Chuck aa0hw's Blog – May 2020 Archive (6)

zitaNJbridge provides the near zero latency audio over ip link between the RIG/pi4 interface and the remote OP's desktop https://kokkinizita.linuxaudio.org/linuxaudio/

recri keyer's CW Keyer APPs used from :…

this is a follow video to this one in this series:

https://youtu.be/YCJpS0kCbQ0the PC's native MOBO sound card was set to 192Khz to enable direct 88Khz CW TRANSMIT from the AD5DZ CW KEYBOARD sending a text file

the LF RF 88Khz output of the PC's sound card goes to the input of the LOXJIE A10…

brief experiment to see if by using the maximum sample rate of a sound card, 192Khz, would allow sending QRQ CW at 96 Khz(the highest frequency possible at 192Khz sample rate) at 96 wpm

Gstreamer scripts are used by the TRANSMITTER and RECEIVER

- TCP CW LF RF over IP -

TRANSMITTER:

****************

gst-launch-1.0 -v…

1. send AFCW MODE

2. use this GSTREAMER BANDPASS FILTER between your CW KEYER's audio output and the RIG's LINE INPUT

**********************************************************************

gst-launch-1.0 jackaudiosrc ! queue ! audioconvert ! audiowsincband mode=band-pass lower-frequency=600 upper-frequency=800 length=700…

VLF BAND TEST on 10101 Hz

20 watt VLF AMP to compact DELTA LOOP ANTENNA

received by a Ferrite rod RX VLF antenna connected directly to this recording laptop's MIC INPUT jack, demodulated from VLF into CW AUDIO by the AD5DZ SDR APPs: LO-MIXER & FILTER modules

CW TRANSMIT VLF RF Gstreamer BANDPASS FILTER script…

using all AD5DZ SDR software MODULES to capture & demodulate a QRQ CW signal heard on the VLF BAND at 10101 Hz...this video also shows one special adjustment made to a RECRI KEYER FILTER file setting to create a custom CW AUDIO BANDPASS FILTER for QRQ CW RX copy

a VLF RX ANTENNA - tuned bi-coil ferrite rod - brings in the VLF SIGNAL…