Rx Amplitude do not show the real values
Posted: Sat Apr 10, 2021 3:17 pm
Hello Community,
I am still on the way to switch from SDR Uno to SDR console because of connecting my FT 817 to sdr console.
In order to see how sdrc works I made a simple setup.
1. Rspdx on sdr uno
Signal generator set to -40,2dBm, cable and connectors compensated to -40dBm real input power on rspdx. Frequency set to cw 435MHz, connected to port b of rspdx. Rspdx set to am modulation. Test was performed with bw of 500khz and 2mhz.
Test with different gain and bw settings. Read out amplitude between -39.1 and -40.7dBm =>everything fine.
2. Start with Sdr-console and bw of 2mhz and 500Khz. Measured the same signal with different gain and if gain settings. Readout amplitude between -59 and -22dBm, always depending on the gain values.
=> no change to get the real input power of a unknown signal.
Now the questions. Did I used a wrong setting in sdrc?
If not, how can I perform with rspdx and sdrc a useful measurement of the real input signal power level?
Or how can I calculate the real input power depending on the different gain settings in sdr-console settings?
The only positive thing is that the relative change of input power is shown in the right way. This mean a change of 10db of input power level is shown as a change of 10 db in the sdrc display.
Any good ideas?
I am still on the way to switch from SDR Uno to SDR console because of connecting my FT 817 to sdr console.
In order to see how sdrc works I made a simple setup.
1. Rspdx on sdr uno
Signal generator set to -40,2dBm, cable and connectors compensated to -40dBm real input power on rspdx. Frequency set to cw 435MHz, connected to port b of rspdx. Rspdx set to am modulation. Test was performed with bw of 500khz and 2mhz.
Test with different gain and bw settings. Read out amplitude between -39.1 and -40.7dBm =>everything fine.
2. Start with Sdr-console and bw of 2mhz and 500Khz. Measured the same signal with different gain and if gain settings. Readout amplitude between -59 and -22dBm, always depending on the gain values.
=> no change to get the real input power of a unknown signal.
Now the questions. Did I used a wrong setting in sdrc?
If not, how can I perform with rspdx and sdrc a useful measurement of the real input signal power level?
Or how can I calculate the real input power depending on the different gain settings in sdr-console settings?
The only positive thing is that the relative change of input power is shown in the right way. This mean a change of 10db of input power level is shown as a change of 10 db in the sdrc display.
Any good ideas?