[Milsurplus] GRA-53 / GRA-54

[COURYHOUSE at aol.com]

we put a vrc version in the wing commanders  car at  Luke AFB  !  ca. 1970s 
 early...
Ed Sharpe archivist  for smecc
 
 
In a message dated 9/1/2016 8:54:27 A.M. US Mountain Standard Time,  
ka2ivy at verizon.net writes:

I worked  on the GRA-53 in the US Air Force in 1970-71. Because of the 
markings and  manual, I knew there was a mobile version as well, but did not see 
one until I  got one of my own years later. The main repair problems were 
caused by the  tantalum condensors in the transceiver shorting out, usually 
causing an  obvious or total failure and easy to find and repair. They ran 
HOT, and in  southeast Asia that was exascerbated by the climate. In an air 
conditioned  room it was managable. The worst problem with them and their 
cousins the ARC  and GRC-27 was getting them to work to book and inspection 
specifications.  They would easily  produce 90% of output power and break 
squelch at 3.2  microvolts day in day out for months, but getting them to 100% of 
output and  under 3 microvolts sensitivity was for all practical purposes 
impossible.  Massive tube replacements and re-alignment (DAYS of tweaking,  
praying,  and sometimes cursing) would get them to produce 100.5% of rated 
power and  break squelch at 2.999 microvolts for a day or so, pass inspection, 
and quell  the lifers. They WILL work on the 220 Mc band if the trimmers on 
the wideband  tuners are tweaked. It is also possible to use them as a 
transverter for AM or  FM.   I have tried to entice some locals to get something 
going on  the  220 band, but no one seems to care around here.  I KNOW! it's 
 really 222-225, but like to say 220 to let "them" know  the loss of the 2  
megs is remembered, the new uses are a failure, and they  should be  
returned.

Bruce Gentry, KA2IVY  


On 9/1/16 11:05 AM, antqradio at sbcglobal.net wrote:



The  above are similar to the VRC-24, TRC-68 and URC-9 UHF multi-channel  
transceivers of the late 1950's and early 1960's.  The VRC-24 and the  TRC-68 
share a common manual but the URC-9 is in a class of it's own  although it 
is the same RT unit with a slightly different die-cast front  panel, is in 
grey instead of OD and of course, Navy.


I  am curious about the heritage of the design.  If  one goes by RT 
numbers, then it seems that the sequence is:


VRC-24  with RT-323
TRC-68  with RT-441
URC-9  with RT-581


But  I have no idea where the GRA-53 and GRA-54 fit into the lineage.  When 
 I was in the Air Force and stationed at Mactan, AB, Philippians in the 
late  1960's, I worked on TRC-68's, GRA-53's and GRA-54's.   Long after I was  
discharged I learned about the VRC-24 and URC-9 versions.


If  anyone is lucky enough to have examples of the GRA's in their 
collection,  could you please send photos of the nomenclature tags on the RT unit, 
power  supply and case?  Stories about working on these beasts are also  
welcome.  Anyone have the extension cable that allows operation of the  RT unit 
outside of the case?


Thanks  in advance, 
Jim



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