Limesdr mini seems to receive fm everywhere

Projects LimeSDR
1

whether it be 60-70 mhz or 140-150 mhz, my limesdr mini receieves fm in strange ranges(using sdrangel). i don’t really know if something is wrong with the board or not, i’ve had strange issues with it, but most of seems to be due to poor software(nonfunctional waterfall in gnu radio, sdrangel output appears to “jitter”). however, this is a bigger issue, and i can’t seemingly tune in anything else.

on top of that, when i attached the ham-it-up, i proceeded to be unable to receive anything but fm, with it covering every band, being able to tune in fm at anywhere from 0 hz to 3 ghz.

anyone have any clue what’s going on? thank you!

2

You need bandpass filtering.

Ed

1 Like
3

To be more specific: Broadcast FM signals are ridiculously strong compared to many of the other types of signal you may want to work with. Devices like the Lime don’t have the best image rejection, so if you want to look at (IF + deltaF), and there is a strong broadcast FM signal at (IF - deltaF), you are going to get that FM signal. Ideally, you need both a bandpass filter around the frequency range of interest and a notch filter for the FM broadcast band.