Raspberry Pi 4 - Longwave soundcard SDR CW Transmitter - LIVE demo @ 153Khz, 216Khz & 279Khz

[Chuck aa0hw]

using the dummy sound card JACK set to 800Khz, a Raspberry PI 4 transmitter sends LongWave CW to a laptop receiver over ip using these Gstreamer scripts:

/Pi4 TRANSMITTER:\

qrq@pi4b:~ $

gst-launch-1.0 -v jackaudiosrc ! "audio/x-raw, channels=1" ! audioconvert ! rtpL24pay ! udpsink host=(ip address of Longwave Receiver) port=9999

/LAPTOP RECEIVER:\

qrq@qrq:~$

gst-launch-1.0 -v udpsrc port=9999 ! "application/x-rtp, media=(string)audio, clock-rate=(int)800000, encoding-name=(string)L24, encoding-params=(string)1, channels=(int)1, payload=(int)96" ! rtpjitterbuffer ! rtpL24depay ! audioconvert ! jackaudiosink

Recri Keyer provides the soundcard SDR modules for LO-MIXER, bandpass filters and CW Keyboards https://github.com/recri/keyer

to send audio from the dummy sound card of jack on the RX LAPTOP, to the laptop's 'real' RealTek HD sound card, this Gstreamer script was used: qrq@qrq:~$ gst-launch-1.0 -v jackaudiosrc ! audioconvert ! audiorate ! audioresample quality=0 ! alsasink device=hw:4 sync=false async=false

NOTE: HW:4 = the alsa soundcard number for the laptop's RealTek hd sound card