>The velocity factor in the coax is the same on all bands (of course), but
>the amount of phase shift between the two antennas will be different on
>different bands if unequal line lengths are used. The horizontal offset
>between the two antennas can only be compensated for on one band with this
If the phase length of the free space horizontal offset (FSHO) is xdeg
on 20 then it is 21/14 * xdeg (or 3/2 * xdeg ) on 15, and 28/14 * x
(or 2 * xdeg) on 28.
If the coax is .66 VF, then the length of coax offset to match is 2/3
FSHO. 2/3 * 1/VF = xdeg on 20, 3/2 * xdeg on 15, and 2 * xdeg on 10.
The phase shift varies by band, BOTH in the physical offset, AND in
the coax. They vary in like amounts.
This DOES assume that you are NOT using 72 ohm odd quarter wavelength
matching devices, but a stackmatch kind of solution, that can accept
varying distances to the load.
> From: Guy Olinger, K2AV [SMTP:email@example.com]
> Sent: Thursday, December 16, 1999 8:31 AM
> To: firstname.lastname@example.org
> Subject: Re: [TowerTalk] Re: The Ultimate One Tower System
> On Thu, 16 Dec 1999 10:06:00 -0500, you wrote:
> >At 09:03 AM 12/16/1999 -0800, Jay Terleski wrote:
> >>The offsets can be compensated for easily with a little longer
> >>calbe that acts as a delay line to electrically aliegn the driven
> >>elements, when pointed in the same direction.
> >>Its already been done.
> >On 3 bands with the same length of coax?
> Sure, you are compensating for a distance in the open with a piece
> coax with that has the same velocity factor on the bands in
> It does assume that you are not using 1/4 wave matching sections and
> the like, eg using a stackmatch type of matching.
> >73, Pete N4ZR
> >Don't forget to update your entry in the contest station database
> --. .-..
> 73, Guy
> Guy Olinger, K2AV
> Apex, NC, USA
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Guy Olinger, K2AV
Apex, NC, USA
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