Minimum Bandwidth of the LimeSDR

Applications
1

Hello,

I am using the LimeSDR as a scanner with GQRX. I need to detect radio waves around 2 GHz that are weak (around - 100 dBm or even less).
That means that the noise floor has to be really low. I can get a noise floor around -110 dBm with the LimeSDR. It would be possible to decrease it even lower if I could reduce the bandwidth.
However GQRX and GnuRadio crash if the bandwidth is lower than 1.4 MHz.

Could somebody give my a clue about that ?

2

I recall something about this but no idea where I read that. Search here and look at gqrx and soapysdr on github issues. Someone here might actually know exactly why but IIRC it’s a bug. But I could misremember and it’s a feature/limitation.

3

Not to be hurtfull … but i remember that the ADC has ~71db of dynamic range coupled with the LNA’s is lots of gain (for me)

4

I think you are talking about this post : LimeSDR minimum RX bandwidth via Soapy and GQRX?

Unfortunately, the person didn’t get an answer…

I could maybe reduce the noise floor with GnuRadio if I insert a bandpass filter before doing the FFT.