[600MRG] s/c inductor tuning loops

[J Mcvey]

 The variometer is nothing more than a transformer with variable mutual inductance
The load will affect the Q more as the coupling is increased, but at least the energy ends up in a load!

,The tuning disk just wastes energy in heat, which is why they don't use that method any more, IMO.



    On Tuesday, May 8, 2018, 7:50:11 PM EDT, Brian, WA1ZMS <wa1zms at att.net> wrote:  
 
 I read the write up. Very interesting. That's a much great change in Q than I would have expected.  And as for the variometer case....it would help define an optimum range over which you'd want to bound the tuning range before the Q starts to suffer.
This also says the "dead end effect" of turns on a coil might have been misrepresented from tales of operators from the 1920's. hi...hi...

-Brian, WA1ZMSiPhone
On May 8, 2018, at 7:13 PM, Rudy Severns <n6lf at epud.net> wrote:



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Hello All,

  

Over the past few days there’s been some discussion of floating short circuited loops or metal discs placed inside a coil to adjust the inductance.  The idea absolutely works but it’s a disaster for the coil Q.  To illustrate the problem I ran a quick experiment to illustrate the problem.  I’ve written a short note on the work which is posted at: www.antennasbyn6lf.com   In due course I’ll expanded this to give a detailed explanation of the phenomena and show a similar but not nearly as serious effect in variometers but this will have to do for right now.

  

GL and 73, Rudy n6LF

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