[ARC5] Crystals in WWII

[Richard Hankins]

Jim,

"small topic"???

It might have been for US forces (though I doubt it).  When you look at 
radio in WWII in general, the problem of getting sets on to frequency 
was critical.   Indeed, one major defeat for the Allies - Arnhem - has 
been partially blamed on not having the right crystals to hand.

Germany radio technology was severely hampered by having no sources of 
quartz.   So they spent considerable effort in developing sets that were 
extremely stable with standard L-C oscillators.   Indeed their success 
is quite astonishing in that regard - and German radio technology was 
way in advance of anything elsewhere that I am aware of.   But think 
about it from the Allies point of view.  This effort to replace crystals 
meant that serious resources were deployed dealing with that 
problem.........rather than something else.  So they had less effort to 
develop nasty bombs, etc.

British radio during WWII was always struggling due to the difficulty of 
netting sets.  The WS38 manpack - probably the first successful HF 
manpack on the Allied side (though I haven't compared dates for the US 
kit) - always posed extreme difficulties for the operator in getting the 
beast on to frequency.   It tunes 7.3 - 9.1MHz in 180 degrees of tuning 
knob rotation - that's about 10kHz per degree of rotation - so you need 
to set it to the nearest degree to get the set roughly on frequency.  
Try doing that when you are being shot at.....

And the lack of crystal controlled sets meant that a lot of wireless ops 
had to also lug around a wavemeter - usually as big as (or bigger) than 
the radio they were trying to tune to frequency.

And finally its known that even when crystal controlled sets were 
available - the logistics of getting the right crystals to the right 
place at the right time was a nightmare......


Richard
G7RVI

On 15/03/2013 00:52, Jim Haynes wrote:
> On Thu, 14 Mar 2013, Robert  Eleazer wrote:
>
>> Anyone ever hear of this book? Sounds interesting.
>>
>> "Crystal Clear : The Struggle for Reliable Communications Technology 
>> in World War II" by Richard J. Thompson
>>
> Yeah, I've read it.  Perhaps more words than you'd want to read on a
> small topic.  There was the decision to go to crystal control on a large
> scale, requiring a big ramp-up in crystal manufacture.  The existing
> crystal manufacturers were small companies, often having designed their
> own production machinery and methods.  It took a lot of work to help
> them increase production and to get other companies into the business
> when it had been such a craft type of business.  The problem of raw
> quartz supply from Brazil was another factor, when it was being mined
> by fairly primitive methods.  Finally production reached the needed
> level, and then another problem cropped up: crystal aging.  That too
> was successfully overcome by some hurry-up research.  And there was
> some use made of crystal-grinding laboratories in the field to supply
> sufficient numbers of crystal units on the time scale needed.
>
> Jim W6JVE
>
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