I have now installed SoapyServer on the Pi and I can see that there is a lot of interference as you all mentioned before…
This is with the LNA, 0 Gain, centred on 137 with 2048 BandWidth
This is without the LNA, 49 Gain, centred on 137 with 2048 BandWidth
To me it looks like the LNA is introducing some kind of noise into the circuit or it is severely overloading the SDR receiver…
What do you guys think?
It is difficult to interpret your images, maybe you can try the following:
Run rtl_tcp -a 0.0.0.0 -d 0 on the raspberry Pi
Output (similar to):
rtl_tcp -a 0.0.0.0 -d 0
Found 1 device(s):
0: RTLSDRBlog, Blog V4, SN: 40001150
Using device 0: Generic RTL2832U OEM
Found Rafael Micro R828D tuner
RTL-SDR Blog V4 Detected
Tuned to 100.000000 MHz.
listening...
Then start SDR++, GQRX or similar and connect to a remote rtl_tcp session.
The image shows a 137 MHz center where a RTL-SDR v4 is connected to a Turnstile antenna, no LNA and +/- 4 meters of Aircell 7 coax.
Please share some data including the signal levels.
You have some terrible noise sources, possible candidates:
Switch mode power supplies.
Solar panel installation.
Ethernet switch (never seen it at this level, but who knows)
FM radio broadcast stations.
VHF Pager systems.
Tune over the band and try and find possible sources.
I have brought it down from the attic inside the room and doing some bench tests.
When the LNA is attached to the SDR and a 3 foot RG58 coax is run to the antenna, signal seems OK without any noise (like in the without LNA image above).
When the LNA is attached to the antenna with the same RG58 coax, signal goes haywire (like in the with LNA image above).
Will do some manual observations with SatDump software to see what might be causing this and get some gain values as well.
yeah, satdump_sdr_server is pretty nifty, then running satdump-ui on another computer.
May I ask if you made the turnstile antennae or you bought them?
I am looking to build/buy my own but I don’t have much information at the moment…
