I read the PDF about the HP 4191A from Coilcraft and didn't see anything
out of the ordinary excapt some LCR meters bound to not to be calibrated.
Either this or they were used to measure an inductor outside of their range.
In any manual that comes with any decent LCR meter, they tell you that
the measurements are frequency dependant, and that the frequency has
to be changed according to what range your in. If the meter measures a
false reading after this, it is out of calibration. If the meter has a range
that
says it will measure a certain device, then it should as it has to be calibrated
to measure on at that frequency. If I recall, the Tektronix one was an older
style LCR meter with a low frequency range. The Meguro's, I'm not familiar
with as to how they work (two wire or four wire, etc). It's funny they didn't
compare the 4191A to a General Radio (GenRad) or a ESI (Tegam) which
makes measuring L, C, and R their specialty. All this whole text showed
was that the 4191A had a 100 MHz measurement function available, nothing
more. It also showed that if the Tek, Meguro, Boonton, and the other HP said
they would measure the device, they was either out of calibration or someone
was trying read a device outside their range in my opinion. I'll guarantee you
that if HP said the 4192A would measure a certain device, it would before it
left
the factory as they are one of the few direct NIST traceable labs available.
I'll also
guarantee that a precise NIST traceable standard was used to calibrate it at
HP too. After it left, it's untelling who may have had their fingers in it. If
it
measured a device correctly there, it should at another location.
Best,
Will
*********** REPLY SEPARATOR ***********
On 8/6/06 at 6:13 AM R L Measures wrote:
>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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>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>
>R L MEASURES, AG6K. 805-386-3734
>r@somis.org
>
>
>
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