Saturday, July 5, 2025

Designing a Better Antenna Selector

When you purchase a product you accept the decisions of its designer. If those choices are unacceptable you can turn to a competitor's product. Griping about what you don't like accomplishes little. Sell it and move on. We all make mistakes.

When you choose to design and build your own equipment and you don't like it, you can only blame yourself. Discard it and purchase a commercial product. Or you can try again. For my custom software-based antenna selector, I am trying again.

Design iterations are at a far slower pace than I'd like. That's the penalty of doing it myself. Were I to apply myself full time to the effort it would have been accomplished long ago. But this is not a job and my time is filled by other projects and non-radio activities. So it happens when it happens.

I will point you at the article in which I initially described the system for details that I won't repeat here. I have also written about many of its shortcomings that became especially apparent during a multi-op contest. If a guest operator can't figure it out with a modest amount of acclimatization, there is something amiss. A good and intuitive UI (user interface) and UX (user experience) is difficult to achieve. Many ham radio software products don't even try.

A major source of the existing system UI issues were due to my original hardware-based design. Its complexity reflected the complexity of my station, and the necessity of switches and LEDs to communicate system state and buttons and switches for antenna selections. I cast it aside and did what I should have done at the outset, which was a software-based system. My mistake was to keep too many of the original features that were driven by my self-imposed hardware mindset.

The UI on the PC screen is just one component of the antenna selector system. It is in communication with an Arduino that houses the actual antenna switching software. A final component is the assembly of relays and electronic switches which control the multitude of switches scattered in the field and on the towers. But all of that is hidden from the operator; the UI is the visible face of the system.

My intent is to replace the UI while leaving the rest of the system as is. I have been deferring new features in anticipation of the UI redesign. New features can be added later.

While many of the deficiencies were mentioned in the previously linked articles, here is a quick rundown. The screenshot shows a slightly modified UI to accommodate the reversing function of the new 40 meter reversible Moxon

  • There is no list of available antennas on the selected band. The antenna selector buttons (top row, second from both the left and right) select the next available antenna for the band in a predetermined order. An antenna that in use by the other radio is skipped. Essential data is hidden repeated clicking is slow and prone to errors.
  • Several antennas can alternatively be selected with the High/Low buttons for the low bands (160, 80, 40). That's confusing to guest operators, and occasionally myself. My intent was to achieve functionality similar to that of the stack selectors for the high bands. It was an idea that sounded good in theory but not in practice!
  • It is easy to click the wrong mode and direction buttons. For example, selecting "20 Hi" instead of "15 Hi" because you fail to notice which radio and band you're on. The mistake is particularly easy to make when dealing with the intensity of SO2R and 2BSIQ.
  • The direction buttons are not sensibly arranged. This was a temporary solution until I had time to expand the UI to include a bearing map centred on my location. Temporary solutions tend towards permanence.
  • There are two Beverage receive systems. The UI only controls the large 6-direction system and not the new 2-direction system (eventually 3). The switch box for them supports swapping the systems between radios, while the software does not. Hardware and software must change.
  • Lack of manual override and reset features when communication with the logging software or Arduino is lost due to RFI or bugs. It doesn't often happen but when it does it disrupts contest operation for a few minutes.
  • Knowing where an antenna is pointed. Guest operators have difficulty remembering all of the antennas, and associating a physical rotator controller with an antenna (or antennas).
  • Separate UIs on different computers for multi-op contests are needed. Although the new UI won't support that immediately the UI should accommodate SO1R, SO2R and multi-op with a unitary design. Having one UI on a PC between the operators, and sharing the mouse, is far from ideal.

That's a frighteningly long list! I can only do the work in stages, so I will aim to do the high impact items first. Before I can do that I need to develop a new UI framework that addresses the major defects. After that it's features that go "under the hood" and are therefore less impactful to the UX.

To familiarize myself with alternative layouts I took to Python to construct a "dummy" UI that I could play with. Alterations are easy since the experimental UI is a facade with no code behind it. As for the existing UI I turned to Tk since that's what I'm most familiar with. Others prefer a web interface or other UI packages. There are many to choose from and I won't recommend one over another.

The following is my first draft for the new UI. Embellishment has been omitted, such as the use of colour cues which are used in the current design. A simple construct is sufficient to prototype the design process without getting bogged down in details. It is more useful than a paper exercise since it is tangible.

Although it appears bulkier, the area of the window is almost identical to the original. This is critical to conserving screen real estate. I like to fit all critical windows needed for contests onto one PC display.

These are the principal attributes of the new UI, and how they are intended to address the listed shortcomings of the current UI.

  • All of the possible antennas for a band are shown. The fixed layout limits this to 6. That seems plenty except that the number includes stack configurations and direction switching. For example, all 6 are used on 80 meters.
  • Unavailable antennas will have their buttons disabled and given a distinct colour (not shown) so that the operator knows at a glance which antenna is in use and what is and isn't available. 
  • Showing the antennas for the other radio can aid communication between operators (even if it's one SO2R op) to request an antenna that is in use. I do not use triplexers or similar equipment to allow simultaneous sharing.
  • Multi-op use will display the other side of the UI for situational awareness. Left and right radios will be distinct by their position and colours, and that is the case whether multi-op or SO2R. Note that I removed the R1 and R2 labels since they are largely superfluous.
  • Fixed antenna directions are also shown in the adjacent direction box. Omni-directional antennas are shown with an "O" which (to me) conveys the meaning. I tried leaving it blank but that proved to be confusing and required spending more time interpretting the displayed information. The direction boxes may in time allow direction selection for rotatable antennas.
  • The receive antenna directions are shown on a great circle map centred on my QTH. Depending on the system employed, buttons will be enabled or disabled. It is fortunate in my case that the direction buttons don't cover any significant land mass. The direction labels may be redundant since their positions on the map seem sufficient.
  • The bottom row of buttons are to enable/disable receive antennas and to select the Beverage system. I may add the capability to cause receive antenna selection to command the rig to enable/disable the receive antenna port. I do it now with a soft button on N1MM's bandmap window but that requires an extra mouse click. The button layout requires more thought.
  • The top row shows no buttons to control the Arduino. I would like at least a reset button for rapid recovery from most bugs and RFI glitches. Additional buttons may be added to toggle BPF insertion and automatic/manual operation, and to restrict operation to contest bands versus all bands. Note that I use the antenna selector for all HF operating, not just for contests.
  • Extendible to new antennas and features as the station continues to evolve. There won't be too many new antennas but change is integral to my amateur radio journey.

It is not the purpose of the UI to please everyone. Others would surely make different choices. Some I might like if they don't over-complicate implementation. There are also many hams, especially older ones, that will always prefer the tactile feel of knobs and switches. I've moved past that. The only physical feedback is the click clack of relays under the operating desk. Even that will disappear should I move the switching components out of the shack -- there is no reason to keep them near other than ease of maintenance or for disconnection when lightning approaches.

Ideally the UI will in a sense disappear. It can be counter-intuitive that a well designed product doesn't draw attention to itself because it works so well. I doubt that I'll achieve this lofty ideal. I will be satisfied when it enables operators -- myself and guests unfamiliar with the station -- to do what they need to do with minimal friction.

