[TowerTalk] 4 square advice

[StellarCAT]

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 at kk9a.com
Sent: Tuesday, November 14, 2017 2:36 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