[ARC5] Need Information

[David Stinson]

Hi, Floyd!
There are three basic sets, all collectively (and incorrectly)
called "ARC-5":  
the Navy ATA / ARA,  Army SCR-274N and later "Joint" AN/ARC-5.  

The ATA / ARA can be further split into A.R.C.- and Stromberg-built.
Transmitters will fit into SCR-274N TX racks.
Receivers will fit into SCR-274N and AN/ARC-5 receiver racks.

The SCR-274N can be split into 1st-run A.R.C.-, early Western Electric-, 
late Western Electric-, Colonial- and Other-built.
Transmitters will fit into ATA / ARA TX racks.
Receivers will fit into ARA / ATA and AN/ARC-5 receiver racks.

The later AN/ARC-5 can be split into A.R.C.- and Stromberg-built.
Receivers will fit any type receiver rack, 
but transmitters will fit only in AN/ARC-5 transmitter racks.

There are also some minor makers of accessories.

While the three types of receivers are not electrically identical,
the rear connections are identical and the receivers are interchangeable.

The AN/ARC-5 transmitters are not interchangeable in other type racks 
and its connector pins are assigned differently.
However- if you are not using racks and plan a home-brew supply,
the same voltages will work with any of the transmitters
and the non-destructive keying and operation procedures are the same.

Here's a "primer" on the physical differences of the transmitters:

http://home.netcom.com/~arc5/ARC5/ARC5TXtypes.htm

The ATA and SCR-274N transmitters are electrically identical.
They have PAs which are series-fed.
In their original complete set, they were screen modulated.

The later AN/ARC-5 is NOT identical.  
The rear plugs different.  The PA is shunt fed. 
AN/ARC-5 in its original complete set was plate and 
screen modulated.  The plug on the rear was made bigger
to prevent arcing from the larger voltage peaks of plate 
modulation.

Hope this helps some.

73 DE Dave AB5S