[TowerTalk] sharing radials

[Guy Olinger, K2AV]

You probably should have had the two connected all along. Since the tower is
parallel to the inverted L's vertical run, you must consider the tower
closely coupled. You will have been inducing current in the tower, and the
tower's ground rod will have been "sinking" the induced current.  (This
coupling is the principle in use in Force 12 and Bencher tribanders, where
there is no actual connection between two of the driven elements and the
feedline. The DE attached to the feedline couples the other two.) It does
not matter whether the tower is "resonant" or not.

If the RF resistance of the tower ground (including both the ground rod and
the base) is very low or very high, then it hasn't mattered much. But if the
resistance is in the 10-30 ohm range you may have been dissipating some
considerable power in the tower ground connection. This is likely the case
since ground rods are notoriously lossy connections at RF.

Hook them all together with broad copper strap.

If you were loosing a lot of power in the ground, you will see the tuning
settings change when you hook them together. If not, it probably won't make
any difference in performance.

Best o' luck.  Guy

From: <Dinsterdog@aol.com>
>
> Greetings- Another rookie question.....
>
> I have a 160 mtr Inv L that I have ran up 55 feet supported off the side
of
> my tower using 4 foot stand offs ....the top of the 60 foot tower supports
a
> 6 ele log periodic.....
>
> I have 90 1/4 wave radials at the bottom of the Inv L but I dont tie the
> ground radials to the tower-  the tower is grounded on it's own ground rod
> and the radials of the Inv L are grounded to a separate ground rod-
>
> I am thinking about putting up a 1/4 wave sloper off my tower- The antenna
is
> fed at the top of the tower...the feedline ground braid is clamped on the
> tower using a hose clamp at the top of the tower and the center conductor
is
> tied to the antenna- easy so far, eh?
>
> but in order to be effective- the 1/4 wave sloper it needs an extensive
> radial system- and the tower is suppose to tie into a good radial system
> below Ahhhhh!  The radial system of the Inv L looks good- so why not just
run
> a ground strap from the bottom of the tower to the Inv L's ground radial
> system centered a couple of feet away???.....
>
> Will this screw things up for the 160 meter Inv L????  after all, I am
adding
> a tower to the existing radial system.......Is it possible for two
different
> wire antennas, off the same tower, to use the same radial system????
>
> any responses would be appreciated-  73 Paul  N0AH
>
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>


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