Hallo Ernst,
interesting idea. Would you please give a short description of your equipment and method to make the results comparable.
Thanks
73
Andreas
You only need SDRconsole and a SDR, go to view -> signal history and you can get an the situation as shown, best guess the peak dBm values in both 50Hz CW decoders and subtract them, this morning I got approximately 29 dB, meaning also that there is nothing attenuating the satellite signal (like rain water on the canopy of the antenna feed). Signal history in sdrconsole even has the possibility to download the dBm values in a csv file that you can import in a spreadsheet. I focus on peak values of what I see in SDR console.
You will see that the SNR that you find is mostly unaffected by settings of the SDR, even the bandwidth of the demodulator should not matter too much in my opinion. Important is that you get the maximal signal of the CW beacon for the moment that it is continuous and the real noise floor somewhat but not too far away from the beacon.
Martin DM4IM did this test also I learned during a QSO, he got 34 dB but his antenna is taller than my TDS88 from Triax which I rate at 90cm diameter, his is 150cm, the difference in the antenna gain is like 4 dB (see the 31-May article on my blog), the rest of the differences are due to downconverter or LNB differences or simply the antenna efficiency. I think these are interesting tests to compare. It says in my opinion everything about receiver sensitivity.
I know that SDRplay's rspduo results in realistic dBm values, used a HP stepper attenuation device, a HP power meter and a signal source to calibrate the dBm scale in SDRconsole, it is fine in my opinion.