There is more design work ahead of me. I would like to begin implementation this summer and finish it by year end. The work won't take 6 months of effort, it's just that this is one of many things that I need to get done.

Sunday, June 29, 2025

6 Meters: Mid-season Update

The first half of the 6 meter sporadic E season has been below par. At least in this part of the world, but not everywhere. I mentioned at the start of the season that there is some evidence that sporadic E is less frequent during solar maxima. While that may indeed be true it hardly seems relevant when the solar flux is so low (~120 as I type this). Even the aurorae during frequent geomagnetic disturbances have netted few contacts.

Yes, I'm griping. My friends are tired of my griping so I decided to continue on the blog with its larger audience. Lucky you (but you don't have to continue reading).

There is sporadic E nearly every day. The problem is that DX is largely absent. What propagation there is tends to only bring in the DX big guns, and they're very weak. Although that's welcome, other than an opportunity to say "hi" it isn't productive. I want (or need) stronger and farther DX, especially new countries. 

My expectations are difficult to achieve compared to most others since I have 147 DXCC countries worked and 135 confirmed. The only new country I've worked in 2025 (#147) was 4U1UN. The path from FN24 to FN30 is short but difficult. A large part of the difficulty is that they don't hear well -- it's a noisy location. It can be quite frustrating to hear them often while knowing that I cannot be heard.

The path can be bridged with rare intense sporadic E or tropospheric enhancement, and it has to happen when they're on the air. Friends have been more fortunate by being on at the right time. Finally it was my turn.

There has been just one widescale opening to Europe. It happened earlier this month. That was fun but, again, no new countries. There are very few countries in Europe that I still need. Examples include Z6, OY, T7, JX, JW). Some have been active this year and more operations are planned. Since most do not have big 6 meter signals or are far north they are difficult to work from here.

What we have had is a lot of trans-NA propagation. The FFMA chasers in eastern NA have been thrilled to work many needed DM, CN, and DN grid squares. The screenshot is from one of those openings. Although I don't chase grids I will work them since they're almost DX and I like to beam west in case the propagation extends into the Pacific Ocean. 

While working the opening I frequently check PSK Reporter for flags in Hawaii, New Zealand and the small number of 6 meter stations active in the vast area of the southern Pacific Ocean. It is unusual that we'd get a Pacific opening without a west coast opening, so we have to hunt for them amid the QRM. The exception is F2 openings. Since the solar flux this year is not cooperating we must rely on sporadic E links to long DX paths. Strong W6/7 and XE signals get me to pay close attention.

It would be nice if more stations would QSY to 50.323 MHZ for inter-continental DX chasing to escape the QRM on 313. This picture of the Icom 7610 spectrogram was taken during the same opening as above. There are a few DX chasers on 323 with strong signals but little else. It is perhaps a lot to ask of stations to move away from 50.313 MHz since that's a great place to monitor for openings. Everybody hangs out there. The quieter 323 makes it easier to spot the rare DX station but only if they're there.

There is no good solution. All I can do is QSY back and forth. That's no different from spinning the VFO on CW and SSB to find stations to work. No one promised that this would be easy! The DX hunt is difficult and that's integral to the challenge. 

Another point is that although FT4 is ideal for strong openings it continues to attract little activity. When I go to 50.318 MHz I can quickly work a handful of stations and then there's nothing more. Although FT4 can be more stressful since it requires quicker reflexes than FT8, you can select the auto-answer option. 

I prefer to pick and choose, especially when I call CQ DX and attract callers that don't respect my request for DX. I may enable auto-answer when I attract a pile up so that I always respond to someone without delay. I can override the software's choice if I do it quickly.

We had propagation to central Asia (UN) last week. As is typical with these long paths, it was unstable. I tried to work a couple of UN stations that were not in my log but could not. I didn't call the stations I'd already worked because so many North Americans were calling them. During the same openings I heard a few stations calling EX and EK. I don't know if they were successful.

I haven't yet heard Japan this season although they have been worked by stations to the south and west of us. There are reports of JA being heard only a few hundred kilometers away so I remain hopeful for one or more July openings. With luck an opening will extend to the mainland (HL and BY) or south to DU.

Speaking of south, DX propagation is more frequent at lower latitudes. We can only watch when W4, W3 and even W2 stations have openings to Europe, Japan and Africa. A little luck is necessary at our higher geomagnetic latitude. While seemingly not south of us, Europe has had numerous openings to Asia and Australia. Their more southerly geomagnetic latitude is responsible. 

Openings to South America are more common for us due to TEP, as it is in Europe (to Africa) and east Asia (to VK/ZL). Since I've worked most of the South American countries I often sit out these openings. They are mostly of interest to grid hunters. I listen to but rarely call stations in countries I've already confirmed.

Turning to the southeast, very little in southern Africa has been heard. On one day I heard 9J2FI briefly but couldn't get his attention. He's been heard more frequently in W1/2 and VE1. D2UY has been heard more frequently but that path is more to the east rather than southeast. There has been no sign of 7Q stations this season. I don't know if that's due to propagation or inactivity. I don't recall seeing any spots for them.

No Pacific stations have been heard this season. Stations as close as W8 and more westerly VE3 were able to hear and perhaps work KH6, 3D, FK, ZL and a few others. ZL1RS's recent DXpedition to E6 was invisible, unlike E51EME last year. Last year we had the benefit of a high solar flux. Now we must rely on more elusive long haul sporadic E, just like during a solar minimum.

Recently my power level has taken a dive. My Acom 1500 amplifier developed a fault and it won't run for long before the protection circuits kick in. It appears to be a problem in the protection circuits rather than the 4CX1000 tube. If I can't fix it myself I'll have to send it out of country to an Acom service outlet. Amplifiers are not very complicated but they are dangerous to work on due to the lethal voltages. In the picture you can see that I've overridden the safety switches to troubleshoot the fault.

For the time being I'm using the Acom 1200S. It isn't capable of as much power on digital modes so it incurs a penalty of about -1.5 db. Considering the variability of sporadic E propagation that isn't a large sacrifice. It is unlikely that the 1500 will be back in service before August.

Where do we go from here? From all indications, there will not be a second peak in this solar cycle, or not one of significant intensity. If I'm wrong and the solar flux rises in the fall we will have opportunities for long haul DX. That would be cycle 25's final hurrah. In 2026 we can expect few if any F-layer openings at this latitude. Beyond that, nothing until the next maximum ~10 years hence. 

I'll count myself very fortunate to reach 150 countries (worked) by the end of 2025. If propagation fails to improve I can at least look forward to DXpeditions to a few Caribbean and South American countries I have yet to work.

All I can do for now is wait and watch. It is often the case that when the first half of the season (up to the June 21 solstice) is poor the second half shines. Well, that's what I keep telling myself!

Sunday, June 22, 2025

Aging Tower Riggers

You realize there's trouble on the tower. Who are you going to call? If you're like the large majority of hams, you need someone else to do the work because you won't or you can't.

