jimlux wrote:
>Steve Hunt wrote:
>> Paul,
>>
>> I made the measurements myself. The inductor was in the open, sitting on
>> a wooden baseboard. It had a "tapered pitch".
>>
>> The Qs I measured seem to be similar to those measured by Tom W8JI who
>> says this on his web site:
>>
>> "The trend of Steve's data agrees with my measurements, although there
>> are differences in data because I measured different inductors. I
>> measured less peak Q, but also significantly higher minimum Q in the
>> inductors I tested. While the inductors I measured has less delta in Q,
>> they also had a serious dip in Q up near 25-35 MHz when near
>> half-inductance."
>>
>
>What were the physical dimensions of the inductors? Any estimate of
>the self C? (on a tapped inductor, you can use a Medhurst approximation
>to get within 5% or so).. the self C can make the "inductance as a
>function of turns or length" be kind of weird, particularly near self
>resonance.
When calculating tuner losses we need two separate parameters, Rs (the
loss resistance) and X (the effective reactance, with capacitive effects
*included*). Combining these into a single "Q" value is not necessary,
and only creates new ambiguities.
--
73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek
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