[Milsurplus] ARC-5 data tags...

[Mike Hanz]

Kenneth G. Gordon wrote:

>I have had several ARC-5/ARA receivers where the data tags on the top 
>case have the date section excised from the tag, leaving a rectangular-ish 
>gap.  Why was this done? Strange...  Anyone know?
>

I've seen it done on a few early ARA and ATA sets, but never on an 
SCR-274N or ARC-5 set.  The reasoning is best explained in a book on 
radar, surprisingly enough.  In 'Instruments of Darkness' (IIRC), there 
is an excellent excerpt on the intelligence value of captured German 
electronics, which had painstakingly dated records of repairs inside the 
sets.  Comparing sets captured at various points in the war, they showed 
technology changes, problem solutions, material substitutions, etc. 
which the British were able to effectively exploit or add to the growing 
intelligence picture. The US sets you will find most frequently with 
this modification are those carried by long range Navy patrol aircraft 
early in the war, since they had the greatest potential for being 
captured.  Thus, the ARA/ATA, RAX-1, ATC, ATD, GO-9, GP-7, etc. 
frequently have that section milled or ground off of the tag.  By the 
time the SCR-274N and ARC-5 had arrived, such effort was apparently 
considered overtaken by events, since it was clear the Allies would win 
the war.  I think it was partially dependent on the Service involved, as 
well - the Signal Corps didn't seem to consider it as much a threat as 
the Navy, at least based on my meager sampling.

73,
Mike