That is the question for most hams with towers since they don't climb. So you call a friend who climbs, ask your local club for assistance or you turn to a professional.

I don't have statistics to back me up but I don't believe it was always this way. When I was young, and for a long time after, I was one among many. It was common to ask a younger ham to help with their tower and antenna needs. I've been doing tower work for other hams as long as I've been doing tower work, and that is half a century!

It shouldn't be surprising. As we age we are less willing or less able to climb. It took me some time to notice the trend and where it is headed. Hams that still climb into their 80s are rare. Even the most ardent stop in their 70s. Many give up far younger. 

It is important to recognize when the time has come and willingly hang up the harness. Others are pressured by family. There are a stubborn few that keep going and pay a heavy price. I know hams that have taken down their towers when they realized they could no longer maintain them on their own. Help may be hard to find and some are too proud to ask. So they avoid the problem entirely.

It is older hams that are most interested in big HF antenna systems and most of the climbers in this cohort have aged out doing tower work. Few young hams are taking their places. Why would they bother to learn and practice those skills when they don't have a tower themselves. Many young hams are more attracted to portable operation or low profile wire antennas.

That's the situation: our number are declining so the downward trend will continue. I can count on one hand the number of local hams I personally know who climb. Many are eager to help, but on the ground. Indeed there is only one local ham willing and able to climb my tallest 150' tower. But then he has towers of his own that high.

Since it is getting harder to find hams to help on the tower, many turn to professional help. That can be expensive. Well, many things are expensive these days, whether it's a vehicle repair, redoing a roof or many other specialized jobs that require skill and experience. Everybody needs to eat -- so you pay.

How much can you afford to pay for the rest of your ham career? Can you find competent help? That is more difficult than you might think. Incompetent help is, unfortunately, far from rare. Not all that advertise their services deserve to be called professionals. It may mean little more than someone who charges for a job, whether or not it is done properly.

You can't inspect what was done from the ground so poor workmanship may remain undiscovered until well after money changes hands. I've often had to fix what I could when shoddy work causes trouble. I don't enjoy seeing fellow hams ripped off.

Few tower riggers are hams so that even if they are competent they may be unfamiliar with our equipment and practices. For example, weatherproofing connectors for ease of future disassembly, rotation loops and rotators, adjustment of feed point matching networks, the fragility of many aluminum and wire element yagis, etc.

There are alternatives. If the tower isn't too high you can rent a bucket truck and do the work yourself. It isn't as easy or safe as you might expect but at least you don't have to climb. Or you can install a crank-up or tilt-over tower. None of these come cheap. If it's important to keep your HF capability, you have the money and can't rely on hiring competent tower workers, by all means go ahead and do what you must.

I won't climb forever. At the moment I am in good physical condition and I have the requisite skill and experience. Since I'm retired I have time to help others, so I do that despite having my own large station to maintain and grow. I enjoy helping others. That said, my "best before date" has passed. My time is coming. Not soon, I hope, but it is coming.

Let's say that time is 10 years away -- 2035. What then? Will there be a younger ham, perhaps with operating opportunities, to do an old man a favour? Do I hire professionals? Many of the ones I know are also getting older.

I expect that I'll be able to afford the expense for a time. To minimize the need my plan is to cease antenna projects when the time approaches and harden the station as well as I can. The inertia of a solid tower and antenna installation may take me over the finish line. 

I have enough antennas that the loss of one or two is survivable. When I say loss, that could be an item as minor as an intermittent coax connector or a corroded wire on a rotator. But if I can't fix it, it's no less a loss of capability than if the antenna were to fall to the ground.

Sad to say that when I'm gone the towers will likely be cut down for scrap. I doubt that I can pass the station on, and it is too expensive to dismantle for sale in the unlikely case that there is interest in the towers and antennas. 

Ham radio will survive me but it will be nothing like what those my age grew up with. Tower work will become a skill lost to hams, just like what will eventually happen with CW and other traditional practices. Time marches on.

Tuesday, June 17, 2025

New Prop Pitch Motor Controller

This project has occasionally appeared in this blog, and has been so for a long time. There were complications and distractions along the way that kept me from getting it done. I am happy to report that it is complete, working and installed in the station. There's a welcome check mark on my lengthy to-do list.

Before going further I'll mention that there are many features present in commercial controllers that I have not implemented. I'll get to some of those eventually. Since they're mostly software, upgrades can be made with the controller in service. What I judge to be the important functionality gaps will be listed at the end of this article.

My requirements for the controller are simple enough:

  • No larger than a commercial controller, suitable for desktop use
  • Support for 2 prop pitch motor rotators
  • Potentiometer for the direction indicators
  • Software for ease of modification and expansion
  • Remote 24 VDC power supply for the motor

There are commercial products that will do all of this and much more. But it's more educational and interesting to build my own. It is a project that is within the abilities of many hams, although for some, I must admit, it may be daunting. I always seem to struggle with circuit design, while software is one of my areas of expertise. 

The downside of this project was the time and effort expended. I didn't do it to save money! I did it for the learning and personal satisfaction. There is no shame in buying a controller if you'd prefer to apply your energies elsewhere.


Let's begin at the back of the controller. Although an unconventional place to start, it can be illuminating to first look at the interconnections. The USB port is on the Arduino Uno board. It is only needed for uploading and testing software. All power comes from the 13.8 VDC connector on the lower right. A barrier strip provides ±15 VDC for the two direction pots and the two pot wipers.

The DE9 connector connects to the power supply unit. 6 pins are for low side switching of relays: 2 to control AC and 4 for the CCW and CW DC relays of the two motors. Switching is low side, requiring one pin supplying +12 VDC to the relays and external circuitry. Ground is via the connector shell, which therefore requires a shielded 9-pin cable.

One unfortunate lesson was that the DE9 connector doesn't project out far enough to seat the male cable. The ABS panel is too thick. After the picture was taken I had to carefully extract it and place the flange on the outside of the panel. Although it isn't as pretty it is only rarely seen. Thankfully the wires were terminated by Dupont connectors rather than soldered so it didn't take long to make the change.

At the moment only one of the AC pins is used since there is one power supply that only has enough current capacity for a single motor. That means only one motor can be turned at a time. That is enforced by the software so there is no risk of blowing a fuse. With a second power supply and software update both motors could be turned at the same time. 

The 2 remaining pins are for monitoring the DC current and voltage. Those functions are not present at the moment even though I have the modules. The quantities will be displayed when a motor is powered, and also used to detect and respond to system faults. I have been bedevilled in the past by wiring and component failures that required opening up the controller to attach current and voltage meters. The built-in voltage and current monitors will make problems easier to diagnose.

There is very little heat produced by the controller. I tried to place most of the heat generating circuits near the back vent. Voltage regulators are the main culprits.

This is a view of the interior before the display and circuitry and their respective cables were installed. The 5 VDC regulator is up against the vent. A chain of diodes reduce the 13.8 supply to the 12 VDC maximum that the onboard Arduino regulator can handle. On the left wall is a buck-boost power supply that produces ±15 VDC for the direction indicator circuitry. They can be found online and they are cheap. There's no point providing a link since these products come and go quickly.

