Joe, pick up a copy of March CQ magazine and p 50 has a nice article re your
problem. The simple truth is that most "tiny antennas" use the coax feedline
as the antenna. This may or may not be the intention of the designer. They
have either no balun or an ineffective balun so current from the coax inside
of the shield spills over and down the outer which radiates. This, of course
is an invitation to RF interference to stereos, phones, and such. The CQ
article describes using the rain trough system for an antenna to work over
100 countries from a good location.
I helped a blind ham friend in Dallas with a problem similar to yours. We
first threw a small rock with a piece of wire over his roof. After a bit a
roof maintenance guy tossed it back down. Then we attached a wire to the
downspout and loaded the rain trough system. That worked rather well and it
still does.
There is a place called Antennex which publishes lots of stuff on tiny
antennas. Many of the articles are authored by skilled scientists but, in
almost every case, the designs ignore the feed line radiation. This is very
difficult to minimize. K9YC has done excellent work in analyzing baluns and
has excellent designs on his web page using the latest and best type 31
ferrite. I am pretty sure that one of his great balun designs applied to
something like the isotron would show the true worth of the antenna.
A lot of guys use good quality mobile antennas with some radials or 2 as a
dipole to make effective antennas for tough situations. They either leave
them on their cars and run a coax into the house or just put them out at
night.
73, Dan, N5AR
----- Original Message -----
From: "WA6RKN" <WA6RKN@ARRL.net>
To: "Tower Talk" <towertalk@contesting.com>
Sent: Saturday, February 28, 2009 8:10 AM
Subject: [TowerTalk] Isotron Antennas
> If you gentle readers would bear with me while I take an excursion into
> some
> antenna type questions....
>
> Specifically, the Isotron Antenna.
>
> Being a skeptic, this antenna sounds too good to be true..
>
> So..I ask you folk..Opinions? Thoughts....good or bad.....
>
> (Or any suggestions of a small footprint antenna for use from an apartment
> landing. This one caught my attention as one could BS the apartment
> management and say it was a fancy sat dish. They wouldn't know the
> difference. LOL)
>
> Limited area for an HF antenna and severe restrictions necessitates the
> search and questions.
>
> Dipoles and other wire antennas are out. Verticals are pretty much out as
> well.
>
> Thanks in advance!
>
> Joe Wolfe
> WA6RKN
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
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