Did they mention where an actual drawing can be found
or if an indepth descriptive article can be found?
Thanks
Art
"Fractenna" wrote in message
...
There were about 80 people at the talk, including a number of hams who
are/were
antenna professionals; academics; and so on. I was there for most of it;
it was
two hours and thus had the time frame for a substantial brief.

I saw and heard nothing that--in my opinion-- constitutes 'new' or
'revolutionary'. Although the statement "97% efficiency " was made for a
shortened, DLM by Mr. Vincent, I saw no data that supported that claim. I
did
not see wide bandwidths in the data. The antennas are small. That claim is
supported.

I did not see any evidence of improvement over the extant art of
distributed
loading. What I saw essentially confirms my earlier comments from June and
July
in this forum. Note: I was not aware of Mr. Vincent's design for the DLM
until
yesterday.

If I missed something, or make a statement here that is factually
inaccurate
regarding the statements of Mr. Vincent, apologies ahead of time; and
please
fill me in on this forum.

As promised earlier relative to the extant prior art: I draw reference to
an
existing, patent pending, commercial antenna by our friends at Astatic
(the
microphone company). It is sold by Omnitronics. It is called the "3K
Antenna".
The antenna is targeted for CB'ers and truckers, but it also works and is
used,
by hams on 10M. It , in appearance, looks identical to some of the DLM
antennas
Mr. Vincent presented. There is an inside cutaway which shows, in part , a
vertically oriented helix (linear load); a "midsection"; a loading coil;
and a
top whip. I have one here. See:

http://www.astatic.com

Mr. Vincent confirmed that he was unaware of the Astatic antenna until I
mentioned it to him yesterday.

I have offered to elaborate on a critique of Mr. Vincent's technology on
the
web, which I will produce, if needed. It may not be necessary for me to
educate
this way, as a number of people were/are capable of such assessments based
on
the info provided, and Mr. Vincent stated that he will post the PPT of the
talk
on the web. Doubtless there will be further independent discussion.

Just as a matter of protocol, in a public talk that has benefited from
many
years of guidance under an academic physics department, may I make the
following brief (albeit not complete) suggestions:

1) Understand that a widely spaced helix has air cooling such that the
cooling
rate can substantially exceed the heating rate. Therefore the helix may
dissipate heat and does not heat up much. That does not mean the system is
lossless, nor that the efficiency through the helix is high.

2) Never claim that the efficiency of any electronic component as 100%
("lossless through the helix") just because the current profile stays
relatively flat across it, and it doesn't burn up.

3) We have all used chicken wire(as ground screens), but may it strongly
be
discouraged. The losses are frequency dependent and often high;

4) Do not discount any ground counterpoise--especially one with 1/8 wave
radials as being --in considering monopoles. It is an antenna system. This
is
part of the system;

5) Avoid PVC in monopole construction. At some frequencies the losses are
reasonable, at others it is high. It varies from manufacturer; thickness;
and
so on.

6) Do not compare gains on a thin-wire type 1/4 wave monopole to a thick
(diameter) helix-based antenna with a far larger electrical length, over
a
lossy, small counterpoise, and infer the efficiency.

7) Do not use wood in the near field when using MF/HF for probe
measurements.

My brief thoughts at moment. More later if needed.

73,
Chip N1IR