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Comcast newsgroups February 28th 07 08:39 PM

Effect of raising vertical antenna higher
 
Hello all,

I have a mono-band 20-meter vertical currently mounted only about
12 feet up (less than a quarter wave). There are 4 radials and it tunes
very well - very low VSWR across entire band, with decent signal reports.

Question: If I were to rent a cherry picker, I could mount the thing on
the end of the peak of my house, at about 40 feet up. That would put the
bottom of the radials at greater than 1/4 wave.

But would I notice any difference? If so, would it be potentially
dramaticly
better, or just 'technically' better? It would be a major project to do, so
I'm
trying to decide if it would be worth it or not.

Thanks,

Dave WB7AWK



John Smith February 28th 07 09:00 PM

Effect of raising vertical antenna higher
 
Comcast newsgroups wrote:
Hello all,

I have a mono-band 20-meter vertical currently mounted only about
12 feet up (less than a quarter wave). There are 4 radials and it tunes
very well - very low VSWR across entire band, with decent signal reports.

Question: If I were to rent a cherry picker, I could mount the thing on
the end of the peak of my house, at about 40 feet up. That would put the
bottom of the radials at greater than 1/4 wave.

But would I notice any difference? If so, would it be potentially
dramaticly
better, or just 'technically' better? It would be a major project to do, so
I'm
trying to decide if it would be worth it or not.

Thanks,

Dave WB7AWK



Dave:

"Higher the better" is the golden rule.

I'd venture it would be noticeably better. But, rent a cherry picker?
I usually find much more reasonable ways to achieve decent heights ...

JS

Tam/WB2TT February 28th 07 09:28 PM

Effect of raising vertical antenna higher
 

"Comcast newsgroups" wrote in message
. ..
Hello all,

I have a mono-band 20-meter vertical currently mounted only about
12 feet up (less than a quarter wave). There are 4 radials and it tunes
very well - very low VSWR across entire band, with decent signal reports.

Question: If I were to rent a cherry picker, I could mount the thing on
the end of the peak of my house, at about 40 feet up. That would put the
bottom of the radials at greater than 1/4 wave.

But would I notice any difference? If so, would it be potentially
dramaticly
better, or just 'technically' better? It would be a major project to do,
so I'm
trying to decide if it would be worth it or not.

Thanks,

Dave WB7AWK

Download the free version of EZNEC, and run simulations at both heights. I
would look for differences in gain and vertical radiation angle.

Tam/WB2TT



chuck March 1st 07 02:45 AM

Effect of raising vertical antenna higher
 
Jon Kåre Hellan wrote:
"Tam/WB2TT" writes:

"Comcast newsgroups" wrote in message
. ..
Hello all,

I have a mono-band 20-meter vertical currently mounted only about
12 feet up (less than a quarter wave). There are 4 radials and it tunes
very well - very low VSWR across entire band, with decent signal reports.

Question: If I were to rent a cherry picker, I could mount the thing on
the end of the peak of my house, at about 40 feet up. That would put the
bottom of the radials at greater than 1/4 wave.

But would I notice any difference? If so, would it be potentially
dramaticly
better, or just 'technically' better? It would be a major project to do,
so I'm
trying to decide if it would be worth it or not.

Thanks,

Dave WB7AWK

Download the free version of EZNEC, and run simulations at both heights. I
would look for differences in gain and vertical radiation angle.

Tam/WB2TT


Don't forget that by raising the antenna, you avoid obstructions from your
house, neighbouring houses and foliage. I suspect those can be
significant.

73 de LA4RT Jon


And you reduce the effect of the ground beneath the antenna.

73,

Chuck NT3G

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Jon KÃ¥re Hellan March 1st 07 02:39 PM

Effect of raising vertical antenna higher
 
"Tam/WB2TT" writes:

"Comcast newsgroups" wrote in message
. ..
Hello all,

I have a mono-band 20-meter vertical currently mounted only about
12 feet up (less than a quarter wave). There are 4 radials and it tunes
very well - very low VSWR across entire band, with decent signal reports.

