Re: NEC-LIST: cross field antennas

Dear OM,

You wrote:

> The physical shape of the antenna is very similiar to the original
> CFA however one crucial ( in hindsight ) essential physical element
> has been added. ( it simplifies the not only the mechanical
> structure but also the matching ... and no Virginia it is not a
> loop.)

> I am not sure I should reveal the structural variation to the
> original CFA as I have been urged to take out a patent.

Perhaps Hatley has something up *his* sleeve also.

> The matching circuit reduces now to a 50:377 broadband transformer
> ie the feedpoint of the antenna is close to 377 ohms. Current and
> voltage maxima at points on the antenna structure are extreme. ( at
> one point if a piece of pvc tape is stuck to the antenna structure
> I can hear the 'noise' (in a receiver ) it generates when it is
> peeled off - it also gives a distinctly painful 'burn' if touched
> at powers of even 1 - 2 watts )

The Egyptian MF station operated at a power of 60 kW!!! The high near
fields would be expected (providing you are successful in having all
the power going forward). Clearly the CFA will couple into
everything. That was my point --- I wondered about the proximity of
the resonant quarter wave vertical nearby.

Do you have wire antennas nearby? All amateurs do. To be absolutely
sure that your radiator is the CFA you should do the tests in an open
field.

A 50:400 ohm transformer is relatively easy to wind, using ferrite
toroids --- but broadband transformers only work well if the antenna
system is approximately resonant.

If you want to join the crowd of enthusiastic believers read Jack
Stone's antenneX On Line Magazine:

Jack L. Stone, Publisher
antenneX Online Magazine
c/o Texas Capital Management
P.O. Box 72022
Corpus Christi, TX 78472

E-Mail: jack_at_antennex.com
Voice: 512.855.0250
Fax: 512.851.8278

There are five articles on the CFA posted there. I am not a promoter
of this magazine. I only heard about it as a result of recent
posting. I have not read these articles, but I have looked at the
authors of the CFA article --- one of them is Maurice Hately, GM3HAT,
himself.

73, Jack, VE2CV

_____________________________________________
John S. (Jack) Belrose, PhD Cantab, VE2CV
Senior Radioscientist
Radio Sciences Branch
Communications Research Centre
PO Box 11490 Stn. H
OTTAWA ON K2H 8S2
CANADA
TEL 613-998-2779
FAX 613-998-4077
e-mail <john.belrose_at_crc.ca>
_____________________________________________
Received on Thu Feb 11 1999 - 19:39:29 EST