Hi Q, tuned, resonant, FERRiTE ROD TRANSMiT VLF ANTENNA for TX'n QRQ CW by a 'key'D square wave

[Chuck aa0hw]

using high Q, tuned, resonant VLF ferrite TX & RX VLF antennas(4.078Khz) a QRQ CW square wave into the resonant, tuned, high Q, TX antenna produces minimal harmonics...and even less of those harmonics survive by the time the same type of RX ferrite rod high Q, tuned, resonant, antenna removes even more of the surviving SQUARE WAVE TX harmonics

this is a QRQ CW example to test how far the TX into a high Q system can be tolerated... 103 wpm at first and then 73 wpm towards the end of the video

TX ANTENNA: it is a large 10 inch by 1 1/4 inch diy FERRiTE ROD(43) MADE FROM 3 layers of FERRITE CABLE COREs inside each other, primary=4 turns, 2ndary = 400 turns with a resonant cap (.1 uF) attached in parallel to 2ndary's output windings

RX ANTENNA: is 2 large air dux coils in series, with 20 ferrite rods(61) stacked inside the air dux coils, setup like a TWIN COIL ferrite rod, similar to C.Crane's TWIN COIL ferrite antenna; a tuning CAP across the two coils resonates at 4.078Khz, the TWIN COIL SETUP uses a stepUP transformer between the two coils, HIGH Z, output of transformer goes to sound card SDR's line input a REAGATE VST plugin performs operations for both the TX and RX

TX: the REAGATE operates as a sidechain gate, only allowing a square wave at 4.078Khz to pass through to the TX antenna according to a CW KEYBOARD keying its sidechain gate

RX: the REAGATE operates a CW REGENERATOR, to convert the 4khz cw pitch to an adjustable CW audio tone output...and to remove any ringing or cw element elongation from the high Q TX/RX antennas

more info on using REGATE for CW-RE-KEYER, cw regeneration at this playlist:

http://www.youtube.com/playlist?list=PLfFan4sDonOdFGeEDASG8tcadafHQ...

https://www.reaper.fm/reaplugs/

https://github.com/recri/keyer