RTL-SDR poor sensitivity


#1

Today I did some sensitivity measurements comparing the SDRplay with various rtl-sdr receivers.

I was motivated to do this because I can get an almost perfect weather map from the NOAA satellites with my SDRplay, SDRuno & WxtoImg combo with my antennas but what I see via SatNOGS observations is very poor partial picture.

These tests were done without external LNA and without fancy test-equipment, just careful observations of the spectrum display. The SDRplay shows actual dbm results.

What I found is the noise floor is 30dbm better on the SDRplay. Signal to noise ratio 5dbm better on the SDRplay.

I have been experimenting with the gain settings via satnogs but they don’t seem to make much difference. Looking at other Observations from other Ground Stations I see very few which are much better than my omnidirectional stations with LNA4ALL preamps.

So the questions are, how can I improve sensitivity as there is little benefit in leaving stations running with mediocre results.
Is anybody working on the ability of using better SDRs than rtl-sdrs? I believe the SDRplay will run on Linux with Cubic SDR. Not a user-friendly GUI but it works on Linux.

I’m very happy with SDRpl;ay/SDRuno but I hate having to use Windows, it’s such a proverbial pain… once you get used to Linux.


#2

I am not sure whether it is possible to directly compare noise and SNR from a SatNOGS waterfall and SDRplay. They may be calculated differently. Nevertheless, the fact that SDRplay received APT is decoded better, is an indication that something in SatNOGS receive and/or decode chain is not fully optimized.


#3

There are several stations already that use Airspys and Ettus USRP devices with good results.

I don’t know how much has been said before publicly, but there are plans for replacing the present SDR device interface in SatNOGS for better integration with more devices. I don’t know when it will happen because we are all very busy at the moment.


#4

I was only comparing NOAA APT weather-map reception quality with or without SatNOGS by the quality (visual) of the received picture. Same SDR. No measurements. The comparison between rtl-sdr and SDRplay was done without SatNOGS.


#5

Thanks, I shall be watching progress closely.


#6

I have a SDRplay RSP1 waiting for it…I’m not happy with rtl-sdr