Aviation Headset Interface for Amateur Radios V2.0
I had completed version number two some time ago with the help of a nice aluminum chassis, a Hammond 1590B case that is popular with the Guitar Pedal and the Box Mod enthusiasts. In my case it’s not an amp or a current booster but a passive audio exchange for Aviation Headphones that uses a microphone for amateur radio communications.
The reference for this is right out of the ARRL Handbook 2013 edition, Pages 24.34 and 24.35, schematics by K5ALQ, transformer based and K0IZ, restive-attenuator based circuit that is what I chose for this project.
I am pleased with the level of RF shielding and I am happy with the performance with other headset brands. That was the big payoff. Plus the changes that I made are to R3 resistor where I used a 10K pot that ranges through the resistances needed for different types of microphones. I changed the resistor R5 which was a fixed resistor to a 5K pot that allows some adaptability to just about any aviation microphone going. The switch is an option that will allow for some tweaking for DX by switching in or out C4 Capacitor or R5 5K pot. In this way good adaptability to a bunch of aviation headsets is possible. Fits in the hand well and is easily to use with a keyboard.