[Moon] Adding 432 MHz antennas parameters to VK3UM EME calc

Conrad PA5Y g0ruz at g0ruz.com
Tue Sep 21 09:27:59 CEST 2021


Hello all.

I am trying to use VK3UM's EME calc to get some idea of predicted performance on Sun noise on my very new 432MHz array. My antennas are not in the VE7BQH list, the nearest thing to them are LFA 23eles, gain and 3dB BW are very similar. Of course I would like to know how to update the antenna parameters, I can get all the necessary data to do so but I cannot see how to edit the table from the GUI. Or even how to properly add a custom antenna array.

Peter G3LTF has done a good job of dealing with these measurements for dishes on 23cms and above but not yagis on 432MHz.

After updating the Solar Flux and using VK3UM noise sources to find Leo I seem to be 1.5dB down on Sun noise. I have 2 methods of measuring noise, 1 is to use an audio millivoltmeter and step attenuator the other is to use a Perseus RX on the 28MHz IF of my transverter. I use a wide bandwidth and long averaging in the 'S' meter which is essentially the same as the beloved continuum mode but without any potential errors from sample rate conversion that would be otherwise necessary.

I have taken a great deal of care to minimise losses;  only 1.3m of SCF12-50 from the DE to the splitter and then 10cm of RG393 to my relay. The measured losses are less than 0.1dB to preamp. The preamp is an SAV451+, I should see 12.0 dB sun noise at current levels and I see 10.5dB. The correlation between the audio millivolt meter and Linrad/Perseus is excellent.

So I don't understand the problem and would appreciate any pointers.

73

Conrad PA5Y



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