tweaking RTL_FM on a Ras-Pi. Squelch is either all or nothing

[theconqueror]

I've been trying to tweak this for awhile now and I dont know what else to do here. With the command below the squelch stays open. I can hear the audio when transmissions come across and they sound decent. If I increase the squelch to 54 nothing comes through. What do I need to tweak here?

/usr/local/bin/rtl_fm -d 0 -M fm -f 460.550M -p 0 -l 53 -g 48.0 -t 2 -E pad -s 12k -| /usr/bin/lame -r -s 12 --resample 22.05 -m m -b 16 --cbr --lowpass 4 - - | /usr/bin/ezstream -c /etc/ezstream_bcfy.xml > /var/log/bcfy2.log 2>&1 &

 

[thewraith2008]

Probably nothing, but what about the option '-t 2'. Isn't that an option only for scanning? (default is 20)

What source are you building this from?
I don't think it's from 'osmocom' because you have an option '-E pad' for outputting silence when squelch is closed, that is not part of that code.
I know for windows, without that silence padding, rtl_fm becomes unresponsive until squelch is opened.
Could be something amiss with the code in how it adds padding?

 

[DRL-XM43]

gain looks aggressive I think 49 is full gain. I find a lower gain like around 36 and a lower squelch like 42 works for me, assumes you have a decent signal.

 

[theconqueror]

I had increased the gain because it seemed to help with this nasty background hum that I'm getting. I dropped the gain down to 42 and I just heard some audio on the stream, but that background hum is still there.

I ditched the "-t 2", good catch. The source is here https://github.com/keenerd/rtl-sdr I'm just following the radio reference raspberry pit RTL_SDR build Raspberry Pi RTL-SDR Broadcastify - The RadioReference Wiki

 

[theconqueror]

Ok, with the gain at 42 I heard some audio and the squelch was working, but now no audio is coming across the stream again. I noticed when i was killing all of the processes I got an error saying that lame wasn't running. Grrr, this is just frustrating to see everyone else getting this running but I keep running into problems

 

[DRL-XM43]

I use SOX (play) on my Linux Mint 19.3 I do not know if the combo can work on your setup - but here is a sample of my config - it works great for me on any number of analog or digital frequencies (I pipe digital to DSD+ running under wine) but anyway this is what it is....

rtl_fm -d 1 -M fm -F 0 -p 0 -s 12000 -E dc -E deemph -g 37 -l 42 -f 141.390M -f 142.050M -f 142.290M -f 142.335M -f 142.425M -f 142.830M | play -r 12000 -t .raw -e signed-integer -v 5 -b 16 -c 1 -V1 - -d

 

[theconqueror]

I can use sox if I just want to listen to it, but in this case I want to stream it to broadcastify