[Milsurplus] BC-348 OSC temperature capacitors

[John Hutchins]

Bob -
I would agree with your assumption.  I have never found a write up on 
how the Oscillator temperature sensitive capacitor specifications were 
initially "resolved".
Also the banding. specifications, on these capacitors were not published 
in the TM manual.
Thanks
Hutch
On 2/8/2013 8:05 PM, Bob Camp wrote:
> Hi
>
> I very much doubt there was any per-radio select process at all going on at the rate BC-348's were produced. The testing and adjustment would have been *very* expensive.
>
> Bob
>
> On Feb 8, 2013, at 7:26 PM, John Hutchins <jphutch60bj at gmail.com> wrote:
>
>> Group -
>>
>> I don't know much about, temperature Compensating Capacitors, for the BC-348 receivers
>>    Were they carefully chosen for each production lot or unit as the case in the Collins Oscillator for the R105A/ARR-15. I will assume most likely not.
>>   1.  Listings in TM for ceramic capacitors did not document the temperature coefficients.
>>   2.  Listings in TM for mica Capacitors, postage stamp did not document the temperature characteristics, temperature ranges.
>>   Brings my questions 3, three:
>>   1. How they were chosen, any RCA articles on this?
>>   2. Were these capacitor temperature specifications set, specified, once for each BC-348 model production line, that was that?
>>   3. If I needed to replace one of these temperature Compensating Capacitors,  capacitors listed below, are these equivalent to NPO's of today?
>>
>>
>> TO2012R2-3BC-112_BC
>> Reference page 7-10 parts for temperature compensating capacitors for BC348R == ++
>> 40++ Capacitor: Mica 500volts DC 4.1 mmfd +-.2mmfd with lugs  | Osc. Temperature Compensating| Mgf: UE |
>> 41++ Capacitor: Mica 500volts DC 4.2 mmfd +-.2mmfd with lugs  | Osc. Temperature Compensating| Mgf: UE |
>> 42     Capacitor: ceramic 500volts DC 20 mmfd +-5%  with leads | Osc. Temperature Compensating| Mgf: CRL |
>> 43     Capacitor: ceramic 500volts DC 65 mmfd +-5%  with leads | Osc. Temperature Compensating| Mgf: CRL |
>> 44     Capacitor: ceramic 500volts DC 90 mmfd +-3%  with leads | Osc. Temperature Compensating| Mgf: CRL |
>> 45     Capacitor: ceramic 500volts DC 35 mmfd +-5%  with leads | Osc. Temperature Compensating| Mgf: CRL |
>> 46     Capacitor: ceramic 500volts DC 40 mmfd +-5%  with leads | Osc. Temperature Compensating| Mgf: CRL |
>> -Thanks
>> Hutch
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