A few weeks before the first weekend of the 2.3 GHz and Up ARRL EME Contest I moved the 1.2 m offset dish I use for 10 GHz EME back to the rear garden. I had spent some time evaluating both positions and came to the conclusion that having more moon time towards the east would be better. With the dish in the new position I took some sun noise measurements to calibrate the slew drive and then completed a sky survey.

I finished building and testing the 10 GHz 25 W GaN PA at the end of February and installed it at the dish on 2 March. My first QSO was with ON5TA -16/-17, followed by OZ1LPR -2/-16, GW3KTH -19/-22 and IW2FZR -16/-18. 10 GHz feedtray March 2026 20 - 23 March Between 20 and 23 March I added 13 new initials, including the T7/IW2BNA DXpedition to San Marino on 22 March.

Good results had previously been achieved on 10 GHz EME using 10–12 W into a 1.2 m dish. Over the winter period, the decision was made to increase transmit power to approximately 25 W by constructing a higher-power amplifier stage. With no prior experience in building RF power amplifiers at microwave frequencies, a substantial amount of time was spent reviewing published designs, conference proceedings, application notes and device data sheets.

I haven’t been active on 10GHz since the end of August, when I moved the dish to the front garden where I have more moon visibility to the west. During October and November I moved the transverter and SMPS for the PA from the feedtray into a separate unit which is located under the the feedarm, close to the dish. I also made up some new feedarm supports for the dish as the previous ones were a bit short.

During the ARRL EME contest I completed 15 QSO’s on 10GHz, including 6 initials. I was very pleased to work ON4CDU, my first 1.2m dish QSO. Being able to peak the dish on moon noise using the new nudge switches was extremely useful and I consistently saw 0.5 - 0.7dB of moon noise. 16 Aug 2025: OZ1FF -13/-19, F2CT -15/-15, OK1DFC -12/-19, ON5TA -13/-19, OZ1LPR -3/-19, DL4DTU -11/-15, OH3LWP -11/-19, ON4CDU -18/-22

KN3G controller The combination of the KN3G controller and slew drive have been working well but occasionally I need to peak the dish on sun or moon noise. When I built the controller I didn’t use any manual switches - all of the main functions I need are available through the Nextion touch display. I’ve now added two SPDT biased switches to the front panel. They’re wired directly to the motor controllers and by uncommenting a line in rotator_features.

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.