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[TowerTalk] ComTek - 80M 4-square advice

To: "'Tower and HF antenna construction topics.'" <>
Subject: [TowerTalk] ComTek - 80M 4-square advice
From: "N2TK, Tony" <>
Reply-to: "Tower and HF antenna construction topics." <>
Date: Wed, 21 Apr 2010 11:13:10 -0400
List-post: <">>
For several years my 80M 4-square has been working okay. It is 4 elevated
fed verticals. The verticals are sloped wires to the top of the tower. The
feedpoints are elevated because on the NW side of the tower I only have 35'
till I run into a stone wall. And there is no way of running radials on the
ground beyond the stone wall.

At each feedpoint there are 3 elevated radials 

The spacing of the verticals is for 3.650. The 70 ohm feedlines, cut for
3.650 have lots of ferrite beads near the feedpoint. The system is setup for
minimum dumped power into the dummy load at 3.775. I switch in a coil at the
feedpoint to the radials to bring the CW position to 3.520.

The ground in the area has lots of radials in the grass. Most are 100'
except on the NW side, which are as short as 35'.

I use a Comtek box to feed this.


I realize it is not the best setup but it has worked to a degree for several
years. I would get anywhere from 10-20db F/B depending on distance, and band


In February we had a bad snow storm that took down most of my wires.
Recently I rebuilt the 4-square to the same dimensions as before. Now there
is no pattern whatsoever. I have yet since rebuilding to see any sort of
pattern as I switch directions with the Comtek box.


Here is what I have done so far:

- Verified that the Comtek switch box is energizing the relays properly

- Removed one feedline at a time to see that it significantly increased the
dumped power.

- Checked the resonance of each vertical. They are all the same. 

- I shunt feed the tower on 160M. Nothing changed there. I use the MonstIR
on top to bring the tower into resonance for 160M. I moved the resonance of
the tower quite a bit with no noticeable change on 80M

- Verified that all of the elevated radials and vertical wires are very
close in length.


Is there any way to check the Comtek box? The ferrite cores and wires on
them seem to be fine. Anything else I should check? 

Maybe one of the relay contacts are bad but thought that would upset the
dumped power?

Am I missing something simple?

Any feedback and ideas are appreciated.



N2TK, Tony





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