When I was technical editor at the RSGB in 1994 an interesting article
was received from Prof Jennison G2AJV on a toroidal antenna. Before
publishing it I felt that I should make one. This turned out to be a
problem but after several phone calls with G2AJV a 14MHz version using
two toroid coils and no end plates was made to work
The article was published in RadCom April/May 1994 'The G2AJV Toroidal
Antenna'.
After the article was published I continued to experiment with this
antenna. I also met Prof James Corum, K1AON at Dayton, who passed on
additional information on this antenna - he has a patent on the toroid
antenna.
Eventually my 14MHz version performed as well as a 14MHz loaded whip
antenna and the whole saga was written up in RadCom August 1994
'Evaluation of the G2AJV toroid antenna'.
All these RadCom articles are well illustrated with colour photos.
Regards
Peter, G3LDO
On 01/03/2010 19:56, Graham wrote:
Making a Torodial antenna, as presented at the Egham HFC would
be a good start .. the concept of the mirror differed from the
published articles ... I made one and oddly it worked quite well
at Hf ..how it worked ive no idea .how a 12 inch diameter coil
resting on a old no-entry sign (alloy plate) one end fed with coax
from the atu the other open achived qso's from 160 to 10 mtrs ..
who knows .... .its still hanging in the shed .. but a large one
may work at 9 khz without the need for all the coils etc ...
Did anyone else attend the lecture ?.. it followed the chap from
Birmingham with a selection of loop antennas . ....
G ...
NB .. Can anyone read this .. as '' design of toroidal reflector
..... Antennas '' is showing in the google search
http://www.informaworld.com/smpp/content~content=a770413350&db=all
--------------------------------------------------
From: "Alexander S. Yurkov" <[email protected]>
Sent: Monday, March 01, 2010 1:59 AM
To: <[email protected]>
Subject: LF: 9kHz without high voltage
I was wonder if it is posible to use a loop on 9 kHz. Serious problem
to radiate 9 kHz is high voltage we saw. Loop has that advantage that
voltage is not too high. Then i do some estimations. Let's assume
vertical
loop 15m x 50 m with 20 mm diameter coper tube as a wire. Then
effectivity
of such a loop on 9 kHz is about -65 dB. It is adequate to radiate 1 mW
on 9kHz (I=250A, TX power about 4 kW). We saw such a radiation should
give abt 100 km distance in QRSS. Besides such a loop is wellsuited
for 136 kHz. On 136 kHz it effectivity should be about -25 dB. Not too
bad: 1 W radiation with 400 W TX :-)
Regards,
Alexander
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