Re: Subject: Reality. Re: Medhurst self resonant frequency and nodality (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 19 Oct 2007 12:17:06 -0400
From: Dave Pierson <davep@xxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Subject: Reality. Re: Medhurst self resonant frequency and
    nodality (fwd)


>Subject: Subject: Reality. Re: Medhurst self resonant frequency and nodality
>    (fwd)
>
>Subject: Reality.   Re: Medhurst self resonant frequency and nodality (fwd)
>
>
>>This not only applies to an inductor but to a straight wire as well. In
>both
>>instances the results will be closest to ideal when the solenoid (or wire)
>>is long and many nodes are present.
> .....
>
>>The self resonant frequency of Wavelength/2 for a wire is solely a function
>>of its length.
> Except.
> The winding of wire into solenoid changes the self resonant frequency.
> cf any good text on antenna engineering.
>
> Or a good ham radio book, under 'continuosuly loaded antennas'.
>
> Roughly: for long, skinny, closely wound antennas, ONE HALF wave
> of physical wire length 'looks like' 1/4 wave of straight wire.
> This is the measured reality.
> (To the extent that such arrangements are not commonly used as
>  antennas, may need to dig a bit for the refrences.  Still: true.)
>
> as the 'form factor' changes: becomes shorter/fatter, the physical
> length and the electrical length become closer.
>
>> Thus a given wire will have the same resonant frequency
>>whether it is straight or wound in a solenoid. This stands to reason since
>>node spacing is entirely a function of wavelength, or in our case, wire
>>length.
>  cf as above.
>
>  Try the measurement.
>
>  best
>   dwp
>?????????????????????????????????????????..
>Greetetings dwp:

>Take a look at the G3YNH web site  under inductors and transformers part 3
>page 3.
    Take a look at real antennas, built as solenoids, with real wire.
    Formulas are nice.
    There is also the real world.
    Or the refeerences provided.

     best
      dwp