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Old June 11th 05, 03:26 PM
Cecil Moore
 
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Fred W4JLE wrote:

Anecdotal evidence. First note he says 160 meter G5RV, one could assume he
has doubled the size to 204 feet to meet this claim. Run a 204 foot dipole
through EZNEC on 40 and you can see why the claims may be valid in some
directions.


I didn't look at it but just noticed 'nvis' in the title.
Of course, a dipole at 7 feet will have near-vertical gain
over a G5RV at 50 feet. Near-vertical gain is NOT what the
majority of hams desire. Near-vertical gain is the antithesis
of DX.

"William Taylor" wrote in message
...

http://www.hamuniverse.com/supernvis.html

The claim is that a dipole 7 feet off the ground has
a 10db gain over a G5RV at 50 feet.

Is that possible, or hype?


--
73, Cecil http://www.qsl.net/w5dxp

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Old June 11th 05, 08:24 PM
Ed
 
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I didn't look at it but just noticed 'nvis' in the title.
Of course, a dipole at 7 feet will have near-vertical gain
over a G5RV at 50 feet. Near-vertical gain is NOT what the
majority of hams desire. Near-vertical gain is the antithesis
of DX.



I differ on that opinion. My 40M/80M operational preferences are
definitely for close-in communications, such as getting on the Noon-Time
net, various in-state 75M nets, and other "local" activities". The lower
noise factor of the NVIS antenna helps, too. Of course, its best to have
two antennas, one such as NVIS and another well placed dipole, for optimum
choice.


Ed K7AAT
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Old June 11th 05, 09:00 PM
Cecil Moore
 
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Ed wrote:

I didn't look at it but just noticed 'nvis' in the title.
Of course, a dipole at 7 feet will have near-vertical gain
over a G5RV at 50 feet. Near-vertical gain is NOT what the
majority of hams desire. Near-vertical gain is the antithesis
of DX.


I differ on that opinion. My 40M/80M operational preferences are
definitely for close-in communications, such as getting on the Noon-Time
net, various in-state 75M nets, and other "local" activities". The lower
noise factor of the NVIS antenna helps, too. Of course, its best to have
two antennas, one such as NVIS and another well placed dipole, for optimum
choice.


What are you disagreeing with? How much DX do you work with
your NVIS antenna? Do you really think the majority of hams
are only interested in local communications on HF?
--
73, Cecil http://www.qsl.net/w5dxp

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Old June 11th 05, 09:25 PM
Ed
 
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What are you disagreeing with? How much DX do you work with
your NVIS antenna? Do you really think the majority of hams
are only interested in local communications on HF?


I guess my disagreement was with the word "majority"... but then, I was
thinking of 75M/40M and not the higher bands. I would say on the two bands
I meant to restrict my comments too, that more hams probably do communicate
"locally" rather than hunt DX.


Ed

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Old June 12th 05, 03:17 PM
Korbin Dallas
 
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On Sat, 11 Jun 2005 15:00:18 -0500, Cecil Moore wrote:

Ed wrote:

I didn't look at it but just noticed 'nvis' in the title.
Of course, a dipole at 7 feet will have near-vertical gain
over a G5RV at 50 feet. Near-vertical gain is NOT what the
majority of hams desire. Near-vertical gain is the antithesis
of DX.


I differ on that opinion. My 40M/80M operational preferences are
definitely for close-in communications, such as getting on the Noon-Time
net, various in-state 75M nets, and other "local" activities". The lower
noise factor of the NVIS antenna helps, too. Of course, its best to have
two antennas, one such as NVIS and another well placed dipole, for optimum
choice.


What are you disagreeing with? How much DX do you work with
your NVIS antenna? Do you really think the majority of hams
are only interested in local communications on HF?


Yes the majority of hams are indeed interested in Local HF communications
on 80 & 40. Something that will reliably commutate out to 300-400
miles.

