I have the same experience .. a number of short radials and a few long ones,
but only in a 180 degree pattern because of the lot lines and an ill tempered
neighbor. I have several tower sections unused and placed them at base of
vertical, bonded all together and hit a few ground rods per section to bond
them too. That made a significant improvement.
If you recall in the old Stew Perry literature his description of an Inverted L
included burying all sorts of heavy metal at base in addition to whatever you
can arrange for radials.
Sent from my iPad
On May 17, 2011, at 11:17, "ZR" <zr@jeremy.mv.com> wrote:
> Before I knew better, 30+ years ago, I had a 90' tower with 10-20 yagis
> shunt fed on 160. It was about 40' from the road on the NE thru SW side so
> many radials were very short and others ranged up to 120' long. The ground
> was poor, consisting of deep sand with just a thin layer of topsoil.
>
> It worked fair but not well considering I was running 1200W. Most DX
> contacts required waiting in a long line.
>
> Then I realized about current being maximum starting from the base and I got
> a bright idea. At the local garden center I picked up 5 rolls of "rabbit
> fence" which were 2 x 4" welded and galvanized wire mesh coated in green
> plastic and were 50 x 4'. I laid these down in a spoke, stripped back some
> plastic, and soldered the ends to the ground ring at the tower with #12
> copper wire. I also connected them together at the far end of the overlaps
> with another ring.
>
> After retuning the match that antenna kicked butt.
>
> After a bit of grass seed and fertilizer it was completely out of the way of
> the lawn tractor in a few months.
>
> Carl
> KM1H
>
>
>
> ----- Original Message -----
> From: "Cormac Gebruers" <ei4hq.mail@gmail.com>
> To: <topband@contesting.com>
> Sent: Monday, May 16, 2011 1:20 PM
> Subject: Topband: Asymmetric radials for GP antennas; Just in case others
> seek what I've just found...
>
>
>> All,
>>
>> I've been searching for clarity and hard data on the effects of asymmetric
>> radials on radiation patterns and efficiency of a vertical as I'm
>> installing
>> a 21m vertical for 80/160 and will have to live with a radial system that
>> is
>> significantly compromised over a 180 degree sector.
>>
>> I was a bit surprised to "not find" this subject dealt with in any clear
>> decisive way in e.g. the ARRL Antenna Book or ON4UN's otherwise excellent
>> Low Band DXing book (Did I miss it in either publication? If so, just send
>> me a "your an idiot" email and I'll crawl back under my cabbage leaf
>> suitably chastened).
>>
>> I was surprised as I had always assumed it is something many hams have to
>> deal with unless they are prepared to go on "stealth missions" in the dead
>> of night to lay radials on or under neighbours property (I don't recommend
>> this course of action by the way; I attempted just such a thing once and
>> got
>> caught. As a mental exercise to occupy you during those quite times when
>> calling CQ on a dead 160m, try explaining your way out of that one).
>>
>> On the basis that there might be one/some/many out there, who, like
>> myself,
>> are installing verticals with radial systems that are compromised
>> directionally as well as "length-ways", I just thought I'd share what I
>> found; N6LF's excellent (if not exactly encouraging) summary of the
>> consequences of asymmetrical radials at
>> http://rudys.typepad.com/files/qex-ground-systems-part-7.pdf . It's well
>> worth the read.
>>
>> I hope to hear you all on the far side of the Summer...
>>
>> --
>> Regards
>> Cormac (EI4HQ)
>> [Cork/UTC+1] NNNN++++
>> http://86.43.106.118/ei4hq/
>> http://www.corkharbourweather.ie
>> _______________________________________________
>> UR RST IS ... ... ..9 QSB QSB - hw? BK
>>
>>
>> -----
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>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
_______________________________________________
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