[Amps] grid resonance

[R L Measures]

On Aug 5, 2006, at 10:52 AM, Tom W8JI wrote:

>
>> For those interested, see
>> http://www.aade.com/lcm2binst/coilcraft%20L%20measurement.pdf
>>
>> A number of inductance meters are tested in the article
>> and it seems that many of them lie, because of the method
>> used.  The article, by Coilcraft, also covers the use of
>> grid dip meters.
>
> CoilCraft says:
>
> "The Hewlett Packard HP4191A is emerging as the new
>
> standard for inductance measurements of RF coils. The
>
> HP4191A has an accuracy that can be better than 1%"
>
>
>
> I guess I won't be trading my 4191A in for a GDO anytime
> soon, although I am puzzled why my GDO can't read grid dips
> by holding it near socket pins of transmitting tubes.

My Trio-Kenwood dipmeter reads grid dips.  For example, when it is  
grounded, a 3-500Z grid dips c. 88MHz .
- note - With all three grid pins of a 3-500Z grounded, there is an  
additional dip between grounded pins.  To get a clearer idea of  
what's what, strap only pin to ground and make a sweep.
>
>
>
> The HP4191A shows negligible difference between identical
> suppressors, one made with nichrome and the other tinned
> copper, at VHF.
>
>
>
> 73 Tom
>
>
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R L MEASURES, AG6K. 805-386-3734
r at somis.org