[600MRG] inductor measurements

[Edward R Cole]

At 12:32 PM 9/28/2015, Edward R Cole wrote:
>=======snip
>
>Upgrading my Elecraft K3 to operate below 490-KHz cost me $468.95 
>but has other benefits other than just enabling operation down to 
>100-KHz.  It benefits operation in highly crowded HF bands (which I 
>don't do much) and lowered VFO phase noise which improves 
>weak-signal performance (which I do).
>
>It may even be at the PO today!

They arrived: two SYN3A synthesizer boards and one KBPF3 modification 
kit to expand general coverage band filter down to 100-KHz.

It will be awhile till I install these and I'm piled under with 
making five DEMI kits this month (Oct.).  Leaves are all now yellow 
and its been raining several days (predicted snow tomorrow - too soon 
to stick).


>73, Ed - KL7uW
>
>At 10:34 AM 9/28/2015, Rudy Severns wrote:
>>Frank is right on the mark.
>>
>>
>>
>>You have to be careful when measuring inductor characteristics if you want
>>accurate results.  If you have a Q-meter it's very instructive to mount the
>>coil in place, measure the Q, and then place a sheet of copper board or
>>aluminum at various distances around the coil.  When you place a conducting
>>sheet close to the coil the Q-meter reading will drop dramatically but
>>that's mostly detuning from resonance.  You have to re-peak the Q to see the
>>actual effect on inductor Q.  You can also use this approach to check on
>>coupling between coils, etc.  This can be of great help in selecting an
>>enclosure and for layout within filters.  The Q-meter will also let you
>>determine the inductance at a given frequency.  Even in an air wound core
>>the inductance will vary with frequency and there will be issues with
>>self-resonance.  This can be an issue with the large inductances needed for
>>very small antennas.  The Q-meter is a multi-purpose tool.
>>
>>
>>
>>73, Rudy N6LF
>>
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>
>73, Ed - KL7UW
>http://www.kl7uw.com
>     "Kits made by KL7UW"
>Dubus Mag business:
>     dubususa at gmail.com
>
>
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73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
Dubus Mag business:
     dubususa at gmail.com