korea (P5). Is that enough to convince you to work it, whether it calls you or you answer its CQ? How about a robot dropped on the Moon by a future space mission or riding on the ISS or other satellite?

There is no right answer to these extreme cases. It is worth taking a few moments to consider what you would do. All could occur eventually.

Why do they do it?

No, I don't know why since I have spent little time trying to find out. In one case that I remember well, the ham shrugged his shoulders and said, "why not?" Maybe they don't know either. Does knowing why even matter? There could be as many reasons as there are robot operators.

As I said above, I don't think robot operators have evil intent. The technology makes it easy and it is admittedly interesting. I remember discussing the possibility of automatic CW operation with a friend of mine about 30 years ago. We decided it was possible but difficult, and eventually it would probably be done. Neither of us was interested in following through and it seems few others have bothered. 

With no QRM, QRN and QSB, and well formed characters, robotic CW operation can be done, though not without glitches. It isn't possible to anticipate every response to a transmission. Of course the CW robot could emulate a human operator who wants out of a conversation by forcing an end. A CW robot would have to be rude by design. Digital QSOs are far more structured and thus amenable to competent robotic operation.

One topic that I don't recall discussing with my friend was ethics; that is, the appropriateness of a CW robot. This is perhaps unsurprising. We were both software professionals with a love of CW, and beyond the technical challenge we ultimately thought the result would be quite boring. Why hand over operating to a robot? We want to be the operators! That's why we became hams.

With that limited insight, I doubt that most FT8 robot operators are overly concerned about its ethics. They stay quiet about their activities since they know others would question their ethics. 

Robot operation may be interesting, but a brief passion that is soon discarded. Operating is more fun to do than watch. But if for whatever reason you want to fill the log with contacts and your life keeps you out of the shack, or you want the contacts without the "tedium" of operating, a robot might be tempting.

Where next?

One curiosity about the robots I've identified is that they have clean signals. I can't say the same for not a few of the 6 meter stalwarts! That's likely because they don't use amplifiers and run their rigs conservatively. The duty cycle of FT8 is hard on transmitters and amplifiers that are run non-stop close to the equipment power capability. Robot operation may be annoying and unethical but robot operators aren't stupid.

That is good since robots aren't going anywhere. I expect their number to grow, though slowly and it will likely plateau. While many may at first be enticed by the technology and QSO potential, it is ultimately boring. Individual robot operators will gradually scale back or give it up entirely. Peer pressure from local hams can also be effective. Shaking your fist at the computer display is not effective.

I'll close by noting that I have not mentioned any robot FT8 applications. They're out there and easy to find. I have no reason to make the search easy.

Thursday, May 25, 2023

New Capacitance Hats for the 40 Meter Yagi

The design of the capacitance hats for the 3-element 40 meter yagi has proven to be inadequate. I misjudged the various mechanical stresses and the effects of wind and ice. The antenna is very big, with a huge wind load, and it is greatly exposed to the weather at its height of 43 meters above ground.

Two capacitance hat arms broke off since it was raised. That's out of 24 arms: 3 elements × 2 hats per element × 4 arms per hat. Modelling shows that the performance impact is not all that bad, and on the air it continues to perform very well. But I can't afford further breakage. 

The time has come to deal with the flaw. I don't hide my mistakes on this blog. This is about learning, both for me and for you. There is no shame in admitting mistakes and letting others see how I deal with them. Hence this article where I describe the flaw and my revised design.

I was aware of the flaw when I designed and built the capacitance hats. I judged (but did not calculate) that the joint to the element would be sufficiently robust. When I raised the experimental dipole and left it on the tower for close to a year, one objective was to see whether the clamps would survive. They did so I kept the design. There are so many challenges with an antenna this size that every work item that I could eliminate left more time to deal with others.

Let's look at those stress points. The centre tube of the capacitance hat arms are ½" × 0.065". The u-bolt is ¼". The pair of bolt holes per u-bolt arm are half the tube diameter, or about ⅓ the circumference. That's a lot to ask from 6061-T6 alloy. 

I had intended that the thick mating clamp made from a ¾" × ⅛" tube mitigate the stress where it crosses the 1" element tube, while also preventing slippage. It seemed an elegant solution at the time.

After surviving for one year at 46 meters height in the experimental dipole I decided it would do. I was simply lucky in hindsight. There is stress from the nut which squeezes the tube. There is also stress from wind and ice load on the arms, which range in length from 42" to 48". The fatigue was worse than I anticipated.  Both broken arms failed at the outer edge of the bolt holes.

Originally I planned for the ¾" tube to remain whole and enclose the ½" tube. A 3" length would have been enough. I cut the tube longitudinally to save weight when I decided that was the greater concern.  The "dimple" where it crosses the element could have been kept with the whole tube.

