Entire FM Band Recording/Replaying

#1

Hi,

I’m looking for an SDR for a specific task… I want to record the entire FM Band (87.5mhz - 108mhz ~20.5mhz)
and be able to replay it.

I know, an sdr will not be able to replay the signal with a realistic dynamic range, however that is not the task for me.

Any Idea, if a lime mini would be able to do this (stability, without samples beeing lost)?

#2

I suspect that the real problem for your idea would be disk storage capacity:
20.5 MHz sampled at 20.5 MSPS 12-bits IQ would require 61.5 MB/second (or ~ 5.4 TB every day).

#3

We wrote software to do exactly that in my product. It’s actually requiring ~95MB/s write speed as you need more than the 20Mhz to catch the stuff that falls slightly out of band. 14TB drives roughly yield about 5 days worth of RF recording. And since it’s recorded in ADPCM WAV format, there is no 12 bit file, just 16, so there’s blank data in there as well to maintain compatibility. The other problem is that you’d have to write playback software as well that can handle that size and type of file. Nothing off the shelf can do it today.

And no, the mini has stability issues that Lime seems to ignore or won’t give a proper response as to why it drops samples at it’s max bitrate requested. You have to use the big one to do this.