[ARC5] Crystal Tester

[Richard Knoppow]

    I will have to try finding one of the technical manuals.  Thank you 
for the explanation.

On 6/12/2016 10:40 PM, Fuqua, Bill L wrote:
>   If you look at some of the military crystal impedance meters the usual way they work is by having a tuned non-inverting amplifier with a crystal
> in series between the input and output. This makes the crystal oscillate in the series resonant mode. The current is measured thru
> the crystal and then you can substitute a resistor for the crystal, not changing the frequency of the amplifier, and adjust the resistor until
> you get the same current. This  is the series resistance.
>   You can measure the frequency with a counter. And the if you can measure the Q you can calculate all the other parameters such as
> the motional inductive and capacitive reactance.
>   I have an old military crystal impedance meter but now  use by digital ones.
>
> 73
> Bill wa4lav
>
> ________________________________________
> From: ARC5 [arc5-bounces at mailman.qth.net] on behalf of Richard Knoppow [1oldlens1 at ix.netcom.com]
> Sent: Monday, June 13, 2016 1:20 AM
> To: arc5 at mailman.qth.net
> Subject: Re: [ARC5] Crystal Tester
>
>     There must surely be instruments which will do this. An ordinary
> Boonton Q-Meter would not without some help since it will measure Q up
> to about 1000 and crystals have Qs of perhaps then times this or more.
>
> On 6/12/2016 10:07 PM, Fuqua, Bill L wrote:
>>    What is needed is a simple measurement of series resistance and Q.
>> 73
>> Bill wa4lav
>>
>> ________________________________________
>> From: ARC5 [arc5-bounces at mailman.qth.net] on behalf of Kenneth G. Gordon [kgordon2006 at frontier.com]
>> Sent: Sunday, June 12, 2016 10:49 PM
>> To: Arc5 at mailman.qth.net
>> Subject: Re: [ARC5] Crystal Tester
>>
>> On 12 Jun 2016 at 21:37, Robert  Eleazer wrote:
>>
>>> Also crystal tester articles in 73 mag, August 1996 and Nov 1971.   The Aug 96 article
>>> includes some advice on how to restore FT-243 crystals to operation.
>>
>> Both of those are solid-state circuits with voltages and currents too low (IMHO) to
>> adequately test FT-243 or other large crystals.
>>
>> But thanks for the links anyway.
>>
>> Ken W7EKB
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>
> --
> Richard Knoppow
> 1oldlens1 at ix.netcom.com
> WB6KBL
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-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL