Vertical ant experts, I need info
steve.m.zettel at internet.nps.usace.army.mil
steve.m.zettel at internet.nps.usace.army.mil
Wed May 22 16:20:34 EDT 1996
Steven (GREAT name!),
Though far from an expert, here is my experience with tilted
I haven't yet modeled the tilted vertical in AO or NEC/Wires, but I've
used the Navy's standard 35' vertical whip (with autotuner located at
its base) for tactical and long-haul HF comms in several Inshore
Undersea Warfare Units, including a two-year stint as Comm Officer in
one of the units. Doctrine states, and is borne out by real-world
experience, that as the vertical is leaned over toward horizontal the
useful component of radiation becomes increasingly higher angle (and
somewhat attentuated). At almost horizontal the antenna is a NVIS
(near vertical incidence scatter) radiator, suited for close-in comms.
In this mode, frequencies are varied to ensure that an appreciable
amount of signal is returned to earth as ionospheric conditions
change throughout the 24 hour period. Some IUW units have gone as far
as to make base mounts that allow one of our two whips to be
continuously shifted from vertical to horizontal as tactical and
propagational conditions change. At small angles from vertical (to
perhaps 30 degrees off vertical) I've noted no perceptible difference
from a vertical radiator. At 45 degrees some effect is evident, as
much from the absence of distant stations as from any enhancement of
close in stations. As the antenna goes from 45 degrees to horizontal,
the effect can be dramatic--close in stations previously unreadable in
the "skip zone" can now be copied reliably. However, overall signal
strength often falls off too.
The application for all of this would as a Sweepstakes antenna, where
long haul, low angle propagation would probably not be as useful as a
higher angle radiator. However, a medium to low dipole or horizontal
loop would serve as well, and have the advantages of higher efficiency
and less induced noise, particularly in the case of a horizontal loop
operated at it's fundamental frequency or second harmonic. The short
vertical operated over ground is a notoriously inefficient radiator.
We get away with using it in the Navy because of our (usually) close
proximity to the saltwater ground plane.
Two books on the subject of tactical HF communications, NVIS, and NVIS
radiators called, aptly enough "HF Tactical Communications, VOL I and
II" are available from Craig Clark's (N1XG) Amateur Radio Bookstore.
They are interesting reading, although the author does put in plugs
for equipment he or his company manufactures.
Hope this helps. If I can be of further assistance e-mail me at this
address or kj7ch at libby.org
Steve Zettel KJ7CH kj7ch at libby.org
Libby, MT USA steve.m.zettel at usace.army.mil
______________________________ Reply Separator _________________________________
Subject: Vertical ant experts, I need info
Author: steven at zianet.com (Steven Nace KN5H) at Internet
Date: 5/22/96 12:01 PM
What, if any effect does a 'tilt' in my vertical have in its performance? My
R7, for lack of a better word, leans a lot. This less than vertical
orientation is due to high winds. The question is, how much can I tolerate
before there is a change in its performance.
Thanks in advance
73 de Hose KN5H
>From WD8AUB at IX.NETCOM.COM (Douglas L. Klein) Wed May 22 22:35:31 1996
From: WD8AUB at IX.NETCOM.COM (Douglas L. Klein) (Douglas L. Klein)
Date: Wed, 22 May 1996 17:35:31 -0400
References: <Chameleon.960522152001.k4sb at k4sb.avana.net>
Message-ID: <31A388A3.6D74 at IX.NETCOM.COM>
k4sb at avana.net wrote:
> For your information, all the calls I mentioned are perfectly legal to use during
> 4-1-96 to 8-31-96. I'm not making up some phony prefix.
> Name: ed sleight
> E-mail: k4sb at avana.net
> Date: 05/22/96
> Time: 15:18:22
> This message was sent by Chameleon
You missed the point. But, it is probably just as well that you did....
>From tomf at neca.com (Tom Francis) Wed May 22 23:50:54 1996
From: tomf at neca.com (Tom Francis) (Tom Francis)
Date: Wed, 22 May 1996 18:50:54 -0400
Subject: IARU es CW Treaty requirement
Message-ID: <199605222250.SAA05333 at orion.neca.com>
I am formally on the record with the FASC
as opposing the dropping of the CW treaty
requirement as part of the IARU position
I've sent a message (snail and e) to the ARRL and
the IARU FASC concerning my opposition to the dropping
of CW as a treaty requirment for member nations
and will not repeat it here for the sake of
However, I have waded through the 22 page "discussion"
paper and can not help but think that the CW issue
is closed and that in fact the CW will be deleted
as a treaty requirement for the amateur service. Section
4 and and 9.12 through 9.14 are particularly telling.
It's done folks.
In any case, those of us who would prefer to keep
the CW treaty requirement should raise the flag and
let our IARU representative, in this case the ARRL,
know of our opposition.
Tom Francis, NM1Q (tomf at neca.com)
>From km9p at contesting.com (Bill Fisher, KM9P) Thu May 23 01:31:22 1996
From: km9p at contesting.com (Bill Fisher, KM9P) (Bill Fisher, KM9P)
Date: Wed, 22 May 1996 20:31:22 -0400 (EDT)
Subject: N6TJ's Swapping CQWW Weekends
Message-ID: <199605230031.UAA25701 at paris.akorn.net>
I fully support NOT messing with CQWW. I'm sure nothing will change, but
just in case they are thinking about it...
>From my perspective:
SSB contests should be during periods of more light. If you really want to
switch some contests, the WPX weekends should be switched. Moving the SSB
contest to a weekend where there is more dark, would mean moving the contest
(in spectrum) to bands that have less available (usefull) spectrum. Which
means less enjoyment for the majority since only the biggest signals will be
able to occupy the small amount of spectrum. Keeping SSB contests on 20, 15
and 10 is best.
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