[TowerTalk] Fwd: Fwd: Fwd: OCFD

[Hans Hammarquist]

 Good point, Rick,

Hans - N2JFS

 

 

-----Original Message-----
From: Richard (Rick) Karlquist <richard at karlquist.com>
To: jimlux <jimlux at earthlink.net>; towertalk <towertalk at contesting.com>
Sent: Tue, 28 Mar 2017 22:19
Subject: Re: [TowerTalk] Fwd: Fwd: OCFD



On 3/28/2017 2:54 PM, jimlux wrote:

> because it's not "really" an end effect or capacitance. The actual
> phenomenon is that  X goes through zero at a frequency where the dipole
> is not exactly a half wavelength long.  There's a lot of ways you can
> analyze around it or conceptualize it, but they're just mental models.
>
>
> Another way to think about it is that the propagation velocity down the
> wire is not c, but slightly slower (because the wire has inductance and
> free space capacitance, and you can calculate the prop velocity as
> sqrt(L/C))
>

The trouble with this description is that it doesn't explain why the
third harmonic resonance of a dipole is greater that 3X the fundamental
(half wave) resonance.  OTOH, the "end capacitance" concept neatly
explains it.  Three times as much wire, but no additional end effects.

73
Rick N6RK
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