[TowerTalk] "Half-Loop" Antenna?

[David L. Thompson]

At 03:51 AM 6/16/98 +0000, Brian Short k7on@qsl.net wrote:
>
>The Antenna Compendium describes some experiments 
>with the "Half-Loop" antenna which is a half of a full loop 
>antenna fed against a ground screen.
>
>It would be fed at the ground, then go up to a support, and 
>finally back down to the ground again, sorta like an inverted 
>V dipole, but fed at one end against ground rather than at 
>the center.
SNIP
>I am curious if anyone has experience with this type of antenna?
>

There have been many write ups by Belrose and others on the half loop.  The
best example of the half loop was set up by Dave (Loop Skywire) now NC7W
at K4TEA.  I put a short write up on the antenna in the 4th edition of the
Amateur Radio Mail Order Catalog and Resource Directory under practical 160
antennas.

The basic antenna is 65 feet up, 130 feet across as a flat top, and 65 feet
down.  Feed at either end with coax.  At each end put down a ground rod and
as many ground radials as possible (K4TEA's has 120 at each end).  Then
(this is key) run a tie back line between the two grounds.  The antenna is
nearly omni (oval with slight directivity end fire the feed point.)  Ken
K4TEA has 238 countries at last count so it works well.  Belrose talked
about the half loop off a tower (even using the tower).  However I feel its
best independent of a tower...certainly easier to tune.  One hint...don't
run it over your house or even near the tower (except at one end)..K4UEE and
I tried it and it may work great one direction but the house killed the
antenna toward Eu...but JA and YB called me.  K4TEA's is between two large
pine trees away from house and tower.  Another local did let his tower hold
one end (10' away) and did OK.

73, Dave K4JRB


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