I considered several alternatives to replace the capacitance hats. I kept the same arm tubes but with a different design at the centre where stress is highest. The same u-bolts secure a 3" length of ¾" × ⅛" 6061-T6 angle stock. The ½" tube passes inside a length of ⅝" × 0.058" tube. The tubes are secured to the angle stock with #8 stainless screws. The ⅝" tube is slit at both ends and compressed with a #8 stainless screw. The slit and screw are needed for a good electrical bond at the joint, and not so much for mechanical strength.

The length of the ⅝" tube is 8". These first arms of the new design are for the driven element. They may be shorter or longer for the director and reflector elements when I build them. Although the capacitance hat arms on the driven element are okay, they are easily accessed from the tower by rotating the element on the boom. I can thus test the new design without undue effort.

Installing the new hats wasn't very difficult, apart from the climbing. I turned the yagi so that the driven element could be rotated in both directions to near vertical without hitting a guy or other obstruction. It is high enough above the lower 10 meter yagi of the stack to not hit it, and the upper side of the element passes between the elements of the upper 10 meter yagi.

One of the 4 capacitance hat arms being removed from the driven element shows clear evidence of fatigue. Within days or weeks this arm would have broken off. The other three were fine, so far. Eventually they would likely fail.

The plated u-bolts are beginning to rust after 18 months. It isn't a surprise. Galvanized or stainless bolts are used everywhere else on the antenna but were not easily available in the 1" size when I was building the antenna. The rust does not affect antenna performance since there is aluminum to aluminum contact via the clamp. I'll look for better bolts before all the other capacitance hat arms are repaired.

To avoid accidents, I first replaced the inside arms. The outside arms, which are at the bottom when the element is rotated on the boom, prevent it sliding off. Despite my care I managed to drop one of the new capacitance hat arms. 

It is tricky to bundle them for climbing and safely extract them one at a time. Due to interference of the element with the boom truss and the capacitance hats with the tower, I had to reach outward about 2' to do the work while holding all the pieces of the assembly. The dropped arm survived the fall from 130' (20' below the top of the tower) despite bouncing off a guy. The arms are long but light so they (happily) have a slow terminal velocity!

The new arms look good on the driven element. It isn't critical to get the two arms snug to each other since on 40 meters an inch makes very little difference. They are wider than the original arms due to the angle stock alongside the tube and I had to keep them clear of the screws and nuts securing the 1" and ⅝" element sections.

Now I wait to see learn how they perform over the coming months. If they do well I'll proceed to replace the capacitance hats on the other elements. Apart from the ⅜" tubes, the rest of the original arms will be discarded.

So near and yet so far

Accessing the capacitance hats on the driven element is easy. The same is not true for those on the director and reflector.

This is one of those nasty challenges you will inevitably run into with big towers and antennas. Replacing the capacitance hats on the director and reflector will not be easy. I have done some planning with a friend on a method of doing the replacement that does not involve taking the antenna down or a large crane. It won't happen sooner than late summer so we have time to get it right.

It is better to build it right the first time so that you never run into this predicament. I do pretty well but I'm far from perfect. To err is human.

Monday, May 15, 2023

Hello, Goodbye - In Praise of 599 QSOs

I was not too different from many other boys (and a few girls) when I started in ham radio over 50 years ago. I was more comfortable with machines than with people. I was shy and nerdy, and I took to electronics, radio and computers like a fish to water. Amateur radio was a perfect outlet for my enthusiasms. 

The downside was that the practice of amateur radio, the fruit of learning the code and building a station, was talking to people. Certainly I was thrilled with the possibility of contacting people all over the world, especially in the 1970s before the public internet, affordable long distance telephone service and commercial wireless services, but shyness and feeling intimidated by adults caused anxiety. 

One of my fears was that my QSO partner would take the conversation beyond signal report, name, QTH, weather and station info. I never really knew what to say. As far as I was concerned, the shorter the QSO the better. I felt that anxiety every time I reached for the key or microphone to respond to a CQ.

The attitude of the adult hams in my life may have been part of the problem. They were less encouraging than you might think. Many were pleasant but quite a few seemed to find youth annoying -- we were inquisitive, ignorant and unruly. This was a time when the prevailing wisdom was that children were meant to be seen and not heard. They were good people but the generation gap was difficult to bridge. 

Instead of adult ham mentors, I learned from other young hams, magazines and from my on air experience. We were the middle wave of the baby boom and there was no shortage of other hams my age. We paid little attention to adult hams and many of them did the same. I was never comfortable talking to them on the air.

My friends and I soon discovered contesting. Young adults are always trying to "test ourselves" and make a mark in the world -- having our calls printed in a magazine. I could make oodles of contacts with anyone and everyone in a few hours with my small station and without the anxiety of having conversations. It was perfect for me. I formed close friendships with peers who were also drawn to contests. We spurred each other to improve our stations so that we could do better against the "big boys".

