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
|