The buck-boost power supply is one source of heat. Because the minimum output is 30 ma for both the positive and negative supplies, unless the connected circuits draw at least that much it is necessary to install 470 Ω resistors to bleed the minimum current. Otherwise the output voltage can soar to over 50 volts. The power supply module is cheap but it requires care in how it is used.

 Since it is not usual to disconnect the direction pot wires or even the internal cable harness to the op amp circuit, a higher value resistor that draws less than 30 ma and produces less heat entails risk. Each resistor dissipates about ½ watt at 30 ma. There is one for the positive and negative supplies. They get very warm, too warm to touch comfortably. I may replace them with higher power resistors on the back wall of the enclosure to be near the vent.

Various versions of the Arduino Uno can have different dimensions. That could be a problem for locating the USB connector on the rear wall and PCB mounting holes. I suggest buying the board first and measuring it before picking up a drill and saw. Having at least one spare of the same type can avoid future grief. The Uno was the smallest Arduino with the GPIO complement to support this project.

The display is a 1602 2×16 LCD. As I described in an earlier article I had difficulty finding a template that worked well for 3D printing a bezel that wasn't too large and that secured the display to the front panel. I abandonned the search and carefully cut a rectangular opening in the front panel that is a press fit for the display. Some fussing with a file helped to make it as snug as possible. Hams with 3D printer skills could do better. Nevertheless it doesn't look too bad from a meter away.

The small holes below the LCD are for adjusting the zeroing pots. The gain pots are on the central PCB. The gain pots should not require adjusting after initial setup. I also included software gain controls to fine tune the gain more conveniently. With one chain drive motor with a 1:1 turn ratio and an outboard pot on the direct drive motor with about a 2.5:1 turn ratio, hardware gain is preferred to keep to the op amp circuit's linear range. If the hardware gain is too low the resolution of the bearing may suffer due to the 10-bit ADC on the Arduino boards (1024 discrete values).

In this picture most of the components are installed. The major additions are the support for the zeroing pots and the PCB with the circuitry. The circuit includes connectors for the DE9, power, GPIO pins, LCD and zeroing pots, trim pots for the LCD contrast and two for the direction indicator gain, and op amps for the direction indicators. There are RFC and bypass capacitors for external connections.

These are the completed units. The controller has evolved with the addition of the 4 buttons to operate the rotators and a small Arduino shield (plug in) with a ULN2003A NPN Darlington array to switch the 6 relays. To conserve analogue GPIO pins (I use all 6 on the Uno) only 2 are used for the buttons. The pins are pulled high when idle, grounded for CCW and half-Vdd (2.5 VDC) for CW. The direction control buttons are debounced in software.

There are a lot of wires and connectors inside the controller. A better designer than I'll ever be may have been able to clean it up. The circuitry is simple but it appears complicated due to all the wiring harnesses. Working on the controller is not as bad as it looks. Documentation is vital.

The power supply is an ugly unit that came with one of the prop pitch motors I acquired. That's fine since it is located out of sight under the operating desk. The chassis was stripped of most components since they were for the discarded manual control system. 

A large electrolytic capacitor was replaced by a new and much smaller 2200 μF 50 WVDC unit. The barrier strip is for the CCW and CW 24VDC connections to the motors. Ground (motor common) is a chassis stud where the black DMM lead is attached. The DE9 connector is supported by small aluminum angles that I made.

A fuse holder (5 A) was placed on the side in an already present chassis hole. Not quite visible is the AC power switch on the front (bottom left). It can be left on since AC only flows when the rotators are turned; it can be turned off for software testing. I am using this power supply rather than the old one since this one is stiffer. Under load it produces 24 to 25 VDC. It is reduced by a couple of volts at the motors due to wire resistance. The motor on the 15 and 20 meter upper yagis is starting and turning faster with this supply, and I expect more reliably in the winter cold.

Automotive 30A SPDT relays are mounted on the power supply chassis, 4 switch DC to the two motors and one under the chassis switches AC to the power transformer. I was remiss in not ordering relays with an internal protection diode so I included them on a small PCB along with bypass capacitors for the control lines. More components will be added to the PCB for new features. There are a lot of wires just because there are many relays but the circuit itself is uncomplicated.

To avoid switching high current DC the relays are sequenced by the software. When a button is pressed, the corresponding DC relay is energized, followed a fraction of a second later by the AC relay. The sequence is reversed when the button is released. Although the relays are rated for 30 A, their lifetime will be shorter when switching high current. Typically the motor starting current is limited to less than 20 A due to the resistance of the long wires to the tops of the towers.

With each component tested it was time to connect the controller to the prop pitch motors. Or, if you like, integration testing. 

To avoid overly disturbing the existing controller and its fragile direction indicator circuitry, I started by moving the motor wires to the new controller but not the direction pot wires. The new controller was set to power the motor while the old analogue prototype continued to indicate direction.

The only hiccup was that I'd reversed the CW and CCW wires. It's an easy mistake to make with these motors and my labels were not the best. All was well and even better since the motor for the 20/15 meter stacks started and turned faster with the new motor, just as I'd anticipated. For some reason it is particularly sensitive to low voltage.

For the next step, the direction pot leads were transferred to the new controller. Of the 6 wires, 4 go to the ±15 VDC terminals and the other two are the pot wipers. 

Tranferring the wires was a lot trickier than for the motor. Since the direction pots don't have the same turning ratio to the mast (as described earlier) it is vital to connect them to the correct circuits. I pre-calibrated both circuits manually with a directly connected pot -- both hardware and software gain controls -- so that the yagis wouldn't have to be turned too much for the live calibration. Zeroing was easily accomplished by turning both rotators north before moving the wires.

I did a poor job of documenting the transfer and documenting the internal cables in the new controller. After several false starts I finally got the mess figured out and retested the calibration using a local pot. Finally I got it working. This took several days because I needed time away from the project due to excess frustration. It was easy to find other projects to play with in the interim.

When I had another go at it I discovered the problem. The controller was fine. It was one of those absurd coincidences that the direction pot on the 20/15 prop pitch motor was slipping. That's one more item added to my to-do list. I have a new bracket already made that I was negligent about installing. I guess this is an opportune time.

Rather than light the LED inside the button (which is covered by your finger) I use blinking arrows next to the bearing indicator. It's rudimentary but effective. 

Among the problems I've encountered with the controller is electrical noise. The diodes on the relay coils are mandatory, as I discovered, since when they disengaged the LCD or the Arduino would often fault. Even with the diodes there are problems. Switching of the AC supply line occasionally scrambles the LCD but not the Arduino. It can also cause the needle on one of the Hy-Gain rotator controller to momentarily jump.

I am working to resolve these issues. Digital circuitry is very sensitive. A metal enclosure might have helped. All I can do is add more bypass capacitors, shielding and RF chokes to manage the intermittent faults. Until I get it fully under control I occasionally reset the controller. The easiest way is to pull the power connector (there's no on-off switch).

I should briefly mention the software I wrote for the controller. The direction indicator and motor control function independently. I've already discussed the direction indicator circuits in some depth so I won't say more about it here. 

