Submarine 82hz ELF soundcard SDR, QRQ CW, QRP, Transmitter & Receiver - test run at 82 wpm

[Chuck aa0hw]

TRANSMITTER SETUP:

CW KEYBOARD sends 82 hertz CW out one of the sound card's line output jacks to a class D 30 watt audio amp... the audio amp output is connected to a FERRITE BOBBIN CORE INDUCTOR COIL (@ 1.8mH) - the output of the 30W audio amp 1st goes to a POWER TOROID TRANSFORMER with multiple windings and tested to see which set of windings provides the best impedance match between the amp output and the 1.8mH ferrrite bobbin core inductor coil Transmit antenna

RECEIVER SETUP:

a large FERRITE ROD LOOPSTICK ANTENNA is connected to the recording laptop's MIC INPUT jack...picking up the ELF Transmitter's signal... it either routes to the speakers directly through a 20db software amplifier...

OR

goes to the input of a CW REGENERATOR - which uses ZAMGATE(in sidechain mode) and a sinewave generator - ZAMGATE puts a rise/fall time onto each output pure sine wave cw note from the sine wave generator held back at zamgate's top port...the sidechain port is "keyed" by the 82hz signal and allows the sine wave to go through the zamgate top port, and the original cw note is replicated exactly at its output into a pure sinewave shaped cw output according to the sine wave generator frequency and the rise/fall /threshold settings on zamgate