[TowerTalk] 40 -2cd

[alsopb]

Hi Marc,

Others looking at the same data concluded that your antenna is working
properly at 28 M. I'm not so sure.  One has to have some reasonable
explanation of why the minimum SWR changed so much (1:1 to 1:1.5 over
the 4 meters).

I looked in the antenna handbook which shows how the impedance of a
dipole varies with height above ground.  At 24m it shows an impedance
of about 58 ohms.  At 28 meters it shows an impedance of 68 ohms. 
Thus the impedance of your antenna (if it were a full sized dipole)
would increase about 10 ohms.  The direction is right.  Ten ohms
represents about 0.2 in SWR. You are seeing more than twice this
magnitude. 

If this is "normal", I'd like to know what other physical effects are
doing it.  It might have something to do with the
shortened/loaded/beam configuration.  Anybody out there know?
 
73 de Brian/K3KO


Marc Wullaert wrote:
>

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