I started strf around 400.5 MHz centered, on rtl-sdr V3, attached to vertical 6 el yagi,no filter, no preamp. Tested setup first with SDRPP.
I have this telemetry carrier from Hook of Holland (7 km distance) on 401.1 MHz which I use fo gain settings test.
Clearly over 40 dB C/N and the waterfall shows passing satellites too.
This is with gain setting 34 dB, with 39 dB the C/N does not change much but the base noise level does.
However, running strf with the same gain settings shows this for 401.1 MHz
That’s a very weak signal. I would not have checked this if I had seen satellites in my strf but as you can expect I did not see any satellites in strf with these gain settings either.
running this:
./rtl_capture.sh 400.3e6 24h 39
where $1 is the frequency, $2 is the duration and $3 is the gain
which outputs
Filename: /media/hacker/4e020de5-0ada-4815-9e3a-7d4889be1ea4/satobs//fifo
Frequency: 400.300000 MHz
Bandwidth: 2.048000 MHz
Sampling time: 0.488281 us
Number of channels: 40960
Channel size: 50.000000 Hz
Integration time: 1.000000 s
Number of averaged spectra: 50
Number of subints per file: 60
Starting index: 0
Found 1 device(s):
0: Realtek, RTL2838UHIDIR, SN: 00000001
Using device 0: Generic RTL2832U OEM
Found Rafael Micro R820T/2 tuner
Sampling at 2048000 S/s.
WARNING: Failed to set bandwidth.
Tuned to 400.300000 MHz.
Tuner gain set to 38.60 dB.
Reading samples in async mode…
Allocating 15 zero-copy buffers
In which I can not see a problem.
Any clue what’ s wrong here ?
Edit: Switched to Airspy Mini with same antenna setup, checked after few minutes and see:
