Jack Belrose, VE2CV, wrote:
> In one, Roger Jennison, G2AJV (see Radio Communications (RSGB magazine),
> April, May and August, 1994) described his toroidal antenna as follows.
> ...
> I would be pleased to receive views on these new "revolutionary" toroidal
> antennas. Correspondence concerning performance of toroidal antennas has
> ranged from skeptical to beyond belief!!
Allen Davidson responds,
> It basically says you can make it physically as small as you wish (within
> the constraints of tolerances), and you can get large gain, but you will
> have diminishingly small bandwidth....
>
> So, if it looks too good to be true, it probably is. And this paper should
> allow one, who has the time to spend, to quantify how much too good it is.
Jack's posting tickled a memory cell, so I went home and dug up an issue of
Communications Quarterly. Sure enough... in the Summer 1995 issue of the
Comm Quarterly (ISSN 1053-9344), there is an article by Roger Jennison, G2AJV,
titled "The G2AJV Antenna, And Maxwell's displacement current." U.S. residents
may find the Comm Quarterly easier to get hold of than the RSGB publication.
Same publisher and address as another amateur radio publication, "CQ Magazine."
One of the "practical" antennas described by Jennison is a toroidal antenna
that is 30 inches wide, held between two metal plates, from what I can gather
from the drawing, also 30 inches in diameter. The plates are said to be
separated by a mere 7 1/2 inches!
Bandwidth on the 160m band is said to be "15 Kc/s" (Jennison is an Emeritus
Prof. :-).
This supports what Allen Davidson posted.
73
Kok Chen, AA6TY kchen_at_apple.com
Apple Computer, Inc.
Received on Fri Nov 10 1995 - 22:27:00 EST
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