Conversations: is that the point?

Many hams who do not like contests or DXing cite as their reason the absence of conversation. The exchange of little more than a signal report in endless succession is pointless to them and a waste of time and spectrum. They are not wrong, for themselves and their interests. Obviously many of us feel differently. 

As teenagers we would mock adult hams for their lengthy and boring rag chews, nets that did nothing but take check-ins and, for the oldest, endless blather about their health woes. Few young people have the patience for any of that. When we did talk to each other on air we talked like the teenagers we were, and that irritated many of the adults who listened.

The objective of a contest QSO is to correctly exchange information with others as quickly as possible. There is little time to spare for anything more. When you run into a friend on CW you might just send "dit dit" to acknowledge them. Time is of the essence and all participants understand that and so both hams race to make the next contact. The same is true for DXpeditions that aim to hand out the maximum number of contacts as possible.

This does not mean that contesters don't talk to each other. I suspect that contesters talk to each other more than most non-contesters. But they do it outside of contests. Sometimes on air though more often in person, on the phone, in online fora and at hamfests. We share stories, talk about what did and didn't work, help each other to improve our stations and skills, and gather as multi-op teams and spend the weekend enjoying each other's company.

Hams who value conversation above other styles of operating may decry the spectrum occupied by contests and DXpeditions. This was a greater problem decades ago when the bands were packed on weekends by hams filled the bands with conventional QSOs and contesters were in the minority. 

These days the spectrum is emptier when there is no contest. Conversations are less popular and contests are more popular. This is likely to continue. Modern technology makes talking to other people, near and far, easier and cheaper than ever for hams and non-hams alike, so that is less of a draw to the hobby than it once was.

Contests and DX: speed and agility are everything

In radiosport, time is of the essence. I don't dawdle and I don't like it when others dawdle. I'll slow down when I must to complete the contact. When I'm running and several stations call, I am likely to choose the fastest.

Think of it as choosing a lineup for the cashiers in a store. Do you choose the one where the cashier or customer is chatty and striking up a conversation or the one where neither says a word and they stick to business. I choose the latter. Conversation is nice but even as a retired person I'd rather take the faster line up so that I can move more quickly. That isn't unfriendly or rude. I appreciate fast service.

Despite that, a conversational QSO is vital CW practice, and I make a point of doing it from time to time. I love Morse but I have no talent for it. It was a struggle to learn to copy and send when I started out long ago and that's still true. In a conversation you can't readily predict what the other ham will send and that makes me concentrate and not lose any vital characters or information. That skill makes a difference in contests even though the exchange is more predictable.


Digital QSOs aren't very fast, but they stick to the essentials: call sign and signal report. It isn't possible to have a conversation with digital modes like FT8. Well, it is possible but so difficult that few bother to compose messages on the fly.

I don't mind the simplicity of digital contacts, though many do. Those who decry the hello-goodbye QSOs typical of contests and DXing are, not unexpectedly, skeptical or hostile to digital modes. The absence of conversational possibilities can be an advantage since no one can keep me into a QSO longer than I'd like.

Are hams that preferentially operate digital modes loners and losers? No! Like contesters they do their talking when meeting with friends and local club members, on air and off air. They are happy, well adjusted human beings that happen to enjoy and appreciate the benefits of digital modes.

The future

I am no longer a shy teenager. I'm comfortable speaking in front of an audience of 1000 people and conversing on air. Yet I continue to prefer "599" QSOs. During our long and cold winters I will occasionally get on the air to talk. It doesn't happen often.

When I take the time to chat on SSB with my large station, not a few are surprised to have never spoken to me before. A big signal from an unrecognized station is a curiosity to those who regularly scan the bands looking for conversations.

Conversational QSOs are a secondary interest for me, but when a QSO partner wants more I am usually happy to oblige. More often I'd rather have a brief contact and move on. Perhaps I'll learn to enjoy the simple pleasure of having on air conversations when I'm older and I've put aside antenna and tower projects.

Friday, May 5, 2023

50313: Share What You Hear

It's May and sporadic E season has arrived. Single hop and DX openings on 6 meters are becoming more frequent. I have resumed daily monitoring 6 meters. It is my habit to monitor 50.313 MHz with the yagi pointing in a likely (or hopeful) direction when I am elsewhere or not using the station on HF. Computer cycles are free and, who knows, surprises happen.

Apart from my own benefit from this practice, I am also helping others. There are many 6 meter enthusiasts around the world that periodically CQ when conditions are promising, and even when not, to see what they can turn up. Most often nothing is heard. But there's more to it than that.

Revisiting discovery

One of the great benefits of digital modes like FT8 is the ease of discovery. There is no need to constantly spin the VFO knob to hunt for stations. Although I am a strong believer in knob turning, it is not so practical for elusive sporadic E openings. 

