High Voltage protection/insulation/isolation between RIG/CW KEYER & a PC sound card input by Pyrex Glass & induction coils

[Chuck aa0hw]

testing using 2 ferrite bobbin core inductor coils inside thick pyrex glass measuring cups to provide high voltage isolation protection between a RIG/cw keyer and a PC soundcard's input

used for sending CW AUDIO over SonoBus by keying a TWIN-T oscillator

the output of the TWIN-T goes to a class D amp and the output of the class D amp goes to the 1st ferrite bobbin core inductor(1.8mH) that sits inside a Pyrex Glass measuring cup

the input of the PC sound card connects to a 2nd ferrite bobbin core inductor coil(1.8mH) that also sits inside a 2nd Pyrex Glass Measuring cup and the two Pyrex measuring cups are brought together to provide enough inductive coupling for the SonoBus input FX PARAMETRIC EQ plugin to amp/filter the twin-t's keyed sidetone(which is low in volume and has unwanted harmonics) and send it over ip to the other OPs listening on your SonoBus Room.. and also to your own headphones/speakers for monitoring your own post FILTERED/amp'D CW sidetone in real time, @near zero latency

sonobus

https://sonobus.net/

[Chuck aa0hw]

this shows the twin-t oscillator setup to use a TRACKING CW AUDIO BANDPASS FILTER...so you can vary the pitch of the SDR LO-MIXER module, and the BP filter's 'center' will track along with the cw pitch automatically as well as the bandpass filter bandwidth and "Q"

the frequency of the TWIN-T oscillator is set to  @700 Hertz  ...instead of VARYING the TWIN-T and then having to vary the bandpass filter too.... Recri Keyer SDR modules are used to first capture the TWIN-T's sidetone at the MIC INPUT jack of this laptop, and then output a dual i/Q channel, by using Recri Keyer's HILBERT CELL...the hilbert cell connects to the input of an i/Q bandpass filter module...then to an i/Q Gain Module...then finally to the i/Q LO-MIXER moduel, where you can move the GUI dial on the LO-MIXER gui... and get any CW PITCH you want... and the center freq of the CW AUDIO bandpass filter just TRACKS along with the CW pitch chosen on the LO-MIXER GUI dial.... so no matter what freq you choose with the LO-MIXER, the center of the bandpass filter tracks along with the CW PITCH selected... and the bandpass width and "Q" remain the same too... https://github.com/recri/keyer