In article ,
Jeff Liebermann wrote:
On Tue, 25 Apr 2017 22:38:56 -0700, Jeff Liebermann
wrote:

Sheesh. I'm an idiot. I just noticed that I already have a model of
an alternating coax collinear on my own web pile:
http://802.11junk.com/jeffl/antennas/CoaxVert/index.html

I fixed a few things, made some better images, and renamed the folder:
http://www.11junk.com/jeffl/antennas/CoaxVertical/index.html

Looks like the 1/4 wave section at the top is missing. I'll fix it
tomorrow. It's late, I'm tired, etc...

Thanks! I'll pull down this model, read through it so I understand
it, and run a few sims myself.

On Wed, 26 Apr 2017 11:23:23 -0700, (Dave
Platt) wrote:

In article ,
Jeff Liebermann wrote:
On Tue, 25 Apr 2017 22:38:56 -0700, Jeff Liebermann
wrote:

Sheesh. I'm an idiot. I just noticed that I already have a model of
an alternating coax collinear on my own web pile:
http://802.11junk.com/jeffl/antennas/CoaxVert/index.html

I fixed a few things, made some better images, and renamed the folder:
http://www.11junk.com/jeffl/antennas/CoaxVertical/index.html

Looks like the 1/4 wave section at the top is missing. I'll fix it
tomorrow. It's late, I'm tired, etc...

Thanks! I'll pull down this model, read through it so I understand
it, and run a few sims myself.

Great. Maybe you can explain it to me.

Here's a rec.radio.amateur.antenna 24 article thread on the topic from
Nov 2008:
https://groups.google.com/forum/#!msg/rec.radio.amateur.antenna/DREJnRznluQ/58Z0gIimqdwJ

This is where I totally blew it when I incorrectly declared that most
of the RF comes out of lowest element, and very little out the top.
https://groups.google.com/d/msg/rec.radio.amateur.antenna/DREJnRznluQ/bZyCgwa0JvwJ
That was like saying that in a series string of identical light bulbs,
the lowest lights would be brighter. Argh.

Corrections and comments by Roy Lewallen (W7EL) including the original
model of the alternating coax vertical antenna:
https://groups.google.com/d/msg/rec.radio.amateur.antenna/DREJnRznluQ/LOwnb-eZmjMJ
I converted it to 4NEC2 format. See:
http://eznec.com/misc/rraa/
for original model in EZNEC format. This model does NOT run in the
Demo version of EZNEC 5.0 because it contains 80 segments and the demo
program only allows 20.
https://www.eznec.com

Good luck.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558