[TowerTalk] Half slopers using a tower

n4kg@juno.com n4kg@juno.com
Wed, 2 Jan 2002 07:47:17 -0600


On Tue, 1 Jan 2002  hasan schiers <schiers@netins.net> writes:
>
	SNIP 
>
> I've used the w9inn 160/80/40 sloper on a 72' tower with hf antennas 
> above as  a capacitive top load. On 160 the vast majority of the
current 
> was  in the  tower. On 80, the tower still dominated, on 40 the wire
portion 
> started to  share the current distribution more equally.

	Interesting observation Hasan.  Another SIMPLE
	solution is my elevated GP trick, placing insulated
	1/4 WL radials at 10 to 15 ft above ground, just like
	a sloper, but horizontal and low on the tower.  The
	length of the radials can be adjusted for resonance.

	It helps to have an antenna analyzer, preferably one
	that will show both resistance and reactance, for
	tuning / matching.  SEVERAL people have told me
	they have used this technique successfully with 
	as few as two radials.  Of course more is better.

	I insulate the radials with nylon cord loops and
	connect the wires directly to the center conductor
	of the feedline.   Tom  N4KG

> I would model your situation wit EZnec and see what is 
> really going  on. 

	There's nothing like a good model !   N4KG
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