[Boatanchors] Crystal Current

[Brian Carling]

That's the key. Minimal feedback current, maximum power gain!

Best regards - Bry Carling



> On Apr 27, 2014, at 6:44 PM, D C _Mac_ Macdonald <k2gkk at hotmail.com> wrote:
> 
> A good oscillator circuit with minimal XTAL current is a tetrode such as a 6AG7 using the screen grid as the plate in a Modified Pierce circuit!
> 
> 73 - Mac, K2GKK/5 in OKC
> 
> 
> Sent from my diPhone
> 
> On Apr 27, 2014, at 17:33, "Brian Carling" <bcarling at cfl.rr.com> wrote:
> 
> That is correct. Common practice is to put a 6.3 V 60 mA lamp in series with the Crystal. A good indication of the current will be shown by the brightness of the bulb.
> 
> Best regards - Bry Carling
> 
> 
> 
>> On Apr 27, 2014, at 4:33 PM, "Jim Wilhite" <w5jo at brightok.net> wrote:
>> 
>> I am not sure what the current should be but if too much is applied you can create parasitic oscillations you don't want.
>> 
>> Jim
>> W5JO
>> 
>> 
>> -----Original Message----- 
>> 
>> The 1952 - 1962 ARRL Handbooks  recommend crystal currents be held to
>> 40ma max and preferably less.
>> While the FT-243 type is not mentioned specifically these were in
>> widespread use at that time.   HC-6/U
>> types should probably be held to something less than that....
>> 
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