|[AMRadio] Ultrasonic feedback|
k5pgw at yahoo.com
Mon Feb 2 21:56:47 EST 2009
Can anyone direct me to a source of information or a tutorial on Ultrasonic feedback in modulator circuits such as that in the Heathkit Apache.
My Apache modulator squeals when the microphone gain is raised and the modulator tubes draw a lot of current. As long as the microphone gain is kept very LOW the current does not take off and there is no squeal coming from the modulator section. I am going to go through the section with a screwdriver and a nut driver to tighten up the grounds to the chassis and tube socket.
Ultrasonic feedback is a NEW phenomenon to me. Someone mentioned ferrite beads some time back. Thanks for reading. 73, John, K5PGW
More information about the AMRadio mailing list
This page last updated 16 Dec 2017.