I've been a ham for more than 50 years. Loops were around long before I came
around. Whether they were continuous loops or separated/opened by an
insulator they are all loops.
73
MAL
N7MAL
BULLHEAD CITY, AZ
http://www.n7mal.com
Everyone in the world is
entitled to be burdened
by my opinion
----- Original Message -----
From: Jim Lee
To: Tower and HF antenna construction topics.
Sent: Thursday, February 04, 2010 4:01
Subject: Re: [TowerTalk] Feeding a Delta Loop
Must be some QRM on this message exchange ! You
specifically mentioned that the bottom leg of your
Delta Loop was SEPARATED with an insulator -- i.e.
the loop was not continuous. What am I missing
here ?
73
K5KKV
----- Original Message -----
From: "Kenneth R. Goodwin, Jr."
<krgoodwin@comcast.net>
To: <towertalk@contesting.com>
Sent: Wednesday, February 03, 2010 9:25 PM
Subject: Re: [TowerTalk] Feeding a Delta Loop
>
> I went for horizontal polarization with the feed
> point at the apex at
> the top of the 80 foot tower. I used a
> quarter-wavelength RG-11 line
> as an impedance match for the 100 ohm antenna
> feed impedance to 52
> ohm RG-8 coax to the station. My baseline
> reference is the W1FB and
> W1SE article in the October 1984 issue of QST
> (page 24) which details
> all possible configurations. When I lost a few
> of my pine trees that
> support the base leg to pine bark beetles this
> past summer, I had to
> move the end supports. I was surprised as to the
> sensitivity of the
> SWR to lengths of the three legs. Not having
> all three legs
> reasonably equal caused a significant difference
> in the SWR. Guess I
> was lucky the first time I put it up 20 years
> ago so on the new
> configuration I constrained the insulator
> connections to the base leg
> with wire rope clips. Over the years, I've
> ended up preferring
> insulated wire over bare copper wire - just
> lasts much longer in the
> high humidity environment. For K5KKV's benefit,
> the overall length
> of the delta loop is 1005 divided by f in MHz
> which makes it a full
> wavelength. For 80 meters that would three legs
> around 95 feet each
> or a total of 285 feet/86 meters. Ken K5RG
>
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