Hello JM, Both methods should give the relative NF of the different dongles. That means that the difference between the tables should be a constant. This is what you have found:
Diff FM to AM > E4k FC0013 R820T > 137 MHz 4 4 5 > 434 MHz 5 5 7 > 1090 MHz 5 4 4 > 1500 MHz 6 4 8 The table is the difference between two measurements so uncertainties add. It seems the correct value is 4 to 5 dB and that there is a small error at 1500 MHz for the R820T. Regards Leif > Here is an update of this morning's measurements, mostly consistent except > for a couple of values > for which I must have forgotten to set the RF gain when launching the > GNURadio application, > and the addition of the measurements at 1090 MHz > > FM modulation: synthesizer output power in order to reach 10 dB SNR (3 kHz > modulation, > 5 kHz deviation). All values in dBm > E4k FC0013 R820T > 137 MHz -105 -112 -112 > 434 MHz -105 -111 -112 > 1090 MHz -96 -76 -109 > 1500 MHz -95 -58 -102 <- major correction ! > > AM modulation: synthesizer output power in order to reach 10 dB SNR (3 kHz > modulation, > 30%). All values in dBm > E4k FC0013 R820T > 137 MHz -109 -116 -117 > 434 MHz -110 -115 -119 > 1090 MHz -101 -80 -113 > 1500 MHz -101 -62 -110 <- major correction ! > > JM > >
