10 GHz optimisation

The dish used for the 10GHz EME tests during the ARRL contest has been moved to the back garden where I have visibility of the moon from 80 deg. to 235 deg. azimuth when it’s at 25 - 30 deg. elevation or more. At the moment the centre of the dish is only 1.4m off the ground so I’ll gain a bit more moon visibility when I move it higher.

The initial sun noise tests were good but I was over 1.5dB down compared to VK3UM EMECalc. I also wanted to find a more reliable method of pointing the dish, especially the azimuth adjustment, so I connected up a Yocto 3D sensor that I had used for initial alignment of the 2m EME array. After running several sun noise tests and comparing the Yocto positional information with the expected sun position indicated by SunCalc I now have a lookup table for azimuth and elevation. The Yocto 3D elevation readings are within 0.5 degree of the sun noise peak but so far I’ve found the azimuth readings unreliable and need to conduct some further tests. I also have a small digital inclinometer and this appears to be slightly more accurate than the Yocto 3D device for elevation readings.

I made some minor adjustments to optimise the feedhorn position and the sun noise measurement is now much closer to VK3UM EMECalc. I also took some ground to cold sky measurements and these are also close to the EMECalc prediction.

SFU @ 10 GHz = 378

References

• SunCalc.
• Yocto-3D-V2 USB Position Sensor.