Topband
[Top] [All Lists]

Re: Topband: full wave loop

To: "Mark Lunday" <mlunday@nc.rr.com>, <topband@contesting.com>
Subject: Re: Topband: full wave loop
From: "Tom Rauch" <w8ji@contesting.com>
Reply-to: Tom Rauch <w8ji@contesting.com>
Date: Thu, 3 Mar 2005 05:57:06 -0500
List-post: <mailto:topband@contesting.com>
> I'm a new op to 160, but I can tell you that it is
supposed to work at that
> height (50') with resulting lower angles of radiation.
EZNEC simulation
> tends to support that idea.  ARRL antenna book has some
more details on the
> "sky loop," which is a full wave in size.

Mark,

I disagree.

A horizontal full-wave loop focuses the signal upwards at
high angles, and cancels any radiation along the horizon.
Just like a low dipole, it is a cloud warmer.

The full wave loop has almost no gain and almost no
electrical advantage for single band use. The reason is
quite simple. The loop tends to NULL the signal along the
horizon, but the earth itself already nulls the horizontally
polarized wave along the horizon. The result is the loop
forces a null where a null already exists, and this prevents
it from modifying the pattern substantially from that of a
dipole. When the pattern is the same, the performance is the
same.

You'd really never see the difference between a low
horizontal loop and a low dipole, except for sheer luck
making one randomly better than the other depending on
near-field coupling to things around and under the antennas.
With random luck a dipole might be better or a loop might be
better, but in the big picture they are essentially equal.

73 Tom




_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband

<Prev in Thread] Current Thread [Next in Thread>