After a few failed attempts early last month, a combination of good moon conditions and fine, dry weather towards the end of May/early June helped to complete my first 10GHz EME QSOs. On 22 May I completed my first ever 10GHz EME QSO with OZ1FF -13/-20, followed by ON5TA -12/-15, F6BKB -15/-18 on 23 May, and ON5TA -16/-19, G4YTL -16/-22 on 25 May. 10GHz EME May 2025 Operating position

Over the last couple of weeks, whilst waiting for moon conditions to improve, I took the opportunity to tackle a few issues. Frequency accuracy I use an Icom IC-705 at 432MHz as the IF radio. To measure frequency accuracy I used WSJT-X in freqCal mode and harmonics from a Leo Bodnar GPSDO running at 10MHz fed through a 120dB attenuator. I also used the GB3VHF and GB3UHF beacons which can be copied at my QTH on a rubber duck antenna indoors.

In March I started looking for a 1.2m fibreglass dish as it was evident that the steel dish I was using for 10GHz would not be able to handle the extra weight of the SSPA and power supply mounted at the feed point. After making a few enquiries I found a Prodelin 1132 1.2m offset dish together with a feed arm. I also decided to change the lightweight patio stand used to mount the slew drive and dish for a stronger mount.

It’s been cold and bright for the last few days with good moon conditions so I setup the slew drive and dish outside to test moon tracking with the KN3G controller. The first day was a bit frustrating. It took me a long time to get the dish pointed accurately at the sun and after calibrating azimuth and elevation I kept using the EEPROM Init button instead of the new EEPROM Save button that I had added.

I eventually got round to putting the KN3G controller into a case and have now completed some more bench tests. The controller has been configured with GPS, sun and moon tracking options so that once the Arduino sketch has been loaded it runs as a standalone unit, without the need for a PC or laptop. An unshielded 4 core cable is used for the motors and CAT8 S/FTP for the Hall sensor power and output.

Although it’s been a bit cold working in the garage over the last few days with the temperature close to 0°C, I’ve now completed the metal work for mounting the slew drive on a short stub mast. The mast to bracket base plates I used for the 10GHz setup last year have been adapted for the dual axis slew drive. By installing the slew drive using M10 10mm spacers I have sufficient clearance between the two base plates for a full 360 deg.

The slew drive for the 10GHz offset dish arrived at the start of December and over the last few days I’ve been testing it on the bench with the KN3G controller I started working on in October. The slew drive has two-channel Hall effect encoders built into each motor housing, one for azimuth positioning and one for elevation. Each sensor generates 2 pulses per revolution (ppr) on 2 channels but the KN3G controller just needs to use one channel.

For my first experiments on 10GHz I used a homebrew W1GHZ 10GHz transverter with a 432MHz IF. I recently bought a MKU 10 G5 transverter from Kuhne electronic (now part of Alaris Holdings) and plan to install it at the dish along with the DU3T LNA and Kuhne SSPA. The transverter is small, measuring only 100 x 80 x 14mm, and has two 2.54mm pin headers, a 2 row 4 pin header for power and a 2 row 13 pin header for PTT, monitoring and frequency selection.

I’ve taken part in various EME contests on 2m since 2015 and I’m very pleased to have secured 1st place in the 144MHz Category C Mixed Mode section of the 10th A.R.I. Italian EME Trophy 2024. A big thank you to the organisers and all the stations that took part, it’s always a very enjoyable contest. ARI EME Rules and Results

During the ARRL EME Contest in August and September I was struggling to keep the dish pointed at the moon using manual methods, especially for azimith positioning. I did some research and came to the conclusion that a dual axis slew drive, normally used for solar tracking, was the way to go. These slew drives have been in use for a number of years by radio amateurs across the world to move dishes much larger than 1m offset dish, so a 3 inch model should fine.