RTL_FM and CTCSS/DCS?

[doabbs]

Hi,
I have a fully functional Raspberry PI 3 working with my RTL SDR USB device and have to say it's pretty nice to have such a light weight option for streaming audio. The one major issue I can't overcome has to do with CTCSS tones. I have not been able to find any way to filter out transmissions that aren't on the CTCSS tone needed and because of this the super awesome setup I have is pretty useless. Without CTCSS filtering there is no way to listen to my feed since there are too many other folks on the same frequencies using different tones or no tones at all.

I've searched high and low and have been unable to find any way to accomplish this. Hoping that someone here has run into this or is aware of any other possible solutions? I'd hate to have to start from scratch but as of right now the only other options I see are:

Abandon the SDR dongle and just leverage a scanner and use a Line In USB dongle for the pi
Leverage another operating system like Windows on an Intel Stick and use something like SDR#
Learn how to implement CTCSS tones into RTL_FM myself and create my own fork (with all the free time and coding experience I don't have)

 

[cmdrwill]

Build a HiPass filter into the audio stage in the Pi.

 

[marklt1]

I have the same needs as you. Using Darkice or some other means of filtering the tone is a simple as adding a highpass filter for 250Hz into a configuration file. We want to discriminate a certain tone (mine is PL 131.8 Hz) for squelching the calls. RTL_FM doesn't do a very good job on its squelching of weaker signals.
I too don't have the time or extensive Linux programming skills to develop one, thus my search has landed me on this page. I have some ideas how it can be done by piping in the audio into an audio utility that can pass though if that the certain tone frequency is detected.
Hopefully someone can come up with something.

Hi,
I have a fully functional Raspberry PI 3 working with my RTL SDR USB device and have to say it's pretty nice to have such a light weight option for streaming audio. The one major issue I can't overcome has to do with CTCSS tones. I have not been able to find any way to filter out transmissions that aren't on the CTCSS tone needed and because of this the super awesome setup I have is pretty useless. Without CTCSS filtering there is no way to listen to my feed since there are too many other folks on the same frequencies using different tones or no tones at all.

I've searched high and low and have been unable to find any way to accomplish this. Hoping that someone here has run into this or is aware of any other possible solutions? I'd hate to have to start from scratch but as of right now the only other options I see are:

Abandon the SDR dongle and just leverage a scanner and use a Line In USB dongle for the pi
Leverage another operating system like Windows on an Intel Stick and use something like SDR#
Learn how to implement CTCSS tones into RTL_FM myself and create my own fork (with all the free time and coding experience I don't have)