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Re: [TowerTalk] four square array tuning

To: Peter Voelpel <dj7ww@t-online.de>
Subject: Re: [TowerTalk] four square array tuning
From: Steve Bookout <steve@nr4m.com>
Date: Mon, 28 Nov 2016 17:44:59 -0500
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Hello Peter,

I just don't remember it that way.  I guess I'm just getting old.

Another told me that I needed to remove the coaxes and short the box end of each coax.

I'll kick it's butt tomorrow.

73 de Steve, NR4M

On 11/28/2016 5:36:PM, Peter Voelpel wrote:
Hi Steve,

You need to OPEN the unused radiators while you adjust one at the time!

If connected to ground they couple to the radiator in tune.

73
Peter, DJ7WW

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Steve
Bookout
Sent: Montag, 28. November 2016 23:28
Cc: towertalk@contesting.com
Subject: [TowerTalk] four square array tuning

Hello all,

Over the last few years, I have added four square arrays for 40 meters
and 80 meters, and both work really outstanding.

Recently, I added a third one for 20 meters and am having a difficult
time with it.

Short version is I resonated each antenna individually, with the others
shorted with clip leads to gnd, to 13.9 MHz +/-.  The array, as a whole,
doesn't show a suitable SWR until 15.6 MHz! Like the others I had
installed, I was expecting a 150 KHz, or so, rise in frequency to
resonance.  I do understand that it's really all about the power being
dumped to the dummy load, but the amp is not going to tolerate a 3.5 to
1 SWR.

Cables were cut using an AIM antenna analyzer and were double checked.
All other cable/parts were checked out and shown to be correct.

80 ground mounted radials under each antenna.

Built just like I did the other two.

Gonna look at it with an O-scope tomorrow and check phase vs freq.  My
gut feeling is an incorrect value component.

My gut feeling aside, I would appreciate any ideas.

73 de Steve, NR4M

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