Frequency range not locked to source limitations

[helioshk]

When connecting to a spyserver, the signal frequencies are 6250 Hz too low, in the FFT as well as the audio, compared to other spyserver client (sdr#) and calibrated reference.

6250 Hz would be half the NFM bandwidth, but I don't know where that is coming from.

When connecting with sdrpp to a local Airspy, the frequency is accurate.

[helioshk]

I think the problem is, that the frequency range can be changed in SDR++, even if spyserver doesn't allow changing the frequency:

# Allow clients to retune and change of gain of the device
#
allow_control = 0

[AlexandreRouma]

Not a bug, SDR++ just doesn't support locking the frequency range.