The motor controls feed a finite state machine (FSM) that determines the state of the motor controller based on button input and timers. There is just one FSM since it is disallowed to turn both motors at the same time with the one power supply.

An early draft is on the right. It's to give a taste of what an FSM is for those unfamiliar with it. So don't worry about it being somewhat cryptic!

There are pending states to ensure solid button presses and releases, which act as button debouncers. It is highly undesirable to have the relays snapping in and out due to intermittent button operation, whether by the operator or button contact issues. Therefore there is a brief delay between the button press and motor operation. 

Sequencing of AC and DC relays is driven by FSM states and timers. Once the motor is turning all the other buttons are ignored. Only when the active button is released are other buttons inspected. To prevent operator errors the controller waits for all buttons to be released if one of the others is pressed when turning stops.

Since the direction pots are independent there is no protection against over-rotation. It was more important to get the controller usable rather than first address every edge case. That will be corrected in time.

That leads to future feature implementation. The first version is rudimentary but perfectly functional. It may be enough for me to use but not for guest operators. Additional protections and displayed information would be beneficial. Planned features include:

  • Over-rotation protection. A small amount of over-rotation is desirable and I've made the rotation loops tolerant of it. Perhaps 20° but no more. 
  • Edit direction pot glitches. Pots are imperfect devices when out in the weather. The wiper does not always solid contact the wire coils as it moves. These glitches can be identified and dealt with in software if they are not long duration. Inertia of the meter needle on legacy controllers similarly smooths the bearing indication.
  • Current and voltage monitors. Once the modules (very inexpensive to purchase) are added to the power supply it will be convenient to monitor these key indicators of motor operation. No more pulling out the DMM for testing. The data can be used to automatically stop operation if the motor does not start or turn properly, or to warn of a broken connection.
  • Two power supplies. I'd like to be able to turn both motors at the same time. This would be most helpful for multi-op contests. I prefer to mount both on a single chassis, including the control circuits. This feature is mainly a software change.
  • Wireless PC connection and control. This will allow rotator control from the PC, either by a separate application or integration with contest logging software. It is also needed should I ever implement remote operation of the station.
  • Over-rotation protection, as described earlier in the text. 

In the end, was this a worthwhile project? I am undecided. Of course I learned a lot and there is satisfaction from having done it, but the usability is perhaps not as good as I'd like. The box looks cheap, feels flimsy and it is so light that the cables at the back can lift the front feet. Although it is working fine there are transient issues to track down and further software development is needed to add the missing (and desired) features.

With all the projects I undertake this was perhaps not the best use of my time and effort. I started it more than a year ago and even though I spent only a fraction of my time on it, it's been annoying to constantly see the unfinished controller sitting there. 

I will put this project aside for now since it works. My focus for the rest of the year will turn to other projects. I have no regrets but building is not always superior to buying. Especially so as one grows older.

The old controller with the prototype direction indicators is now officially retired. I'll salvage the 24 VDC power supply and send the rest to my junk box.

Saturday, June 7, 2025

The Curious Challenge of FFMA

For those that don't recognize the acronym, FFMA is the Fred Fish Memorial Award. The objective of the award is simple: confirm contacts with every grid square in the continental US on 6 meters. There are 488 of them. Difficult? Oh yes! DXCC on 6 is much easier. As of this date there are just 57 awardees.

I do not chase grids. The corollary is that I do not pursue FFMA, or any award for that matter. My interests on 6 meters are DX and unusual propagation. That hasn't always been true. When the Maidenhead system was new decades ago I was, as now, a 6 meter enthusiast. During the period from 1985 to 1992 I happily chased grids on 6. It was easier than DXing since my operating time was limited, activity was almost all on CW and SSB, and most of Europe and the rest of the world had no privileges for 6 meters. DXing on 6 is much easier today!

Out of curiosity I dug up the ARRL grid square map on which I highlighted worked and confirmed US grid squares. Keep in mind this was done on CW and SSB without spotting networks. Many of the QSOs were more than "599 FN25" exchanges. It was a different era.

There are non-American grids marked even though the supposedly "North America" map has just a sliver of the continent outside the US borders. But it's good enough to illustrate what I worked up to 1992 -- I went QRT for 20 years subsequently and returned to 6 meters 10 years ago.

The paucity of western grids is due to population density and the relative rarity of propagation beyond the usual single hop sporadic E range of about 2000 km. Since I didn't have many opportunities to work DX outside of the 1989-1990 solar cycle peak (that was a good one!) it was natural for a 6 meter enthusiast like myself to pursue grid squares.

I quickly assembled the second map with the confirmed grids from the LOTW (Logbook of the World) FFMA award page. This time I drew a line above the US grids and didn't mark other grids. I have 388 out of 488 FFMA grids confirmed on LOTW. I may have cards for more but I don't count those (or even look at them). That's a pretty good total for someone who focusses on DX and doesn't chase grids.

There are fewer gaps than I had in 1992 even though none of my confirmations from back then were carried forward. That is, all contacts were made in the past decade, and are heavily weighted to the time after I migrated to FT8. Missing grids in the northeast or within E hop distance are due to disinterest rather than a lack of opportunity.

One curiosity that was brought to my attention a few years ago is that you can work Canadian and Mexican station on those border grids for FFMA credit. That surprised me! Yet that is indeed what the rules say:

(c) Any portion of an FFMA grid may be worked for FFMA credit. It is not necessary for an FFMA operation to be on US soil; operations from Canadian or Mexican territory or from water within an FFMA-required grid are acceptable.

It seems odd that non-US contacts would count towards a very US-centric award. That explained why I was so popular with award hunters. Although there are quite a few of us on both sides of the border, I appear to have the biggest 6 meter signal from FN24. I have received several sked requests which I try to satisfy. Non-DX stations may have difficulty getting my attention otherwise.

Well, that's enough of an introduction. Now I come to the big question: why on Earth would anyone chase this award? It's really really hard -- a potentially decades long pursuit. Not only are the openings to far flung grids uncommon, many of the rarest grids are only workable when a ham roves to those grids, as a favour to chasers, and only if their operations coincide with an opening. I am not surprised that the number of FFMA holders is less than those on the DXCC Honor Roll.

Those near the centre of the continent have an advantage since most of the country is within one E hop. It isn't necessarily that easy since grids in the skip zone, and there are many of them, can be difficult to work. Worse, if those grids are rare and only activated by rovers, the signals of their portable setups might not be good. An aurora (at northerly latitudes) or tropospheric enhancement are welcome but unlikely to coincide with an activation.

Many are happy enough to collect grids, any grids, not only those 488. Every opening brings an opportunity to add to the total. A subset of those will track their FFMA progress and call the needed stations when they're heard, but will not make a serious effort. Only a few go the extra distance. You have to make skeds, join groups where grid-peditions are planned, ask others to activate needed grids, and then confirm the contacts that are made.

I usually don't bother to call rare grids when I hear them (see them on WSJT-X). If they have a pile up I would rather spend my time hunting for DX openings. I simply move on. 

