On Fri, 10 Jun 2005 04:04:32 GMT, "The Tube Man"
wrote:


On many of the older tube type base radios, there is a capacitor (like a
4uf) on each the pins of the mic connector...like on a 4 pin mic male
connector there might be 4 each caps, wired in series, with a leg of the
cap wired to one of the pins with one leg of the caps going to ground.

Question is:
1-why is this done

To prevent 60/120 cycle noise from entering the radio on receive.
Older tube radios routes the cathode of a one or more tubes through
the mic connector to control transmit.

2-what is this suppose to do

see above

3- if the caps are not used what will be the outcome


chances are that there maybe some ac hum in the receive or transmit.

james