A strange phenomenon occurs on my LIMESDR. FM signals can be received at the HF frequency. For example, a 90M FM radio can be received at 3M frequency. Is this a hardware problem? My LIME version is 1.4S.
No, this is to be expected with an SDR and strong signals, due to aliasing. If it causing you problems you can reduce/remove this with filtering. There are vendors that sell e.g. “band stop” filters for broadcast radio and TV bands, which are the most common source of problems.
Thank you very much
Bandpass filtering will help in all regions that you recieve in. It filters out frequencies higher & lower than the ones you are interested in.