Topband: Inverted L

[Guy Olinger K2AV]

If you pull up an inverted L next to a tower, be sure that the base of
the tower is bonded to the ground radial system.

Depending on all kinds of things, the tower can carry anywhere from
next to no current, to actually carrying more current than the L.

Your setup appears to be 75 for the tower, say 3 for the mast
(guessing), plus 12 for half the boom, plus 17 for half a 20 meter
element. That is 107 feet, not so far off 125 and will carry current.
A feedline with the shield connected to one side of a tribander driven
element that comes away from the base of the tower without being
grounded can carry as much current on the shield as on the L,
regardless of whether there is a balun, since it will be so close to
the high voltage, no current part of the conductors on 160m.

There is also the question of what the horizontal part of the L does
to the pattern of your tribander directly underneath.

You may do better by gamma-matching the tower if the only possible
support for the L is your tower. Matched towers with a dense radial
field underneath have done very well.

Do you have any 80', 100' trees on your property?

73, Guy.

On Thu, Feb 11, 2010 at 1:48 PM, John Clark <n5er74 at yahoo.com> wrote:
> Looking to build an inverted L can anyone point me toward a good set of plans. Or plans for something that will work
> have way decent.
>
> I plan on hanging it on my tower.
>
> A 75' Rohn 25 with a Force 12 C-3 on top I have 3 acres of land to work with for radials and the like.
>
> Thanks
> John N5ER
>
>
>
>
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