[Milsurplus] More Problems with the "VHF Primary" Myth:

[Al Klase]

You might check out:

*"Crystal Clear:  The Struggle for Reliable Communications Technology in 
World War II"  by Richard J. Thompson, Jr.

See:  
http://www.wiley.com/WileyCDA/WileyTitle/productCd-0470046066,miniSiteCd-IEEE2.html

I heard this guy's lecture at InfoAge recently.  It was interesting.  
The book is on the expensive side, and I was disappointed that a lot of 
radio gear in the photos was mis-represented.  I have a copy on loan 
from the InfoAge Library, but haven't go to reading it.

Regards,
Al
*
Bob Camp wrote:
> Hi
>
> That paper is an interesting, but far from complete study of the 
> crystal situation in WWII.
>
> Bob
>
>
> On Jul 18, 2008, at 3:55 PM, David Stinson wrote:
>
>> The operational problems with WWII aircraft VHF sets lasted longer 
>> than has generally been accepted,
>> again proving that aircraft VHF during the war was "not ready for 
>> prime time"
>> and in no shape to "replace" any system during the conflict. The 
>> "crystal shortage" issue, which dogged the first half of the war,
>> was replaced by the "crystal aging" issue, which resulted in drift 
>> and activity failure.  These problems with supplying
>> the Air Corps with good VHF crystals continued past the end of the war.
>> From:
>> IEEE Proceedings of the 35th Annual
>> Frequency Control Symposium, pp. 3-12, 1981
>> "A HISTORY OF THE QUARTZ CRYSTAL INDUSTRY IN THE USA"
>>
>> "...
>> The Ageing Problem
>> By the middle of 1943 the task of setting up an industry was complete 
>> and crystal units were being produced in numbers adequate to meet the 
>> demand. It was then that the second, and even more serious crisis 
>> confronted the crystal program. Reports began to filter in of 
>> extensive crystal failures both in service
>> and in depot storage. The first responses to these reports ranged 
>> between indifference and disbelief.  However, the reports became more 
>> persistent and the Signal Corps Engineering Laboratories (SCEL) at 
>> Fort Monmouth were requested to investigate the situation.
>> The progress was slow because the problem was treated as an academic 
>> question rather than a matter of the utmost urgency. Late in 1943 a 
>> telegram was received at OCSIGO which changed the situation. It read 
>> as follows:
>>
>> COMMUNICATIONS EIGHTH AIR FORCE BASED IN BRITAIN BROKEN DOWN LACK OF 
>> CRYSTALS FIND CAUSE CURE SAME EAKER
>>
>> ... tests quickly confirmed the field reports. All crystal units 
>> failed within a few days or at most a week or two...
>> the ageing syndrome (was) characterized by loss of activity
>> and increased frequency. Many theories were advanced to explain the 
>> phenomenon and these had to be checked out experimentally. Meanwhile 
>> the manufacturers were producing crystal units at
>> the rate of a million per month; nearly all of which were destined to 
>> be useless....
>> The problem of ageing was especially severe in the CR-1 unit used by 
>> the Air Force ...
>>
>> Consequently a Conference of all Crystal Manufacturers was called on 
>> July 11-12, 1944....
>> The problem was explained in detail and the proposed remedy was 
>> presented.... Ironically, the ageing problem might have been avoided 
>> had better communication existed. The phenomenon of ageing had been 
>> noted as early as October 1940 at RCA...
>> At home teams of GI's and civilians were trained to examine depot 
>> stocks of crystal units and to select out useable units which were 
>> often flown immediately to a war theatre. Later some attempts were 
>> made to salvage the defective units and at least one company, The 
>> Hudson American Co., was commissioned to do so. However most of the 
>> units were enclosed in phenolic plastic holders and many others 
>> contained brass contacts, both of which were considered unsatisfactory,
>> leaving little besides the quartz blank to be salvaged. It soon 
>> proved to be uneconomical to salvage the units and ultimately 
>> millions of the unetched units were destroyed...."
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-- 
Al Klase - N3FRQ 
Flemington, NJ 
http://www.skywaves.ar88.net/