John - set the Alternate Zo to the Rr of the antenna at resonance to get a
picture of what it would be if matched... somewhere around 36 ohms should
do.
g.
-----Original Message-----
From: john@kk9a.com
Sent: Tuesday, November 14, 2017 2:36 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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