[R-390] Scale varies band to Band

[Gordon]

Hi Bob,
Well, That explains it. Sure would have been nice if they had put 
trimmers in there though. LOL
I don't have any "Extra" Crystals, so looks like it will be a while 
before I can find all that closely match..hi hi..
Another Question, What makes a crystal go Bad..ie (Stop working)? Isn't 
it just a piece of Quartz ?

Gordon N6WK


On 5/13/2013 2:51 PM, Bob Camp wrote:
> Hi
>
> A *long* time ago I ran into the guy who designed the oscillator deck in the R-390A. When asked "why no trimmers?" the answer was - It wasn't in the spec. Put another way, they could do everything they needed to do without them, and they cost money ….
>
> If you can come up with a big enough pile of crystals, you can sort them into groups that match fairly well. It's a time consuming process and should be done tin the radio you will be using them in.
>
> Bob
>
> On May 13, 2013, at 4:42 PM, Gordon <gordon at n6wk.com> wrote:
>
>> Is it normal for the scale to vary a couple Kc's band to band?
>> For example, If the Calibrator is dead on 7.500 on the 7 Mcs band, is it normal for it to be maybe on 8.502 on the 8 Mhz band and maybe 9.497 on the 9 Mhz Band?
>> I do not see any trimmers to bring each crystal dead on. Am I missing something?
>>
>>
>> Thanks,
>> Gordon
>> N6WK
>>
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