I’m following a guide for the Raspberry Pi SSTV Decoder(here https://github.com/davidhoness/sstv_decoder/blob/master/README.md)

and I’ve run into a couple of issues. 

Everything works fine up until

rtl_fm -M wbfm -f 98.8M | play -r 32k -t raw -e s -b 16 -c 1 -V1 -

I get audio but with a high pitch whistle and blips in the audio. I tried an alternative command as follows

rtl_fm -f 98.8M -s 192000 -r 48000 - | aplay -r 48k -f S16_LE -t raw -c 1

This seems to get rid of the high pitch whistle but I still get blips in the audio. Using the original command I progressed to QSSTV. Going via “internet” as suggested brought up what looks like an older version of QSSTV with different options to what is shown in the guide. I manually downloaded and installed the latest version which does match the guide. However when I load and configure it I get an error

“PulseAudio read init error Connection refused”

I read somewhere that this could be because the PulseAudio server isn’t running, so I manually started the process with “pulseaudio –start” loaded QSSTV, configutred it as per guide and it was happy, great.

So now the process is:

Boot Pi

Start Pulseaudio server

Start RTL_FM

Confirm audio is good


Now when I load QSSTV the audio which was good(ish) becomes extremely garbled. Closing QSSTV restores the audio to normal.

I’m at a loss now as to what is wrong,

RTL_FM works (sort of) with or without pulseaudio server running.

QSSTV will not work without pulseaudio server running.

RTL_FM will not work with pulseaudio server running at the same time as QSSTV

Presumably there is some sort of conflict somewhere. I’m new to the Raspberry Pi and it’s very frustrating trying to make it do anything useful. I’d really like to try and get it working though as an SSTV receiver for the ISS