The band opens for 2 minutes, a DX station or two pops out of the noise...but you miss the chance of a QSO because your VFO is elsewhere. Or you've grown weary of spinning the knob and you're taking a break. There goes your chance for a new DXCC country. Automatic scanning helps somewhat but it is still far from reliable. Think about how easy it is to miss a CW station as you tune past. All it takes is swishing past during the space between characters and you hear nothing.

You can tune to one of the many beacons on 6 meters and just sit there waiting for a signal. They're still there despite the prevalent use of digital modes, they're just not as necessary as they once were. When you hear a signal in Europe, what should you do? You can't work the beacon so back you go to spinning the knob or calling endless CQs, often to no avail. Sporadic E is really sporadic! Hearing a beacon is not always indicative of a broader opening or the presence of stations to work.

By monitoring the community FT8 watering hole at 50.313 MHz you will decode all signals that propagation brings your way. You can quickly see the activity and respond. The probability of a successful QSO under marginal conditions is far greater than on CW or SSB. When conditions are hot, move to the intercontinental DX window at 50.323 MHz to escape the QRM.

Where I'm being heard

We can do better. Here is a map produced by PSK Reporter from a recent opening. It shows where and when I was heard on 50.313 MHz FT8. The data comes from stations that upload their decoded messages to PSK Reporter.

I am highlighting OA4DYQ since I had just worked him for a new digital DXCC entity on 6 meters. The QSO was barely possible as you can see by his reception report of -21 db. His signal was about the same relative strength here. Notice in how many countries my signal was decoded.

Scratch my back and...

...I'll scratch yours. Returning a favour is not only polite. Everyone active on 6 meters benefits. Click one box and you're done. Unlike DX spotting networks, the spots do not have to be done manually for others to learn what you are hearing.

Check the box labelled "Enable PSK Reporter Spotting" and you're done (JTDX also has this feature). As you monitor, call signs and signal reports are uploaded to PSK Reporter in near real time. Since OA4DYQ was doing that, I could browse to the PSK Reporter mapping page, enter my call and select the band and mode to see that he is receiving me. 

I am surprised that many stations are not yet connected to PSK Reporter. When I work them I notice that they are not on the map. Perhaps this is a carryover from HF where there are so many active stations that there is less incentive to enable the feature. For the fickle propagation found on 6 meters it is very helpful for more stations to use the PSK Reporter service so that we can see what other stations are hearing. Knowing that the band is open spurs me to keep sending CQ. Those map markers tell you who is monitoring and I want to light them up.

Of course there are many stations in remote areas without a reliable internet connection. The rest of us should not overlook this valuable feature, which is why I am motivated to talk about it again at the start of a new sporadic E season.

I mentioned in a article two years ago how these reports led me to a wholly unexpected opening to Japan. On seeing a flag in Japan, I turned the yagi and immediately worked JA8EPO. That's the power of PSK Reporter. Those flags may be the only indication that a DX path is open.

Many 6 meter stalwarts make a point of testing propagation with a string of CQs and see what shows up on PSK Reporter. I am often surprised where I'm being heard.

Single Decodes

Marginal signals that have only one isolated decoded message are not workable, so why care? I care because it shows the potential of a workable opening. When I see them, I know to keep watching the propagation path for further developments or call CQ. Often nothing further develops. Other times it is the harbinger of a superb DX opening.

The single decode may be due to a short-lived zone of intense ionization in just the right spot in the E layer. It could also be a random meteor trail that foretells nothing of great interest. However, a meteor in the right place at the right time can combine with sporadic E or F layer propagation to result in a short-lived propagation path. Other combinations also may form, such as the more common sporadic E and TEP to bring South American signals to this part of North America.

Each isolated decode is enticing since there is no certain way to tell if a workable path will open. Keep monitoring or try to light up those PSK Reporter flags with a CQ. 

When you upload to PSK Reporter you are encouraging the DX stations to keep trying. You want that, to let them know that you hear them, even though they may be unworkable or you are not in the shack. They'll know propagation is present to your part of the world.

The coming maximum

With the peak of the solar cycle rapidly approaching, the opportunities for propagation modes that connect sporadic E to F-layer modes will increase. F-layer propagation on its own is fantastic but we don't yet know how high the maximum will go this solar cycle. 

The better the maximum, the better the traditional CW and SSB modes will work. Not everyone likes digital. There will be something for everyone. If the solar maximum turns out to be a dud, expect digital to continue to account for at least 90% of 6 meter DX contacts. Use the mode that suits the propagation to maximize DX success. The ionosphere is not obligated to do what we like, so be flexible.

That's enough for this article. Looking through my posting history there are an awful lot of articles about 6 meters and 6 meter DXing. It's one of my passions. Since the web statistics show that those articles are quite popular, many of you must feel the same way.