Bulgarian 10 GHz
Beacon Project

Following our successful 10 GHz activation from LZ9X during the IARU contest in October 2025, we decided to build and install Bulgaria’s first-ever beacon on this frequency.

My Bulgarian friends Rumen, LZ1JH; Krasi, LZ1KQ; and George, LZ1GHT, obtained the necessary permits and organized transportation, site access, and installation logistics. My job was to build and test the beacon in Canada, then bring it with me to Bulgaria.

The beacon was a replica of the VE7SAR beacon we installed three years ago. It uses a W1GHZ ×9 multiplier PCB, a new-style local oscillator from VA3TO, and new beacon software. I also added a 10 GHz band-pass filter (BPF) to eliminate unwanted harmonics.

The power amplifier is a JCA unit delivering approximately 180 mW to an omnidirectional 2×10 slot antenna built by PE1RKI.

Construction went smoothly, with no major surprises. Writing the new software took some time, as it needed to allow a single Arduino controller to operate both the local oscillator and the CW beacon message. After completing the tests, I added the appropriate attenuators to set the output power to 180 mW. Although the JCA amplifier can produce approximately 250 mW, we decided to operate it conservatively.

In May 2026, I travelled to Bulgaria. With all the necessary permits in place, we scheduled our trip to the installation site at Vrah Botev for June 10, 2026.

The site, in grid square KN22LR, sits approximately 7,940 ft (2,420 m) above sea level and is in a restricted area. With the station chief’s help and guidance, we began our journey up the mountain. Reaching the site required a 4×4 vehicle and approximately 2.5 hours of driving over very rugged terrain.

On arrival, Krasi, LZ1KQ, and I began the installation. We mounted the beacon in the top corner of the main room at the top of the building, next to the TV tower.

To test the beacon, we had arranged for our Romanian friends Marian, YO7BM, and Miki, YO7CW, to travel closer to the border and set up their 10 GHz systems. Their testing location was 202 km from our site.

As soon as we switched on the beacon, they reported a 599+ signal. A great success!

We then set up our own 10 GHz and 24 GHz systems outside the building. First, we made a 10 GHz QSO and thanked our Romanian friends for helping us test the beacon. We also attempted a 24 GHz QSO and were able to copy their signals, but the weather soon changed and we had to head back.

The return journey involved another 2.5 hours of driving down the mountain slopes. Our mission was accomplished, and we were all delighted!

The LZ0SHF/B beacon was now on the air on 10.368820 GHz.

I would like to thank the members of the Surrey Club for their generous donation of the 2×10 slot antenna. Special thanks also go to John, VA7XB, for his generous cash donation, and to Scott for donating the power sensor for the HP 432A meter.

Your donations were greatly appreciated. The Bulgarian Federation of Radio Amateurs (BFRA) also sent us a thank-you letter for putting Bulgaria’s first 10 GHz beacon on the air.

The beacon has already encouraged several Bulgarian amateurs to build their own 10 GHz systems. We expect at least four LZ stations to be active on 10 GHz during the next IARU contest in October 2026.

But there was another exciting surprise.  After installing LZ0SHF/B, we received a video from YO8TK in Romania, approximately 540 km away, showing reception of the beacon!  That is an amazing result for a beacon transmitting just 180 mW.

I am extremely grateful to everyone who helped make this project a reality: those who assisted with the electronics and construction, those who arranged the permits and difficult mountain access, and especially everyone who contributed equipment and donations.

This project shows once again what amateur radio operators can achieve when they work together across borders.  Thank you all for your support!

There will be more to come.The beacon has already encouraged several Bulgarian amateurs to build their own 10 GHz systems, and we expect at least four LZ stations to be active on 10 GHz during the next IARU contest in October 2026. There was also an exciting surprise after the installation: YO8TK in Romania sent us a video showing reception of LZ0SHF/B from approximately 540 km away—an amazing result for a beacon transmitting just 180 mW.

I am extremely grateful to everyone who helped make this project a reality, from those who assisted with the electronics and construction to those who arranged the permits and difficult mountain access. Special thanks go to everyone who supported the project with equipment and donations.

This project shows once again what amateur radio operators can achieve when they work together across borders. Thank you all for your support, and stay tuned—there will be more to come!

73,
Dino VE7NX