×

Message

EU e-Privacy Directive

This website uses cookies to manage authentication, navigation, and other functions. By using our website, you agree that we can place these types of cookies on your device.

View e-Privacy Directive Documents

You have declined cookies. This decision can be reversed.

Posts from category "Hamradio"

A simple SDR QO-100 Ground Station (Part 4: GNU Radio Flowgraph)

GitHub repository

TODO

Audio streaming scripts

TODO

Flowgraph startup

TODO

LNB Correction

TODO

Practical use

TODO

Limitations

TODO

A simple SDR QO-100 Ground Station (Part 3: Software Setup)

SDR Box Software Diagram

Virtual audio devices setup

Although it is possible to stream audio from/to Raspberry Pi's audio port, I wanted to separate the QO-100 audio from all the other "normal" audio in order to avoid inadvertently transmitting system system notifications or such like. 

Nowadays, for every popular OS there is a "virtual sound card" kind of software (such as Virtual Audio Cable for Windows or Loopback on macOS).

For Linux, no additional software is required (other than PulseAudio, which in Raspberry Pi OS comes installed as a default) and this is a simple matter of loading the right modules in PulseAudio.

Add the following to your /etc/pulse/default.pa:

load-module module-null-sink sink_name=qo-100-tx
load-module module-null-sink sink_name=qo-100-rx

And restart pulseaudio:

$ sudo killall pulseaudio

Because GNU Radio supports only ALSA devices, you will also need to create the ~/.asoundrc file with the following content:

pcm.qo-100-rx {
    type pulse
    device qo-100-rx
}

ctl.qo-100-rx {
    type pulse
    device qo-100-rx
}

pcm.qo-100-tx-monitor {
    type pulse
    device qo-100-tx.monitor
}

ctl.qo-100-tx-monitor {
    type pulse
    device qo-100-tx.monitor
}

Audio streaming

TODO

CPU overclocking

TODO

Disable WiFi

TODO

GNU Radio installation

TODO

 

Continue reading in Part 4 >>