[TowerTalk] 4 square advice

[Jeff]

But you are talking about a 4-square and not a vertical.  So this experiment 
shows that a vertical with a fatter element is more broadbanded and that 
certainly implies the same with a 4-square, but it does not in a practical 
sense convey the specific benefit of using a wider element in the common 
case of a 4-square with a conventional hybrid combiner.  What I wanted to 
know was the return on my investment hassle to use the dual wires.  AutoEZ 
provides me that answer which is why I point it out.

The author has cooked up a hybrid as part of the 4-sq model and that means 
you I can look specifically at the dump power % coming off the combiner over 
my bandwidth of interest as I vary the element sizes.  My plan is to build 
up the array with a single wire for start and measure the dump power and 
then move to the 2 wire to test the model prediction.

Good luck

73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

-----Original Message----- 
From: john at kk9a.com
Sent: Tuesday, November 14, 2017 1:36 PM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] 4 square advice

AutoEZ appears to be a valuable tool. I am not designing anything new
lately but I'll still probably purchase it when I have some time to play.

To compare the 80m SWR bandwidth of different tubing sizes I used a simple
vertical model over average ground with no matching (resonant SWR~1.38).

2.00 tubing - 3.5MHz 1.87:1  3.8MHz 1.87:1
0.09 tubing - 3.5MHz 2.38:1  3.8MHz 2.38:1

John KK9A

To: towertalk at contesting.com
Subject: Re: [TowerTalk] 4 square advice
From: Jim Brown <jim at audiosystemsgroup.com>
Reply-to: jim at audiosystemsgroup.com
Date: Sun, 12 Nov 2017 10:25:13 -0800


On 11/12/2017 7:35 AM, john at kk9a.com wrote:
You don't need AutoEZ to see the effect, EZNEC will work.

Right. But AutoEZ allows us to do a LOT more calculations a LOT faster.
If you own Excel, AutoEZ is well worth the $75 cost.

I just ran a model
of a single vertical using 2.00" tubing and one with .090" tubing.  The
bandwidth difference was more different than I would have guessed.

What was that difference, John?

73, Jim K9YC

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