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The AN/ARC-4 set was known in the civilian world as the Western Electric 233A. It covered the 140 to 144Mc band,
and had a power output of about 7 Watts from an 832 modulated by a pair of 6L6s. The transmitter and receiver are crystal
controlled by pairs of crystals in single holders. There are three plane-to-ground channels and one plane-to-plane channel.
The receiver has two front ends and is capable of monitoring the plane to plane channel, one of the three plane-to-ground
channels or the plane-to-plane channel and a plane-to-ground channel simultaneously. The set provided an interphone
function for the air crew as well. 13.5 Volt, 27 Volt, and dual 13.5/27 Volt dynamotors were available to power the set.
The first implementations of the set were of the WE 233A incarnation, and may have not been sanctioned officially by
the Navy.
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| ARC-4/ARC-1 Mount |
The same mount is used for either ARC-4 or ARC-1 transceivers, but the wiring is different. The connector is inverted
when wired for one or the other.
The configuration for ARC-1 transceivers was a clue that the ARC-4s on BB-59 had been replaced by ARC-1s at some point.
Confirmation was found in the Combat Information Center, where ARC-1 remote controls were found, and on an equipment inventory.
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| 28-Volt Supply in VHF Compartment USS MASSACHUSETTS |
This ship-built supply probably goes back to the initial installation of WE 233A equipment. It uses open-frame
transformers that appear to have been wound on the ship, and Tungar rectifiers. Tungar rectifiers were commonly used
in battery chargers of the time.
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| RT--18/ARC-1 With Front Cover Removed |
The AN/ARC-1 set came out later than the ARC-4. It uses mostly miniature tubes and is a much more sophisticated
set. It is the earliest set I am aware of that uses one crystal to determine the frequency of each channel, with a common
crystal at the IF frequency that is mixed with the channel crystal to get receiver injection.
ARC-1 has ten channels, one of which is a guard channel that can be monitored along with one of the others, or seperately.
The frequency range is 110 to 156Mc, and the transmitter power output is 8 Watts, AM mode. The power supply is 28Volts
to run an internal dynamotor.
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| Inside of Front Cover of RT-18/ARC-1 |
Many RT-18s are found without the front cover, which has the useful tuning chart to get you started on tuning it up,
and the very useful tuning tool. With the tuning tool, the tuning is touchy. Without it, you need to have really
steady but strong hands.
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