Question: If I were to rent a cherry picker, I could mount the thing on
the end of the peak of my house, at about 40 feet up. That would put the
bottom of the radials at greater than 1/4 wave.

But would I notice any difference? If so, would it be potentially
dramaticly
better, or just 'technically' better? It would be a major project to do,
so I'm
trying to decide if it would be worth it or not.

Thanks,

Dave WB7AWK

Download the free version of EZNEC, and run simulations at both heights. I
would look for differences in gain and vertical radiation angle.

Tam/WB2TT


Don't forget that by raising the antenna, you avoid obstructions from your
house, neighbouring houses and foliage. I suspect those can be
significant.

73 de LA4RT Jon

Buck March 1st 07 03:12 PM

Effect of raising vertical antenna higher
 
On Wed, 28 Feb 2007 12:39:36 -0800, "Comcast newsgroups"
wrote:

Hello all,

I have a mono-band 20-meter vertical currently mounted only about
12 feet up (less than a quarter wave). There are 4 radials and it tunes
very well - very low VSWR across entire band, with decent signal reports.

Question: If I were to rent a cherry picker, I could mount the thing on
the end of the peak of my house, at about 40 feet up. That would put the
bottom of the radials at greater than 1/4 wave.

But would I notice any difference? If so, would it be potentially
dramaticly
better, or just 'technically' better? It would be a major project to do, so
I'm
trying to decide if it would be worth it or not.

Thanks,

Dave WB7AWK



I don't know the minimum height above ground (in wave lengths) that
make the improvement in an antenna. However, Steppir antennas says
that an antenna on the ground needs 120 radials just to match one in
the air with two radials. I would like to know where the noticable
benefit of raising an antenna above the ground actually takes place
and where is the maximum benefit.

I know that the higher the better, but rather than that kind of
benefit, I am wondering from a ground standpoint where the benefits
start and where the point of diminishing returns begins.

Good luck with your antenna.


--
73 for now
Buck
N4PGW

Tam/WB2TT March 1st 07 09:10 PM

Effect of raising vertical antenna higher
 

"Buck" wrote in message
...
On Wed, 28 Feb 2007 12:39:36 -0800, "Comcast newsgroups"
wrote:

Hello all,

I have a mono-band 20-meter vertical currently mounted only about
12 feet up (less than a quarter wave). There are 4 radials and it tunes
very well - very low VSWR across entire band, with decent signal reports.

Question: If I were to rent a cherry picker, I could mount the thing on
the end of the peak of my house, at about 40 feet up. That would put the
bottom of the radials at greater than 1/4 wave.

But would I notice any difference? If so, would it be potentially
dramaticly
better, or just 'technically' better? It would be a major project to do,
so
I'm
trying to decide if it would be worth it or not.

Thanks,

Dave WB7AWK



I don't know the minimum height above ground (in wave lengths) that
make the improvement in an antenna. However, Steppir antennas says
that an antenna on the ground needs 120 radials just to match one in
the air with two radials. I would like to know where the noticable
benefit of raising an antenna above the ground actually takes place
and where is the maximum benefit.

I know that the higher the better, but rather than that kind of
benefit, I am wondering from a ground standpoint where the benefits
start and where the point of diminishing returns begins.

Good luck with your antenna.


--
73 for now
Buck
N4PGW


I decided to run EZNEC on a 20 m vertical with 4 radials sloping 45 degrees.
Here is what I got:

HEIGHT GAIN V-ANGLE

15 ft 0.1dbi 19 deg
32 0.54 14 deg
40 1.25 47
0.51 12
100 3.31 8


The 40 foot height has a double lobe, but the gain at 12 degrees is more
than the 15 foot gain at 19 degrees. Now I know why the DL I worked on 20,
with a vertical on the roof of a 24 story apartment building sounded so
good.

Tam/WB2TT



[email protected] March 2nd 07 12:12 AM

Effect of raising vertical antenna higher
 
On Mar 1, 9:12 am, Buck wrote:
However, Steppir antennas says
that an antenna on the ground needs 120 radials just to match one in
the air with two radials.


That would only apply to an elevated antenna 1/2 wave or higher up
though..

