[Milsurplus] N-1 Carbon Mic Element and T-17s

[Jim Haynes]

It's my belief, unsupported by any evidence, that the T-17 microphones 
were intentionally very non-sensitive so that the user would shout into
them over the ambient noise in the airplane.

There is a paper out covering the official Western Electric method for
rejuvenating carbon transmitter elements.  I've attached it, but in case
the attachment doesn't survive the mail system, here's what it says.

Connect a 6.3V transformer output to the element in series with a 500 ohm
1 watt resistor.  Holding the element vertical, rotate it through 120
degrees in both directions for one minute while the current is applied.
Do not hit or tap the element and do not allow it to overheat.

While the AC current is on, blast the microphone diaphragm with acoustic
white noise for a minute or two.  The person who submitted this suggests
noise from a handheld transceiver speaker held against the element; but
you can think of other things.

Procedure may be repeated 2-3 times if necessary.



jhhaynes at earthlink dot net