In one case I have the needed list from one friend who is moderately serious about FFMA. If I hear what appears to be a rare grid I'll check his list and contact him. He's whittled down the number of remaining grids this way, moving him a few steps closer. I hope that he is eventually successful. The list isn't long yet it will take him years to get there, if at all. You have to enjoy the chase since few reach the finish line.

FFMA is one of those awards where you must work every entity. This is like reaching the top of the Honor Roll, a clean sweep in the Sweepstakes contest, all zones in CQ WW, or all counties in a QSO party. I don't find that interesting. My objective is to maximize my score or entity count without an unreasonable investment of time and effort. A lifetime investment to achieve DXCC Honor Roll or FFMA holds no appeal. Many would disagree, and that's their prerogative.

Now that sporadic E has once again arrived there are quite a few grid-peditions on 6 meters. I may call them if they're on the other side of the continent and therefore fall within my idea of what constitutes DX on 6 meters. Sometimes they call me if conditions are poor and they are hungry for contacts. These hams have the same enthusiasm for difficult QSOs on 6 and will work what they can. They don't only call CQ!

For everyone chasing FFMA or similar difficult awards, I salute you and sincerely wish you the best of luck. But I won't join you in the chase.

Wednesday, May 28, 2025

Raising the 40 Meter Reversible Moxon

One month ago I discussed the construction of the 40 meter reversible Moxon. With the advent of NEC5 it became possible to develop accurate models of complicated antennas like this one. These include tapered elements, mid-span capacitance hats, and close spacing of elements. NEC2 and NEC4 cannot properly model this antenna without a great deal of effort with segmentation or to calibrate the incorrect calculations.

Well, that's the theory. Others have had success using NEC5 to develop models that closely match measurements of built antennas, and my initial experiments were promising. It is no trivial matter to build and test an antenna of this size and then use real-world measurements to revise and try again. Trial-and-error may be an acceptable strategy for small yagis and wire antennas but not for rotatable 40 meter yagis.

For those that prefer one article that encompasses the theory, construction, testing and performance of this unusual antenna, all I can say is "sorry". I am writing this up as I go and each stage from conception to on-air use is an interesting subject for a blog article. This blog has always been about the journey, not the destination. 

So, now that we've covered the conceptualization of the reversible Moxon, the model and most recently its construction. we proceed to the next step: raising it onto the tower. The unique attributes of the antenna complicate the process, especially for side mounting on a guyed tower. For those with a self-supporting tower and no obstructions within the footprint of the antenna (43' × 37'; 13 × 11 m), raising it is a simple matter: assemble it around the tower and pull it straight up. It is not so straight forward with a guyed tower.

Moving fast

As I stated in the construction article, time was of the essence. The yagi was sitting in a hay field and the hay had entered its rapid growth phase. One way or another I had to get it out of there. I intended to raise it earlier in the month but, as usual, higher priority jobs got in the way. Finally I the antenna was completed and ready to go on the tower. Then it became unseasonably cold, windy and rainy. 

I pointed a finger at the calendar on a day with no rain forecast and decide that would be -- must be -- the day. I contacted friends and soon had a crew ready to come over for the big event. They were Alan VE3KAE, Dave VE3KG and Vlad VE3JM. If you're a contester the last two calls may be familiar.

I rigged the tram line and other mechanisms on the tower and antennas one day in advance. I say "antennas" because the XM240 had to come down first.

Lowering the XM240

Luckily these antennas have short booms: 22' for the Cushcraft and 20' for the Moxon. There was a gap of just the right width between a tree and guy anchor (for the 140' tower off to the right in the picture below). There also was a tree perfectly centred in the gap to anchor the tram line winch. We chose manual power since we had enough people and gravity helped for taking down the XM240. It can be difficult to speedily communicate with a driver of a vehicle that can easily damage a fragile antenna that at some points must be moved inches, or less.

Lowering a yagi is not without drama. You are never quite sure whether you have the CoG (Centre of gravity) where you think it is, and with a 75 lb antenna you may not be able to easily make adjust the harness after it is unclamped from the mast. The XM240 is pretty well centred on the boom-to-mast clamp so I wasn't too concerned. However, the lever arm and rope I attached to the boom caused a slight tilt that we needed to closely monitor. The capacitance hats are fragile and it is far too easy for the long elements to snag a guy. Good communication between tower and ground is needed to accomplish the necessary choreography.

The lever arm is used to tilt the elements up as needed to clear the guys. Since I was on the tower near the antenna I had the best perspective to guide the crew handling the haul rope, the lever arm and the winch (tram line tension). With a series of rapid commands back and forth we were able to guide the yagi past the guys without any drama. It helped that one of my friend's set me up with a VOX-actuated HT clipped to my harness.

Rigging the Moxon

Unlike a typical yagi, the Moxon elements are joined at the tips. That imposed constraints on the rigging and operation of the tram line. There was also the challenge of guiding the antenna between the guys directly below the tower side mount and the TH6 above. The tri-bander was not so much higher that the upward tilt of the long 40 meter elements would not reach it. The many clamps and traps on the TH6 can and did snag the Moxon elements.

The major consideration for rigging the Moxon was whether to run the tram line over or under the rear capacitance hats. I decided to run it above the tips since that would help to keep the antenna oriented upward, which was needed to clear the guys. That is, the tips or the connecting fibreglass rod could rises no higher than the tram line. I used a ½" rope rather than steel cable for the tram line despite its greater elasticity since it was less likely to abrade the antenna. Some contact was inevitable.

The choice seemed reasonable and it worked as intended with respect to that one issue. Unfortunately it turned out to be a poor choice because there were greater concerns that I failed to account for in my rush to get the antenna out of the hay field. It was only after it was attached to the mast that I realized how seriously wrong my choice had been.

First, I'll note that it took 3 attempts to successfully pull the Moxon up the tram line. On the first try it failed to clear the guys. We added the lever and rope so that ground crew could steer the antenna. The second attempt failed because the weight of the rope on the lever tilted the antenna too far upward. Finally we got it more or less right. Well, right enough to guide the Moxon where we wanted it to go.

I took the picture at right when the forward capacitance hats reached the tower. You can see the tram line, haul rope and the rope dangling from the boom lever. After taking the picture I opened the tips and guided them around the tower. Pulling resumed after I reconnected the tips.

It was at this point that trouble arose. The angle of the antenna caused a collision of the forward hats and element tips with the TH6. There was no provision for tipping the boom more level to clear the elements of the higher antenna. The lever was still out of arm's reach. It is normal for the trammed yagi to increase its vertical tilt near the top of the tram line due to catenary physics: the proximity of the pulley carrying the weight increases the downward angle of the tram line at the tower anchor. I could have reduced this using steel instead of rope, however that entailed the risk that I described above. 

A further increase of tram line tension helped enough that I could jiggle the ropes to encourage the Moxon past each clamp and trap on the longest TH6 elements. Clearance was easily completed when my arm could finally reach the boom and lever.

We slacked the tram line and the Moxon's boom rested against the mast. The haul rope was tied off when the boom was centred on the mast clamp. The u-bolts and saddles were then installed. That's when the more serious problem was discovered. 

