Jim,
Thank you, I may add some longer radials. There certainly is much
confusion and conflicting information abounding when it comes to radials.
In some cases this may be due to inadequate care taken in the writing of
guidelines. Maybe I should note this latter point myself.
73 Doug EI2CN
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Jim
Thomson
Sent: 01 March 2016 02:28
To: towertalk@contesting.com
Subject: [TowerTalk] Radial question
Date: Mon, 29 Feb 2016 20:26:35 -0000
From: "Doug Turnbull" <turnbull@net1.ie>
To: "'Larry Banks'" <larryb.w1dyj@verizon.net>,
<towertalk@contesting.com>
Subject: Re: [TowerTalk] Radial question
Larry,OMs and YLs,
Your point is correct some of the antenna books are very vague on this
point but I have seen it reinforced on the Top Band Reflector. Generally
Qty 120 one hundred ten foot radials would be more than adequate for full
performance and of course 110 feet is less that a even 0.25 wavelength on
160 meters let alone 0.4 wavelength.
I am always learning and am open to correction but this is an issue of
some importance to me so I have read a fair bit and follow all discussions
on the topic.
I am glad to hear others emphasizing that when using as few as sixteen
radials that the sensible length is 0.1 wavelength and I again would be
pretty sure the actual wire length is shorter due to the ground changing the
velocity factor for the wire.
Now again I am open to correction and I am still learning. Modelling
is for sure a good idea but you will need to know your soil characteristics
and conductivity and have a program which takes this into consideration
unless I am very much mistaken.
This is an interesting subject and as I say there is much to learn.
73 Doug EI2CN
### Forget the top band reflector. If you are using 110 ft long radials,
then 120
of em is a waste of effort. The distance between the far ends of adjacent
radials are
way too close together. The optimum number of radials....if 110 ft long
radials are used,
will be way less than 120 of em.
## If you hell bent to use 120 radials, they would have to be longer than
110 ft to be effective.
If you are using a 4 square, with 1/4 wave spacing, then you can only
achieve 1/4 radials between
each vertical, in the direct line route. Some of the remaining radials
will overlap of course, and
some will be full length.
## Too bad somebody couldn't install 120 x .4 wavelength radials....then
do some exhaustive tests,
like precise field strength measurements, both in the near and far field,
and also on 100-10,000 mile paths.
Then chop the radials down from .4 wave....down to .25 wave, toss the
chopped wire into the scrap
bin, then re-do all the tests again. Then compare the longer and
shorter radial tests.... with software.
Then see how they compare.
## then repeat the entire rigmarole...on lousy soil.
## If you have the room for long radials, wire is relatively cheap, and
can be added as time and expenses allow.
## the 3 x local AM broadcast stations locally, are all on small islands
offshore. And all of em use 10/8 ga wire radials, bare,solid
CU, and all of em go right into the saltwater...even at low tide. One of
them, (now shut down) used a 4 x tower array, with all 4 x towers
inline, oriented N-S. The array radiates W. Our town is W of the
array. The signal is (was) a rock crusher. A buddy on a cargo ship,
off the coast of Japan told me, he could easily hear it after dark each
night. And JA is 30 degs off of due West.
Jim VE7RF
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