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[Towertalk] is an LP a good sloper top hat?

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Subject: [Towertalk] is an LP a good sloper top hat?
From: (Tom Rauch)
Date: Sat, 8 Jun 2002 06:50:18 -0400
> I have a tower mounted half-sloper, with an log periodic 
> on top of the tower. Problem is, the log is completely 
> insulated from the mast on the tower. Does it still work 
> as a top hat to the tower for the sloper to work against?

You can connect the log elements to the boom, so far as the slopper 
is concerned, without hurting the log. This assumes the log operates 
far above the frequency of the slopper, such as a 14-30 MHz log and 
an 80 meter slopper.

Wind a small push-pull (center tapped) coil out of #10 or 12 wire, 
and make it have several hundred ohms of reactance. Ground the center-
tap point to the mast, and connect each free end to each of the log 
booms (assuming that is what feeds the elements) where they pass the 

That will electrically ground the elements in the log to the mast for 
common-mode currents, and not upset the feed system for the log's 
differential currents.

By the way, NEVER tape or run the coaxial feedline along a boom in a 
log back to the tower, like some manufacturers advise as being OK. It 
messes up the balance in the log feed systems.73, Tom W8JI 

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