It was when I couldn't level the antenna with the lever arm no matter how hard I tried. I looked behind me and discovered the mistake. Have a good look at the picture above. Perhaps you will see the problem without me telling you, especially since I gave a strong hint earlier in the article. Now that you, hopefully, see it, I'll continue.

When the boom is rotated the rear tips strike the tram line. My attempt to rotate the boom pushed the inside ends of the capacitance hats downward. This occurred due to another mistake: I forgot to torque the nuts of the u-bolts on the element clamps. They were intentionally left snug but not fully tightened so that I could align the tips once it was cleared the ground. The antenna had been abandonned in the hay field for so long that I forgot. 

Although I couldn't fix that problem, it didn't overly worry me. The mechanical risk of failure is low and the impact on antenna performance would be negligible. In the former case the fibreglass and aluminum are flexible enough to survive. In the latter case, performance of an antenna is largely determined by where current is highest. The attitude of the tilted capacitance hats has the same loading effect and will still cancel the fields with each side of each hat and pretty well with the hats at the other end of the elements. The distance between hat tips is critical and that remained unchanged.

My big worry was removal of the tram line. I could either let it go from the top or pull the full 200' length up and over the capacitance hats. I judged that the risk of damage was far greater by releasing the top of the tram line since the rope's weight would whiplash the rope tip as it wrapped around the fibreglass at high velocity. I opted to pull the rope up and over instead. That worked well enough in that no more damage resulted.

A broken fibreglass rod is cheap to replace but expensive in time and effort. Since I expect to pull the antenna down in the fall to inspect and change the antenna according to how well it performs during summer storms, I may leave the curved hats as they are until then. However it's an interesting problem that had me considering a repair. I think I know how to do it. Perhaps it'll be the subject of a future article!

Finishing off

I decided to use the custom boom-to-mast clamp that came with the XM240 rather than I one I selected. It was more robust, already installed and it was aligned with the rotator direction indicator. I can make another for either the Moxon or XM240 when it comes down in the fall.

I kept my friends longer than planned so we quit for the day. Operating the winch and hauling up a 105 lb yagi is tiring work. All of us needed a break.

The next day I climbed the tower to test the antenna and connect the rotation loop. The coax to each element feed point are equal length should I ever be motivated to stack it with the 3-element yagi on top of the tower. Their lengths have no effect on Moxon performance. I made them longer than required so I coiled and taped the excess to the boom for the lift. 

Notice the very slight droop of the boom. That 20' long schedule 80 2-⅜" OD 6061-T6 pipe is strong. It was worth the weight penalty. I also happen to find it amusing that the elements are trussed but not the boom. 

All of the coax connectors were weatherproofed but more could be done for the feed point enclosures, relay keying wires and securing the cables to the boom.. Only one wire is needed to operate the reversing relays since the return path is via the boom and coax and tower. In my station I bond the grounds for DC, RF and ground rods.

Here you can see how I mounted the small box with the coax switch. I was careful to label all 3 boxes and the boom to indicate the driven element and reflector for normal orientation (relays using their NC contacts) to ensure the correct connections are made.

Before weatherproofing I measured the SWR by connecting the normal driven element to the analyzer. Compare it to the NEC5 model. That's pretty good agreement! Even though there are interactions with the guys and the TH6 above it, the wavelength is long and the TH6 coupling small since they are pointed the same direction. 

Perhaps more important than the low SWR was the frequency where it was lowest. That agrees with the NEC5 model within 10 or 15 kHz. That raises my confidence that the design frequency range was achieved in practice. That success is a testament to the accuracy of NEC5 modelling a antenna featuring stepped diameter tubes, capacitance hats and close coupling between their tips. Neither NEC2 nor NEC4 are up to the challenge. 

Performance verification will have to wait. During installation a wire must have been knocked loose so that the rotator turns in one direction but not the other. That left it locked west. I operated in the CQ WPX CW contest with it in that condition. It worked well but I don't yet know how well in comparison to the 3-element yagi. There was no difficulty transmitting with a kilowatt. The SWR barely changed with the Moxon pointed west and the TH6 pointed south. That was encouraging.

I had no time available to trace wires to patch a path back to the shack for the reversing feature. That will also require a software change to my custom antenna selection software. Due to enforced rest after routine surgery this week I likely won't get to it until at least mid-June.

Aftermath

The urgency to clear the hay field prevented completion of this antenna project. At least the antenna is on the tower and working, which is a great relief. Until it is complete and its performance properly assessed I am delaying the discussion of how I built and tested the switch boxes. An article covering performance and electrical construction will eventually appear, though I can't say when.

On a more practical note, I lost my 17 meter antenna. The XM240 is near resonance on that band so I've been using it that way since I don't have any WARC band antennas. The 18.1 MHz SWR on the Moxon is near infinite. After testing various antennas with the antenna analyzer I chose the 80 meter inverted vee as my 17 meter antenna. Its SWR is 1.5 across the 17 meter band. It works well enough that I've already logged one DXpedition. The pile up was small so its performance is difficult to assess at this time.

This is an opportunity to reflect on the lessons learned, from design through to raising of the reversible Moxon:

  • NEC5 rocks! Although it can be slow due to the greater number of segments it typically requires, its ability to accurately model complicated antennas like this one is remarkable. It integrates nicely with EZNEC, which also supplements NEC5 with additional features such as insulated wires which NEC5 alone does not support. NEC5 is well worth the licensing fee.
  • Double check all fasteners. While this is obvious it is easy to forget when one is in a hurry. 
  • Ground crew get rightfully annoyed when you ask the seemingly impossible or at least improbable. It is easy to forget the strain they're under while holding a massive antenna in position while I fiddle with the mounting hardware. You should have heard the language when I asked them to raise the antenna exactly ½" so that I could drive in the last u-bolt.
  • Label and record every control wire in the station, no matter how unimportant. I have countless runs of Cat5 and other cable for the dozens of control lines, including antenna switches, stack switches, antenna mode switches, rotators and more. I'm pretty good about labelling the cables and recording the details but there are gaps. Hence the need to do wire tracing. I'm now taking the opportunity to revise and expand my records.
  • Running the tram line under the rear capacitance hats would have been the better option. I failed to think through the entire process from lifting the yagi, riding the tram line, fitting the antenna to its mount and then, critically, removing the rigging. Counting on luck is no excuse for taking short cuts. 

Despite the frustrations and mistakes the antenna works. I'll know more about how well it works after I repair the rotator and complete the reversing feature.

Photo Credits: Other than those I took on the tower, pictures in this article are by VE3KAE and VE3KG.

Thursday, May 22, 2025

6 Meters Sputters to Life

I am disappointed to observe that 6 meters has a season again. While the solar flux marched higher in 2024 there could be openings on 6 at any time. Yes, there was still some seasonality affecting F-layer MUF but there could be excellent DX openings almost any day. And there were many! I lost several opportunities for long haul DX that may be gone for good in this solar cycle because the Sun in 2025 is no longer cooperative.

