If you use a good feedline, there is little loss from higher SWR at the band
edges. For example if you use 100 feet of Belden RG-213 at 3.8 Mhz and the
antenna has a whopping 4:1 SWR ratio, the additional coax loss is less than
0.4dB. Of course having an antenna with a low SWR across the band, like the
80m cage dipole, will make your radio happy. There are also other methods
of making the SWR appear lower with a conventional dipole by adding 1/4 wl
of 75 ohm coax at a specific location in your feedline.
John KK9A
To: <TOWERTALK@contesting.com>
Subject: Re: [TowerTalk] Cage dipole gain figures
From: Gary Bonnor <jamieb@optusnet.com.au>
Date: Wed, 15 Apr 2009 18:10:50 +1000
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Hi All,
I don't think you lot are thinking far enough outside the square !!!
What is the gain of the cage dipole at its 2:1 VSWR points over a
single wire or element dipole at the same frequency points ??
This is probably where the 5dBd comes into the equation.
Catchya,
Gary
VK4ZGB
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