[R-390] Some Crystal Info

[Tom Norris]

I've ordered several milspec crystals from International Crystal  
(ICM) by just giving them the frequency and the spec #.  They were no  
more expensive than any other new crystal.  I rue the day I come  
across a bad cal oscillator crystal.

There are a couple other crystal sources I've used that are maybe $5  
less than ICM, I'll see if I can dig them up.

Tom NU4G


On Oct 23, 2007, at 1:43 PM, ANTHONY CASORSO wrote:

> It's funny how these things happen. I looked all over for info  
> about these crystals several times. Now that I made that post  
> yesterday, suddenly I can find it easily.
>
> I'm not sure if links are OK in a post here. There is a good pdf  
> with a table of all of the military CR types and their specs at
>
> www dot euroquartz dot co dot uk slash pdf slash cr-crystals.pdf
>
> Tony
>
>
>
>
>> From: Bob Camp <ham at cq.nu>
>> To: Tony Casorso <canthony15 at msn.com>
>> CC: <R-390 at mailman.qth.net>
>> Subject: Re: [R-390] Some Crystal Info
>> Date: Tue, 23 Oct 2007 07:47:49 -0400
>>
>> Hi
>>
>> If you rummage around long enough, there is a military  
>> specification  on all of the crystals in the R-390. It's pretty  
>> specific about the  load, temperature, and tolerance of each  
>> crystal. They even go into  stuff like spurs, resistance, aging,  
>> and  motional parameters. What  makes it *very* confusing is that  
>> after the military standardized  everything we all started using  
>> the mil designations to refer to the  crystal packages rather than  
>> what's inside ....
>>
>> All of the military crystals were designed under contract out of  
>> Ft.  Monomoth. The agency involved changed names so often it's  
>> sometimes  tough to figure out who is who. Some of what was done  
>> is reported in  the Proceedings of the Frequency Control  
>> Symposium. A lot of what was  done was published in separate  
>> reports. Most of those are *tough* to  find these days.  
>> Occasionally you will find references to them in the  FCS papers.
>>
>> Bob
>> KB8TQ
>>
>>
>> On Oct 22, 2007, at 10:42 PM, Tony Casorso wrote:
>>
>>> Hi everybody. Sorry that my image thread got so long. I'm still   
>>> looking at the problem but I'll keep the details to myself and  
>>> only  post here if I make some headway.
>>>
>>> For a while now I've been wondering what the difference between  
>>> a  CR36/U and a CR27/U crystal was. I found a reference to them  
>>> in an  old paper that is only available to paying members of  
>>> IEEE. I  believe the paper is from the 1950s as it is full of  
>>> tube  oscillator circuits. I started a new job in July and it  
>>> turns out  that I have access to all of the IEEE papers. This one  
>>> is called  "Design Data for Crystal Oscillators" By H.E. Gruen of  
>>> the Armour  Research Foundation. It says that the CR18/U, CR27/U,  
>>> and CR36/U  crystals are all designed for 32pf loads to be used  
>>> in parallel  resonant mode (antiresonant mode in the paper). The  
>>> difference  between them is that the CR18/U is not for use in  
>>> ovens while the  CR27/U is for oven applications at 75 degrees C  
>>> and the CR36/U is  for oven applications at 85 degrees C.
>>>
>>> Hopefully someone will find this information useful.
>>>
>>> Cheers,
>>>
>>> Tony
>>>
>>>
>>>
>>> _____________________________________________________________
>>> R-390 mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>>> Help: http://mailman.qth.net/faq.htm
>>> Post: mailto:R-390 at mailman.qth.net
>>> Unsubscribe: http://mailman.qth.net/mailman/options/r-390
>>>
>>
>
>
> _____________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/faq.htm
> Post: mailto:R-390 at mailman.qth.net
> Unsubscribe: http://mailman.qth.net/mailman/options/r-390

Tom Norris
R390A at BellSouth.net

"Just because your children were born in the South does not make them  
Southerners. After all, if a cat had kittens in the oven, that  
wouldn't make them biscuits."