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@kk9a.com
Sent: Tuesday, November 14, 2017 1:36 PM
To: towertalk@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@contesting.com
Subject: Re: [TowerTalk] 4 square advice
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Sun, 12 Nov 2017 10:25:13 -0800
On 11/12/2017 7:35 AM, john@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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