[R-390] Crystal 200 KC

Patrick brookbank at triad.rr.com
Mon Feb 25 08:52:54 EST 2008 

Thanks Bob, it was very informative. For what is worth, yesterday, looking 
around my "yunk" pile, I found seven 8 pin ovens with 200 kc crystal in 
them, (BLILEY ELECTRIC CO: ERIE PA) 26.5 volts .3 A 75 Celcius. I took the 
crystal out and checked them on a signal generator that has a crystal 
checker. They are all right on the money. I guess I did find a small 
treasure. Regards....Pat
----- Original Message ----- 
From: "Bob Camp" <ham at cq.nu>
To: <wb5uom at hughes.net>
Cc: <r-390 at mailman.qth.net>
Sent: Sunday, February 24, 2008 10:10 PM
Subject: Re: [R-390] Crystal 200 KC


> Hi
>
> I"m not sure that we all understand just how unusual a crystal the 200  KC 
> rock really is.
>
> Most of the crystals in the R-390 are AT cuts. They are as common  today 
> as they were back when the radio was new. Quartz is grown  oriented to 
> make cutting AT blanks efficient and cheap. You can buy  cut to spec 
> blanks from companies in at least a dozen countries.  That's true weather 
> you want to buy one or a million pieces. There are  hundreds of companies 
> worldwide that can and do make AT's that are  capable of being dropped 
> into an R-390.
>
> Below 1 MHz AT's become impractical. A number of other cuts are used.  The 
> raw quartz needs to be oriented correctly for each cut. The blanks  get 
> big and the cutting becomes difficult. To really appreciate what  all that 
> means you have to get into some nasty physics. Forty years  ago there 
> where maybe ten to twenty people in the world who actually  did it. That's 
> not companies, I indeed mean people who could set the  cutting up.
>
> Next up is that people have simply stopped making crystals below 1 MHz 
> the way they used to do it. The approach now is to use a tuning fork  or 
> flex bar that uses enormously less quartz than the old cuts did.  Your 32 
> Khz watch crystal is one example. It would not sell for 3  cents if they 
> hadn't done an enormous change in it's design. You could  make 500 watch 
> crystals out of the quartz in one old style crystal.
>
> By making the crystals smaller they changed their characteristics. The 
> electrical performance of the tiny crystals is very different than the 
> big old ones. They don't work in the same circuits.
>
> Finally this is an oven crystal. It's temperature characteristic is 
> *very* different than a room temperature crystal. That makes it a rare 
> bird in a rare flock of birds.
>
> Most of the low frequency work in this country ten to twenty years ago 
> was going into 455 KC crystal filters. What ever is left of that  effort 
> is bits and pieces. Adapting a filter crystal setup to chop  200KC 
> frequency standard crystals is going to be a real chore.
>
> When I asked the guy at Collins *why* he designed this crystal into  the 
> R-390A, his answer was simple - "we were sold a bill of goods".  Oddly 
> enough through the course of many mergers I now work for the  company who 
> sold him that bill of goods ... small world. ...
>
> We haven't made those crystals in 20 years.
>
> Hang on to any of these you have. If you part out a radio, keep the  200 
> KC crystal. Unless you want to cobble something together, they  will be 
> the death of more radios than dead power transformers.
>
> Bob
>
>
>
> On Feb 24, 2008, at 6:12 PM, <wb5uom at hughes.net> <wb5uom at hughes.net> 
> wrote:
>
>> I got in on the tail en of this I guess. You might try (for grins):
>> http://www.icmfg.com/crystals.html#ranges
>>
>> Now I know they are not really interested in selling just one or two  BUT
>> I called a place one time looking for ONE special intergrated chip,  not 
>> a
>> 1000 or 10,000 just ONE. I called them and the lady said they didnt  sell 
>> in
>> that small of quanity BUT if I was doing a pilot project they would  send 
>> me
>> 1- 20 for FREE !!
>> It took me just a microsecond to affirm this was a "pilot" project !!!
>> Have plenty of spares now!
>>
>> So, it might not hurt to make a call!
>>
>> David/WB5UOM
>>
>>
>> ----- Original Message -----
>> From: "Bob Camp" <ham at cq.nu>
>> To: <roy.morgan at nist.gov>
>> Cc: <r-390 at mailman.qth.net>
>> Sent: Sunday, February 24, 2008 4:39 PM
>> Subject: Re: [R-390] Crystal 200 KC
>>
>>
>>> Hi
>>>
>>> The problem with the 200 Kc crystals is that they are not a "normal"
>>> low frequency cut. You have to chop quartz at a special angle for  oven
>>> crystals at that frequency.
>>>
>>> It's not going to be easy to find somebody doing that.
>>>
>>> Bob
>>>
>>>
>>> On Feb 23, 2008, at 10:31 PM, roy.morgan at nist.gov wrote:
>>>
>>>> Quoting Patrick <brookbank at triad.rr.com>:
>>>>
>>>>> Wow, the last post went OK ok, could someone let me now a source
>>>>> for a 200
>>>>> kc crystal and aprox. the cost??? Thank....Pat
>>>>
>>>> Patrick,
>>>>
>>>> There have been found one or two souces of low frequency crystals.
>>>> Most
>>>> manufacturers will not make them any more.
>>>>
>>>> There have been reports of one fellow in Mexico I think, but I don't
>>>> have any
>>>> info on that source.
>>>>
>>>> The only other one reputed to make low frequency crystals is:
>>>>
>>>>
>>>> Universal Crystals Inc.
>>>> Jim Little
>>>> Private Company, Headquarters Location
>>>> 5407 Payne St., Shawnee Mission KS 66226,
>>>> United States
>>>> (913) 334-6254,
>>>> Line of Business: Manufacturing: Quartz crystals
>>>>
>>>> Here is the source of my information:
>>>>
>>>> To: <PHIL13 at STNY.RR.COM>; "Collins Reflector Posting"
>> <collins at listserve.com
>>>>>
>>>> Sent: Friday, July 01, 2005 12:46 PM
>>>> Subject: Re: {Collins} xtal-75a-1
>>>>
>>>> At 03:52 PM 6/30/2005, you wrote:
>>>> Is there a source for the 500 kc xtal for the 75a-1? or does someone
>>>> have one to
>>>> sell?
>>>>
>>>> Phil and others,
>>>> I have just gotten the following from Glenn Nash about a source for
>>>> low
>>>> frequency crystals:
>>>>
>>>> "Mel" is the guy at:
>>>> www.mhelectronics.com.  (800 643 9825)
>>>>
>>>> Mel said that the best guy on the planet for those is : Universal
>>>> Xtal in
>>>> Kansas City, phone 913-334-6254 ask for Jim Little.
>>>>
>>>> I called Little and lo and behold he says he bought up just about
>>>> every low
>>>> frequency xtal blank in the US and is at this very minute cranking
>>>> out a bunch
>>>> of 455KC types. They are a bit expensive, around $50, but less than
>>>> half what
>>>> International Xtal gets for their low freqs.
>>>>
>>>> Try to contact  "Mel" and let us know what you find out, please.
>>>>
>>>> Roy
>>>>
>>>>
>>>> Roy Morgan
>>>> 13033 Downey Mill Road
>>>> Lovettsville VA 20180
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>>>
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>>
>
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