[ARC5] T-19/ARC-5 & T-22/ARC-5

[Mike Morrow]

>I occasionally operate an unmodified* 7.9.1Mc TX, using the internal relay
>as keying device. Chirp is not a problem. On the other hand, the loud 
>clacking from the relay drives me nuts :)

If operated in the same manner as employed in military service, there are
*no* relays actuating in a command set transmitter as it is keyed.  The two
relays in the transmitter (K53 and K54) are transmitter *select* relays
that energize and stay energized when that transmitter is selected at the
transmitter control box.  They are not keying relays, and thus one does
not need to worry about what set of contacts close first on K53.  If
mis-used as a keying relay, then as Dave Stinson has pointed out, the
order of contact closure on K53 is critical for chirp avoidance.

The keying relay in the military configuration is K52 in the modulator.
This relay keys *all* of the HV supplies to the transmitters in the rack.
The only transmitter that responds is the one which has its select relays
energized.

To duplicate the as-designed keying of a command set transmitter, energize
K53 and K54.  Then, key *all* of the HV supplies going to the transmitter
with an external relay that simulates modulator relay K52.

Mike / KK5F