donderdag 31 juli 2025

Prototype of the home designed alu plate arrived

Once again, a small stone has been laid in the river of ongoing projects: an aluminum plate, designed by myself, that aims to solve the shortcomings of the mini-tiltplate.

Although the tiltplate plays a crucial role in my station for antenna selection, it comes with several limitations:

  • Each type of Yagi boom requires a different solution. Usually, the boom can be mounted inside the tiltplate, but for certain types—such as the 80mm square boom—more complex technical workarounds are necessary.

  • Aligning round boom tubes is a slow and painstaking task.

  • For larger antennas, my mini-tiltplate is inadequate due to a lack of sufficient mounting points.

  • When a vertical boom truss is required, the mini-tiltplate offers no solution.

After much thought, I’ve come up with a solution that addresses all these issues: an adaptive aluminum plate that fits the chosen antenna perfectly. It is pre-mounted on the antenna boom and can be easily connected to the tiltplate using seven M10 bolts, with respect to the karlock security system. 

Ensuring that the antenna hangs perfectly horizontal is now achieved with two adjustment screws spaced at the correct distance—no more hoping that things will align properly once airborne, but rather having certainty in advance. That makes a real difference.

My first prototype plate was delivered this week.






Fixed vertical positioning, independent of the used antenna.


Original mini tiltplate.



This plate can easily accommodate both the OB5-10 with a round boom in combination with the SteppIR, as well as the OB2-40 with an 80mm square boom.


The Dutch company (www.lasopmaat.nl) that cut the plate works with input based on a DXF file. It was a bit of a throwback to my mechanical AutoCAD drawing days—over 30 years ago—to get this drawn. LibreCAD is a free piece of software that can generate this type of file.

The result meets all expectations. I was a bit nervous checking whether any measurement errors had slipped in—but fortunately, everything turned out perfectly.

The next step is getting the Yagi back in the air.

This opens the path for the use of several bigger monoband antennas that can be installed within minutes.

maandag 21 juli 2025

IARU 2025 as operator in the OP0HQ team

Twenty years after my first participation in the national OP0HQ contest team—back then with ON4UN on 40m CW—I unexpectedly found myself part of the national team once again. This time, I was responsible for 10m SSB. Last year, I had already used this band slot to test the Optibeam5-10, which resulted in a very disappointing 250 contacts and the impression that conditions were exceptionally poor.



This year, propagation on 10m was even worse, and I only managed to log 271 contacts. Admittedly, there were a few nice ones from the African continent and South America, including the Falklands, but not a single contact with the USA or Japan. The trend was similar across all competing headquarter teams, but as usual, zone 27 was hit the hardest. It’s tough to transmit for so long with so little to show for it.

Shack improvement almost done

 

The shack upgrade is now nearly complete. 

Installing and integrating the various devices from the FlexRadio/403A family has so far been accomplished with just a few mouse clicks. The first impression of the tuner is that it’s worth its weight in gold when it comes to wire antennas. The amplifier is lightweight compared to a tube amplifier, but the ventilation system is louder than I had hoped.

Now it's just a matter of waiting for the ordered Genius 8x2 antenna switch to arrive, and then deciding whether to add a second transceiver—either a FlexRadio 8600/Aurora 520 or to stay with the 6400 for a while and buy a new one when software v4 is available. The goal is to be fully operational in the shack by spring 2026, and to have the antennas renewed by summer 2026. The coming months will be focused on 50 MHz, and then shifting to 80 and 160 meters from autumn onwards.


All installed on a single PC table and easy to disconnect in case of thunderstorm.

DXCC 323 : Prince Edward & Marion Islands

Once again, a rather unexpected last-minute expedition to a rare DXCC. 

And once again, the wrong antennas were in the air. 

This time, ZS8W was active on 10 meters—a piece of cake to work with the Optibeam, if only it hadn’t been lying on the ground while the SteppIR was up in the air. In the end, I still managed to make the contact in FT8. LoTW confirmed and QSL received. 20 DXCC to go.

Then a pleasant surprise: I worked them on 30 meters using the G5RV wire antenna. Although this band isn’t ideally suited for the G5RV, I was able to tune it with the new TunerGenius. To my amazement, he came back to my call immediately. Upon further investigation, it turns out there’s a very interesting radiation pattern on 30 meters, which happened to be perfect for the southern direction. And once again it proves: a seemingly poor antenna works a hundred times better than no antenna at all.

30m pattern on normal G5RV