Topband: Re: Grounded Half Loop Antenna

[David Sinclair]

ABowenN4OO wrote:
> N4OO:  W1FB also wrote about the antenna in his Antenna Notebook. It is 
> a partial repeat of the 82 QST article. The antenna is also covered in 
> ON4UN's Low Band Dxing, chapter 10. ON4UN provides an analysis of the 
> antenna and projects vertical and horizontal patterns. He does not 
> discuss harmonic operation.
> 
> I made one for 30M several years ago when the WARC allocations were new. 
> I used the top rail of a chain link fence as my counterpoise. The SWR at 
> the feed point was high, but I used a tuner to get a decent match. It 
> was a quiet antenna and I was surprised at the number of Europeans I was 
> able to work. I took the antenna down when I moved but have always 
> wanted to try the above version with a 50 ft vertical tower and 110 ft 
> slant wire to see how it plays on 80 and 40 over a ground system of 54 
> radials, 63 ft long. Maybe I will find time for that during the winter 
> months.
> 
> INK N4OO
> Sopchoppy, FL
> 
Thanks for the ON4UN Low Band DXing reference. John DeVoldere describes
the ungrounded version of this antenna as modeling 'high angle'. You
mention being surprised how well an grounded 30m version got into EU.
My own experience using an ungrounded half loop (80 half square)
on 160m was very positive. I understand that propagation from the US
east coast into EU is often surprisingly high angle. This may have been
what I was seeing with this antenna. My better, full size loop did at
times beat it into EU.

BTW I have been surprised how well my 80m 1/4 wave vertical wire,
working against about 55-60 ground radials, performs on 30m through
an antenna tuner. It is comparable with a relatively low (30-50ft),
partly sloping 30m dipole- often the same, sometimes slightly better
or slightly worse. The 80m wire does have a large, solenoidal choke
of RG-213 at the base of the antenna, FWIW.

73, David K3KY