[TowerTalk] Raised radial question

[larryj@teleport.com]

Re: Item # 3: 

I have been using Butternut HF6V vertical antennas for many years. They
have gotten me 5BDXCC, about 260+ countries on 40-Meters and nearly 200 on
80 Meters. I've always had the antennas up on a roof, no more than about
15-20 feet above the ground, with about a half-dozen radials for various
bands - usually one or two for 80M, one for 30M, and 3 or 4 for 40-Meters
and up (like the Butternut multiband STR kit). I have never gotten around
to installing a ground wire from the base of the antenna to a ground rod.

I wanted to try elevating this HF6V at my new home up on a tall tower, like
in the ARRL Antenna Compendium, vol. # 2, pp.46-49 article, by K4IQJ. I
notice that the author doesn't appear to have the common point for the set
of radials isolated from ground - the base of the antenna, the ground side
of the coil which is across the coax feedline hot side to ground, and all
radials actually hook to the top of the 50 foot tower that the author is
using for a support. 

Are you suggesting that if I try an elevated multiband vertical up on a 60
to 70 foot tower, as in this ARRL article, that the radials should be
connected to ONLY the ground side of the coax feedline, and not also to the
support tower/mast or a wire to a ground rod?

Thanks and 73,

Larry


Original Message:
-----------------
From: Tom Rauch w8ji at contesting.com
Date: Tue, 15 Nov 2005 02:42:09 -0500
To: n3nd at aol.com, towertalk at contesting.com
Subject: Re: [TowerTalk] Raised radial question


> ground (then horizontal), have I gained anything?  Will a
few (3 or 4)
> elevated radials like mentioned be better than many ground
radials?
>

1.) If you only have a few radials, they generally work much
better elevated than laying on the ground.

2.) A large radial system (like 50 or so radials) is nearly
100% efficient, It is impossible to beat 100%.

3.) When you use elevated radials, any path to earth (like
the tower base being in the mud) will reduce efficiency.

4.) With only four elevated radials a few feet above earth
on low bands, the system will be a few dB to several dB
weaker than 50 or so radials laying on the ground.

5.) There is no free lunch.

73 Tom

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