When they think of DX they think 20 - 10 meters.

Those that are interested in DX on 80 meters are a very small minority.


--
Korbin Dallas
The name was changed to protect the guilty.



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Old June 12th 05, 04:07 PM
Cecil Moore
 
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Korbin Dallas wrote:
What are you disagreeing with? How much DX do you work with
your NVIS antenna? Do you really think the majority of hams
are only interested in local communications on HF?


Yes the majority of hams are indeed interested in Local HF communications
on 80 & 40. Something that will reliably commutate out to 300-400
miles.


They can get that from a 40 ft. high G5RV. No 7' high
NVIS dipole is needed. AND you can work DX on 20m-10m
with that 40 ft. high G5RV. I repeat, the majority of
hams are NOT interested *only* in local communications
on HF. A 7' high dipole is a poor performer on 20m-10m.
--
73, Cecil http://www.qsl.net/w5dxp

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Old June 12th 05, 08:37 PM
Ed
 
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They can get that from a 40 ft. high G5RV. No 7' high
NVIS dipole is needed. AND you can work DX on 20m-10m
with that 40 ft. high G5RV. I repeat, the majority of
hams are NOT interested *only* in local communications
on HF. A 7' high dipole is a poor performer on 20m-10m.



Cecil, since I started this thread with a comment on yours, in retrospect
I will admit what you say above is true! My comment applied to a small
particular group of operators on the lower bands (or is that higher bands?)



Ed K7AAT

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Old June 13th 05, 12:07 AM
Cecil Moore
 
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Ed wrote:
My comment applied to a small
particular group of operators on the lower bands (or is that higher bands?)


The top band is considered to be 160m so I assume "band" is
associated with wavelength, e.g. "160m band". So it appears
that higher bands = lower frequencies, but I could be wrong.
The IEEE Dictionary is no help. It thinks a "band" is a
track on a rotating memory device. :-)
--
73, Cecil http://www.qsl.net/w5dxp

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Old June 13th 05, 05:07 AM
 
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What are you disagreeing with? How much DX do you work with
your NVIS antenna? Do you really think the majority of hams
are only interested in local communications on HF?

Some are...Most work only the low bands...I know many
hams who couldn't care less about dx. They only talk to
other regional "good ole boys"....
But saying that, comparing a G5RV at 50 ft, against a
dipole at 7 ft, is fairly silly. The NVIS qualities are more
due to height above ground per wavelength, than the
length of the antenna.
Overall, I think the idea of running low dipoles, or using
ground screens, and pseudo "reflectors" etc, are
generally a waste of time.. If I were working NVIS on 75m,
I'd prefer a dipole at 50ft over one at 7 ft. It will have lower
ground losses, and I'd be willing to bet the NVIS performance
would be just as good as the low antenna. But, the medium
range performance would be a good bit better. Also, you
can work dx also...I've worked dx on 75m, using a dipole
at 35 ft...It's no big deal really...Just finding the DX to talk to
is more difficult. Also...NVIS antennas are not low noise,
unless they are defective in some way...They may reduce
the reception of far off lightning, if that static arrives at
low angles.. A low dipole has great reception of noise...
Straight up....A low to medium height dipole already has
enough gain straight up. I don't really want to enhance it
further...I also want to have decent performance on longer
paths...Listen to all the BIG strappers on 75m...I bet very few
are running real low dipoles with screens...Most will be running
higher dipoles hung from towers, trees, etc...
MK

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Old June 13th 05, 05:40 AM
Ed
 
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What are you disagreeing with? How much DX do you work with
your NVIS antenna? Do you really think the majority of hams
are only interested in local communications on HF?


As you may have missed previously, my comments were directed from the
standpoint of a 75M/40M operator. Personally, I don't consider a NVIS
antenna a valid antenna above those bands. So, for the two bands I have in
mind, Yes, I believe the majority of operators there are interested in
local/intra-state communications.


Ed


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