[Milsurplus] Opinions on ARR-7

[Mike Hanz]

On 8/28/2012 9:57 AM, Ray Fantini wrote:

> With all this discussion of counter measurements receivers I would propose that the Hallicrafters designed receivers were a product line that although they filled a need was a product line that went nowhere.

Many people aren't aware that Hallicrafters was actually an important 
ECM development company through the late 1960s.  It later became part of 
Northrup.  The AN/ARR-5 was a workhorse that is listed in the standard 
equipment compliment for the RB-36 in 1953. So, I'm not sure one could 
say that the product line went nowhere. It, like every other product 
line, underwent evolution with technology and threat.  The ARR-7AX was a 
miniature tube version of the classic SX-28 and persisted in USAF 
aircraft through the early 1950s.

>   The entire ARR family was obsolete and surplus by the end of the war and the future was the APR-4 series of receivers.

Well,  I have ARR-* listings through AN/ARR-23 listed as of September 
1945, and the list was still growing.  You have to remember that the 
technology was all about the threat, and the APR-4 only (belatedly) ran 
through 2.2 GHz.  By the close of the Korean war, the threats weren't 
your father's Oldsmobile any more.  The APR-4 was insensitive and clunky 
to use even with the four band tuning unit.  It produces images like you 
wouldn't believe except for the lowest freq TU, which had the advantage 
of a normal receiver front end with adequate stage filtering.  The APR-4 
usage in US aircraft petered out of common use in the mid 1950s with the 
AN/APR-4Y, though it spent a lot of time in foreign countries after 
that.  Ya gotta remember that we began flying ferret missions at 60,000 
feet by then, and it's pretty hard to tune those beasts with pressurized 
gloves on.

> Think the APR-4 and APR-1 was introduced around the same time as the Hallicrafters stuff and although the APR will not cover the low frequencies that the ARR-7 did all the ARR stuff disappeared after the war but the APR-4 went on well into the cold war and the APR-4Y was in service into the late sixties and early seventies. Although not popular with the Ham community due to the relatively low sensitivity and wide bandwidth I would propose that the APR-4 series of receivers may be one of the longest used and best counter measure receivers built. And was the choice receiver until replaced by the early Watkins Johnson/ CEI equipment in the sixties. But this is all just speculation on my part.

I guess I have a slightly different take on the technology, but others 
certainly may have different views.  I always considered the *real* long 
lasting countermeasures receiver to be the AN/APR-9 series, which began 
life as an airborne receiver component of the WWII "Elephant" jamming 
prototype.  It had receiver heads that went down into the upper HF 
region, and with the APA-69 and ALR-8 add-ons, were a part of a complete 
panadapter/pulse analysis system that covered up to 10.750GHz.  In 
Alfred Price's Volume 2 of "The History of Electronic Warfare" is 
recorded this information:  "The APR-9 was destined to be built in 
greater numbers, serve longer, and would spawn more developments than 
any other item of equipment in the history of electronic warfare...It 
would fly its first operational mission in 1947, and more than four 
decades later the equipment remains in service in several countries..."  
Its basic architecture was used for many years through countless 
follow-ons improvements.

Take a look at the innards of an APR-9 receiver some time.  With the 
complex servo cam driven tuning mechanism, it makes an APR-4 look like 
Og the Caveman made it...:-)   There are a couple of photos of the 
system at http://aafradio.org/countermeasures/APR-9.html  Note the CBY 
manufacturer (Aircraft Radio Corporation) on the labels...heh, heh...  
Not your average AN/ARC-5...

73,
Mike