Audio in (SSB USB)

About

Audio in signal source takes upper sideband demodulated signal from system audio recording device. This option is suitable for analog radio receivers with SSB-USB demodulator connected to PC via audio line in. It's also a good choice for SDR receivers not supported directly by PW-Sat2 Ground Station Software, but supported by third-party applications with upper sideband demodulator.

Usage

1. Choose "Signal source -> Audio in (SSB - USB)" in main window of the PW-Sat2 Ground Station Software and click "Run Source".
2. A pop-up window with settings should appear:

• audio recording device name - in most cases it's sufficient to leave an entry field empty and accept window by clicking "OK". Click for more info about devices.
• audio device sampling rate - most common is 48 kHz, adjust to value supported by your sound card
• SSB-USB frequency offset - the most tricky one - you have to set a center frequency of your TRX radio about 2 - 3 kHz below PW-Sat2 center frequency (435.275 MHz). So if you are going to set your TRX center frequency to 435275 kHz - 3 kHz = 435272 kHz, you have to type in 3000 Hz in this window.

3. After accepting pop-up a new window should appear:

• If proper audio source is chosen you should see similar plot
• Adjust volume to clearly see difference between 'signal' and 'no signal'

4. Run Demodulator

Recording devices

Windows

On Windows basically the best choice is to leave "audio device name" entry field empty. Then, application will use default, system audio input. You can do this in Windows Sound settings.

Linux

To determine device and input name use command:

arecord -L

You can see output like this with your cards and inputs listed:

default
    Playback/recording through the PulseAudio sound server
null
    Discard all samples (playback) or generate zero samples (capture)
pulse
    PulseAudio Sound Server
sysdefault:CARD=I82801AAICH
    Intel 82801AA-ICH, Intel 82801AA-ICH
    Default Audio Device
front:CARD=I82801AAICH,DEV=0
    Intel 82801AA-ICH, Intel 82801AA-ICH
    Front speakers
surround21:CARD=I82801AAICH,DEV=0
    Intel 82801AA-ICH, Intel 82801AA-ICH
    2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=I82801AAICH,DEV=0
    Intel 82801AA-ICH, Intel 82801AA-ICH
    4.0 Surround output to Front and Rear speakers

Choose desired card and type in audio device name, e.g.:

sysdefault:CARD=I82801AAICH

Analog radio

Not-direct SDR support

1. Use software like SDR# suitable for your SDR
2. Configure it for SSB-USB demodulation
3. You may use software like Virtual Audio Cable to direct demodulation software audio output into virtual audio input device