Pulse Density Modulated HF CW Transmitter/afcw mode\ {Saves Battery Power !} for portable operations

since the TRANSMITTER is not using full duration CW ELEMENTs(using AFCW MODE)(a2) Battery Drain should be less when operating portable via PDM-CW methods

ZAMGATE is the PDM-CW encoder: https://www.zamaudio.com/?p=976

GSTREAMER SCRIPT provides the PDM-CW pulse train:

gst-launch-1.0 -v audiotestsrc wave=ticks tick-interval=10000000 sine-periods-per-tick=1 freq=2000 volume=.9 ! audio/x-raw, channels=1 ! audioconvert ! audio/x-raw, channels=1 ! audioconvert ! queue ! jackaudiosink

TRIGGER-MIDI-MONO is the PDM-CW DE-coder: https://lsp-plug.in/?page=manuals&section=trigger_midi_mono

RECRI KEYER provides the SDR MODULES to FILTER the TRANSMIT PDM-CW pulses before going to the RIG, and provide the midi input CW keyer for TriggerMidiMono AUDIO input TO midi OUTPUT APP https://github.com/recri/keyer

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Comment by Chuck aa0hw on April 27, 2023 at 7:58am

Here is another example of Pulse Density Modulation CW MODE, for a HIGH Q  LARGE FERRITE ROD VLF TRANSMiT ANTENNA:

FERRiTE ANTENNA = TEN 7 inch Ferrite rods stacked together to fill the inside of a 2 inch diam. AiRDUX AiR WOUND COiL https://airdux.com/

coil is parallel resonated by a 1.1uF CAP/coil taps, for max signal output on the VLF band at 8Khz

NOTE: using this T/R device, this setup can be modified easily to perform full QRQ QSK operations https://www.qrpkits.com/eztrswitch.html

FOR PORTABLE OPERATIONs: using PDM-CW MODE, saves battery power, since for each CW ELEMENT, the RF AMP is only operating 1 tenth of the time compared to full duration CW ELEMENTs

PULSE DENSITY TICK STREAM by Gstreamer script: gst-launch-1.0 -v audiotestsrc wave=ticks tick-interval=10000000 sine-periods-per-tick=8 freq=8075 volume=.99 ! audio/x-raw, channels=1, rate=48000 ! audioconvert ! jackkaudiosink

SOUND CARD SDR MODULES used in this demo are from RECRI KEYER:



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