Re: NEC-LIST: cross field antennas

In a message dated 2/10/99 2:59:01 AM Eastern Standard Time, rwa_at_ibm.net
writes:

<< A group of SRI engineers assembled a "kit" obtained from the
inventors (for 400 pounds sterling) and tested it under very carefully
controlled conditions. They used a very good ground plane (no loss)
and hardline coax to prevent leakage radiation and loss-induced feed
point resistance terms and removed the phasing networks from the
vicinity of the antenna to prevent currents from the antenna from
flowing on the outer conductors of the cables. Results: A very short
antenna with typical highly reactive input reactance and very low
resistance and no surprises in field strength measured. (These
results are not available as they were funded by an agency that
remains very low profile.) >>

Thanks R W for filling us in. It is a pity that this isn't published
though. But one can think of several low profile agencies that--if
the thing worked--might need to keep the info unpublished. The fact
that it didn't should have made it easier to get publishing
clearance. But then who on the team wants to waste time writing it up?

I must confess (perhaps yet again) that I have had similar experiences
with the contrawound toroidal helix antenna (CTHA). When the radius of
the toroid is less than about 1/8 wave, I can't get it resonant
(without external loading); the field strength is poor; and I just
don't get it. Period. Perhaps others have tested it since I did 3
years ago. I note there was supposed to be a modeling talk (it was
scheduled at) ACES in 1996 but it didn't materialize.

73
Chip N1IR
Received on Wed Feb 10 1999 - 12:15:02 EST