Thanks Paul,
I've attached the Source Data output below. This, I believe, is showing me SWR
and impedance at the feedpoint of each element. I'm not sure if EZNEC gives me
a way to see the SWR at the single feedpoint that I'll use to feed these two
feedpoints but I assume it will be equally as bad.
I'm using the standard ARRL W8JK model that comes with the demo version of
EZNEC in the ARRL antenna book. I modify that model to look like what I want
to build and as long as I don't save it the software performs like the full
version of EZNEC. I'm over my head with antenna modeling as soon as I move
past modeling a dipole but I forge ahead and try and get as much useful
information as I can from it.
The question still is, if I get the antenna working properly how much loss will
I see on the feedline. Thanks much for your help.
EZNEC ARRL ver. 4.0
2/28/2012 7:53:59 AM
--------------- SOURCE DATA ---------------
Frequency = 7.05 MHz
Source 1 Voltage = 397.6 V. at -89.63 deg.
Current = 1 A. at 0.0 deg.
Impedance = 2.597 - J 397.6 ohms
Power = 2.597 watts
SWR (50 ohm system) > 100 (75 ohm system) > 100
Source 2 Voltage = 397.6 V. at 90.37 deg.
Current = 1 A. at 180.0 deg.
Impedance = 2.597 - J 397.6 ohms
Power = 2.597 watts
SWR (50 ohm system) > 100 (75 ohm system) > 100
Total applied power = 5.193 watts
Gary Slagel
KT0A
________________________________
From: Paul Christensen <w9ac@arrl.net>
To: Gary Slagel <gdslagel@yahoo.com>; TowerTalk <towertalk@contesting.com>
Sent: Monday, February 27, 2012 4:48 PM
Subject: Re: [TowerTalk] balanced line loss on a mismatched antenna
> "I think I can tune the antenna with the feedline and get it down to a more
> reasonable level, maybe 10 to 1, at the tuner end. Then the tuner will tune
> it to resonance so the xmttr can put its full load into.
> Question is, since the swr is 10 to 1 at the radio end of the feedline but
> 100 to 1 at the antenna end of the feedline, am I going to see the 3.5 db
> loss from a 100 to 1 swr or the .5 dbi that a 10 to 1 swr would give me."
Gary, you can vary the impedance at the input end of the line, but not the
SWR. The SWR on the 450-ohm section will remain nearly constant over your 150
ft run, even with length trimming.
In EZNEC, what is the Z of the antenna you're modeling at the operating
frequency in an R+j format?
Paul, W9AC
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