Which brings us to summer sporadic E. This year's may be better than it has been for the past 2 years since there appears to be a weak anti-correlation between solar activity and sporadic E. That is, you get great F-layer openings or great sporadic E openings but probably not both at the same time. Nevertheless, unusual long distance paths can be formed by linking sporadic E with tropical TEP

The summer E season has certainly begun. We had our first 6 meter openings to Europe, the west coast and the Caribbean over the past week. These will become longer and more frequent until the usual peak at the solstice in late June. Shorter, single hop E openings have become common here, in Europe and in Asia.

Regular readers will know that I have little interest in "local" 6 meter contacts. I will occasionally work single-hop contacts, however my focus is almost exclusively on DX. When I call "CQ DX" on 6 meters don't be surprised that I don't answer non-DX -- that's my expressed intent, not rudeness. I am not willing to spend my time trying to please everyone and not myself. 

That said, I may answer. When I'm CQing into a potential but not an active opening, it's to discover if I can raise flags on PSK Reporter in distant locales. Since any transmission will do for that, it doesn't matter whether I CQ or have a QSO. 

So far...

In May we had our first openings to Europe, Africa and the Pacific, along with the more reliable paths to the south. Perhaps it's sporadic E linking to TEP, but I really don't know.

The majority were stations I've worked before, including D2UY and 3D2AG. I tell my friends and keep listening for new ones. The frequency and strength of sporadic E openings will increase over the coming weeks. While that is certain, it may or may not deliver interesting DX.

Despite what I've heard, the spring season has been disappointing so far. At least from here; others have had more success. Unlike spring 2024 the MUF for F-layer propagation has been too low. I listened but mostly it was just the usual propagation to southern South American stations in CE, LU and CX, with the occasional PY and HC. I love working them, since they are long haul DX, but other than for grid hunters (which I am not) they are nothing new. 

Several of us were excited to hear the TX9A DXpedition on 50.313 MHz in early May. We had few opportunities when they were successfully working North American stations well to the west and south of us. I heard them on two consecutive days, May 5 and 6. The screenshot was taken on May 6 during the peak of the opening at my station.

As you can see it was very marginal, with several strong peaks and deep long fades. I tried and failed. Had they responded to me I wouldn't have known. The chase was enjoyable despite proving fruitless. 

Another that got away was PJ7EE. Several of my friends worked him for a new one. I missed out because I was out of the shack. By the time I returned the opening was fading and I couldn't get through the pile up in the few minutes I had before he was gone for good. This one is not so rare that it won't get into my log eventually.

The African openings have all been marginal. One day D2UY was very strong but otherwise signals have been exceedingly weak. There are of course many countries in Africa on my wanted list. At the same time D2UY was heard, others on the east coast were hearing or working TR8CA, 9J2FI and others. I heard a few calling ZS8W but I heard no one working them. Closer Africans such as EA8 and D4 have been heard recently so the easterly path to Africa has returned and should improve. 

I need good propagation and DXpeditions to work most of Africa. Several 7Q were worked last year thanks to the effort of 7Q6M to train and license several young Malawians. It's good to hear them with some regularity. It shows what is possible were there more activity in that vast continent.

Automatic operation

It should be no surprise that the presence of robot operators is increasing on the digital modes. 6 meters is not immune. I have heard rumblings that more effort will be made by awards issuing bodies that disqualify robot QSOs. It'll be interesting to see if this happens and how it can be policed. Suspected offenders include several notable DXpeditions. 

I use the filter feature in WSJT-X-i (improved) to remove suspected robot operators from my monitor screen. Although I can ignore them, the filter clears the screen of pages and pages of CQing robots. The filters help me to easily find the DX station messages without having to scroll through pages of robot muck. 

I don't care whether robot operations are legal, sanctioned or justified by arcane theories and opinions. They interfere with my operating pleasure so they are filtered or otherwise ignored. The filter list is frequently updated as robots come and go.

As more stations give 6 meters a try, it is expected that the same operating practices follow. Higher activity has its pros and cons. I make accommodations to deal with what I consider poor behaviour. Taking advantage of the available tools is more productive and satisfying than becoming angry or frustrated.

Prospects for F-layer propagation

Unless we get a double peak this solar cycle the prospects are not good. It's possible though I am in no position to make a prediction. If it does happen it won't be any later than this fall; solar cycle 25 will almost certainly be in decline by 2026. Fall is a great time of year for a high solar flux since seasonality enhances the MUF to increase the probability of 6 meter DX. Last fall's openings may be it for solar cycle 25. Southern Asia, for instance, is almost unworkable for us without strong F-layer propagation.

Even if F-layer can't do it alone at this high geomagnetic latitude we can look forward to occasional path linkage. Local sporadic E propagation can link to TEP and other F-layer modes and create elusive and brief worldwide DX openings. These can be hoped for but not relied upon. The linkage is more likely during the June-July sporadic E peak to the southern hemisphere due to the higher F-layer MUF at tropical latitudes. After 2025 we may lose that and must rely on links via TEP.

I really can't say any more. We can only monitor and hope for the best. Solar modelling and related predictions are not reliable enough to reliably inform us what will come. We have to listen. Beware of those who misinform with predictions that tell you what you want to hear. We should strive to do the best we can with the hand we're dealt.

The buddy system

We have a small group of local 6 meter DXers that shares news of openings via an email reflector. I believe that with the latest addition there are now 6 of us (an appropriate number). We benefit from helping each other, ensuring that none of us miss much; it's like growing several extra sets of ears. We've all worked new countries by receiving alerts from our buddies.

I've been both hot and cold on the value of the venerable ON4KST web-based 6 meter chat. Some years I don't sign in at all and other years I've been a regular participant. I won't get into the reasons here. If you don't have other 6 meter enthusiasts nearby with whom to form a group you should definitely look into using ON4KST chat. At its best you can really "hear" the pulse of the band and coordinate QSO attempts with others, sometimes in countries you'd love to work. 

Since sporadic E spotlight propagation is common on 6 meters, the members of your group should be nearby. Our group's members are in FN14, FN24 and FN25. Despite our proximity, quite often not all of us hear the same DX stations.

DXCC prospects

The poor likelihood of more F-layer propagation this solar cycle limits my ability to add to my country total. I now stand at 146 worked and 134 confirmed. I've worked just one new country so far in 2025. The reach of sporadic E is inadequate to make up for the loss of F-layer DX paths. I spoke about diminishing returns several years ago and it's only become worse. The new countries come more slowly now.

I often have to rely on DXpeditions to the countries that I need, and that are within the scope of possible propagation paths.When they happen I need a little bit of luck as well. My antenna system could always be improved, but it is already good enough to hear and work weak signals that others in this area cannot. A better 6 meter antenna system is not (yet) high enough on my priority list to incentivize me to make an effort beyond idle speculation about alternatives.

I'll be monitoring as often as possible over the coming months to take advantage of whatever propagation comes my way. If I can put 5 new ones in the log this year and thus surpass 150 countries worked I'll consider it a good year.

I wish the best of DXing luck for all of you who are as seriously infected with the 6 meter bug as I am. My infection has lasted 50 years and shows no sign of abating.