[ARC5] How do I operate a SCR-274N system that's wired together?

[Mike Morrow]

Jay asked about the BC-451-A:

>Isn't there an adjustable stop on this switch to limit its
>function if only Voice is desired?

I have never seen such a version.

The most common AN/ARC-5 transmitter control box, the C-30A/ARC-5,
has a stop that can limit the transmitter select switch from being
placed in positions for which there is no transmitter.  Usually,
there were only two transmitter in the rack, so the stop would be
set to prevent the select switch from going past the "2" position.
The mode select switch on the C-30A was placed in VOICE and a cover
was screwed down to prevent alteration.

Other control boxes such as the C-38/ARC-5 had switches that had
stops to limit the switch selection, and had covers for the whole
switch when it was not be used in a particular installation. For
most AN/ARC-5 systems, these switches were covered.

But no such devices have I ever seen on an ARA/ATA or SCR-274-N
control.

This brings up another issue.  In a system with only ONE transmitter
that will be used ONLY on VOICE, the transmitter control box is
completely superfluous.  There is no need to select a different
transmitter or change mode, so the only transmitter control needed
is the PTT switch on the microphone.  A PL-153 connected to the BC-456
with the appropriate jumpers can make the appropriate connections as
the BC-451-A would make in VOICE mode and transmitter number 1 selected.
That was done in some military single transmitter AN/ARC-5 systems.  Whoever
hooked up the system in Tom's single-transmitter example should never have
bothered using a BC-451-A at all.

Mike / KK5F