I am creating a radio receiver to pick up "walkie talkie" chatter.

success it works fine! I can hear people when they speak on the radio, the only problem i am having is that when no one is speaking the static is insane!

There is very little to no static when someone is talking but there is more than my ears can bear.

So my question: How can I filter out the interference when the radio is "idle" from the image its clear to see I have a very high center frequency (which is just silence and constant)

and then I have some "static" between -70 and -80 db, when there is radio chatter the db jump above -60, so I am guessing I need to filter out everything lower?

I am very new to this any guidance on how and what to do would be appreciated.

enter image description here


Since you tagged your question with GNU Radio, I am assuming that is your SDR software package.

If you look under level controllers, you will find a function block called "Power Squelch". This function:

Sets the threshold (in dB) where the squelch control switches between MUTED and UNMUTED states. If Ramp is enabled, there in an ATTACK state between MUTED and UNMUTED and a DECAY state between UNMUTED and MUTED.

This is the functional equivalent of the squelch control on an FM communications receiver although in GNU Radio, it is not restricted to FM. It will act as an audio gate or switch that mutes the audio until a signal above the threshold is received.

  • $\begingroup$ yup forgot to mention I am using a hackRF and thank you for this answer $\endgroup$ – TheHidden Jan 25 '18 at 14:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.