[R-390] "A" Versions of Military Receivers with/without Mechanical Filter...

[Todd Bigelow - PS]

ToddRoberts2001@aol.com wrote:

>In a message dated 6/8/2003 3:08:48 PM Eastern Daylight Time, 
>bratcher@pdq.net writes:
>
>  
>
>>At 11:36 AM 6/8/2003 -0700, you wrote:
>>    
>>
>>>>Can you give me an example of a U.S. military radio
>>>>receiver
>>>>with the "A" suffix that does not have mechanical filters? Yours
>>>>Truly, Todd
>>>>Roberts WD4NGG.
>>>>        
>>>>
>>>How about the TMC R-5007A/FRR-49(V). No mechanical filters.
>>>How about the Hallicrafters R-649A/URR. No mechanical Filters.
>>>Hoq about the R-274A. No mechanical filters.
>>>
>>>Need I say more?
>>>
>>>RICH  WA6KNW
>>>      
>>>
>>R274A? Never heard of it. The R274 I've got is the mil version of the 
>>Hallicrafters SX-73 with no A on the label. Which reciever is the R274A?
>>
>>What is the Hallicrafters R649? Never saw one....
>>    
>>
>
>Interesting examples BUT doesn't R-274 denote a "family" of receivers and not 
>one particular model? The R-274 series could be either a Hammarlund SP-600 
>variant or a Hallicrafters SX-73 variant - two mechanically and physically 
>different radios? There was an R-274 series, R-274A series, R-274B series, R-274C 
>series.  There was indeed an R649 receiver made by Hallicrafters. Built for the 
>Treasury Dept. and used as Coast Guard monitors. Never seen or heard of an 
>R649A. They are so obscure that Chuck Dachis is looking for one on his web page. 
>
Still? Figured he'd have one by now. Since I don't have the R649 to sit 
beside it and compare, I can't tell you what the differences are.They 
look identical from what I can tell, at least externally. Rich is right, 
though - no mechanical filters. Interesting radio, still have a ways to 
go with the restoration.

I find this one pretty interesting from Les' post:

 >R-320A/FRC Hammarlund SP-600J-4 (no x-tal frequency control)

The R-320 is the designation given to the SC-88 made by RCA. It's not at 
all similar to the SP-600 in any way(other than perhaps coverage?), 
particularly the turret assembly. SC-88 doesn't have one. Seems really 
odd how they applied this nomenclature. The SX-73 and SP-600 are at 
least somewhat similar.

Les, does that listing contain any information about diversity 
configuration(s)?

~ Boomer,  KA1KAQ  (the other Todd)