I would like to know where the noticable
benefit of raising an antenna above the ground actually takes place
and where is the maximum benefit.

I know that the higher the better, but rather than that kind of
benefit, I am wondering from a ground standpoint where the benefits
start and where the point of diminishing returns begins.


Just depends on the band, the path/angle used most of the time, the
ground quality, etc, etc.. Raising it to 40 ft from 12 feet would make
a
noticable difference if you compare all the various types of paths.
IE:
Just the local ground/space wave will be improved a good bit.
As far as the ionosphere, would effect farther off stations more,
than closer in. It's possible for the low antenna to be nearly as
good on a short/medium hops, but DX will be better on the higher
antenna and possibly open/close the band a bit earlier/later.
Ground loss will be lower, but I'm not sure it's worth the cost of
the
cherry picker.. I'd tend to say not, being a cherry picker is usually
not cheap.. Being the current antenna is just a bit less than a 1/4
wave up, it's not in near a bad a shape as say a 80 or 40 antenna
at that height in feet.
MK


R.A Abrahams March 3rd 07 12:03 PM

Effect of raising vertical antenna higher
 
question what is the effect of raising a vertical
practical or theoretical ?
Nice answers to think it all over
Practical the higher the better why
from own experiments a long time ago on 26 security , 145 ham 151 privat
and 156 nautical
the following to think
higher is better in my case optical horizon and the reach of the tx
an other effect to mention is human noise the higher the antenna the less
noise that is a practical profit
one of the group mentioned mechanical aspect notice
radials said an other 120 is that practical only 1 practical is enough
use your radials as quide ropes and you may solve a supportproblem
mind that the angel of the rial(s) and erected radiator effetcts the
radiationresistor 90 degrees . 35 ohm 180 degrees 75
120 degrees about 50 ohms and al between
Mind that a higher vertical is more sensitive for statics solve that effect
by resitor or neonbulb(lightning protection
I like your dicussions however some things are not know at the other side
of the swimmingpool
73 and 55 fde ruud PA0rab


schreef in bericht
oups.com...
On Mar 1, 9:12 am, Buck wrote:
However, Steppir antennas says
that an antenna on the ground needs 120 radials just to match one in
the air with two radials.


That would only apply to an elevated antenna 1/2 wave or higher up
though..

I would like to know where the noticable
benefit of raising an antenna above the ground actually takes place
and where is the maximum benefit.

I know that the higher the better, but rather than that kind of
benefit, I am wondering from a ground standpoint where the benefits
start and where the point of diminishing returns begins.


Just depends on the band, the path/angle used most of the time, the
ground quality, etc, etc.. Raising it to 40 ft from 12 feet would make
a
noticable difference if you compare all the various types of paths.
IE:
Just the local ground/space wave will be improved a good bit.
As far as the ionosphere, would effect farther off stations more,
than closer in. It's possible for the low antenna to be nearly as
good on a short/medium hops, but DX will be better on the higher
antenna and possibly open/close the band a bit earlier/later.
Ground loss will be lower, but I'm not sure it's worth the cost of
the
cherry picker.. I'd tend to say not, being a cherry picker is usually
not cheap.. Being the current antenna is just a bit less than a 1/4
wave up, it's not in near a bad a shape as say a 80 or 40 antenna
at that height in feet.
MK




Dave Oldridge March 4th 07 01:09 PM

Effect of raising vertical antenna higher
 
wrote in news:1172794335.616945.165990
@n33g2000cwc.googlegroups.com:

On Mar 1, 9:12 am, Buck wrote:
However, Steppir antennas says
that an antenna on the ground needs 120 radials just to match one in
the air with two radials.


That would only apply to an elevated antenna 1/2 wave or higher up
though..


Actually, it need not be that high. Just decoupling an antenna from a
less-than decent ground will improve its gain. The ideal height for a 20m
antenna would be about 8m. Of course if you can put it up at ANY height,
then go for the 100m plus range, but if you can afford the hardware for
that, you can also afford the hardware to stack two beams!


--
Dave Oldridge+
ICQ 1800667


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