[Milsurplus] Carbon Mic Subs

[Jack Antonio]

A microphone that I find works well for
some applications is either a TS-13 or TS-15
handset.  Sounds good, and has plenty of
output.

However, there is a problem using it
with some sets.  It works well with
an ART-13, but not a BC-375.

In the TS-13/15 the low side of the mic
element is directly connected to the
key line. In a T-17, the keying circuit
and the microphone circuit are both
opened on receive.

Microphone DC in the -375 is derived from
a voltage divider. Plugging the TS-13/15
into the transmitter is OK, but there is
enough current flowing through the relay
coil, mic element and the low end of the
voltage divider, to keep the relay keyed
when the switch is released.

I run the microphone in the -375 through
a BC-366 jack box, so have to switch
off liason and back again to open up
the circuit.

But it does sound better than a T-17.

Jack Antonio WA7DIA/4