6 meter ant. how hi ? ?????

[kc5cqa]

I read in this news group a while back on the best height for a six
meter antenna, if I recall right someone was saying that one
wavelength above ground,,,,, I think,,,,,,I understand it will work
better the higher it is,,,,,,,,,,,,,,,,,,,,,,, but what I wanted to
know ,,,,, what was the least elevation above ground that would work
really well. Appreciate your refreshing my memory. thanks. Chuck
Lorentson "73"

[Cecil]

Which are you most interested in, sky wave or ground wave?
--
http://www.mindspring.com/~w6rca

[Richard Harrison]

Cecil asked the right question. You want sky wave or ground wave?

For sky wave you only need 1/2-wave antenna elevation for near optimum
performance, if you are in the clear. That would be only about 10 feet.

For line of sight communications along the ground, the horizon is about
5 miles from an elevation of 10 feet. The horizon in miles is about the
square root of twice the elevation of the antenna in feet.

So, for local communications, you need a lot of antenna height to
communicate line of sight over long distances because the earth is
curved and obstructions tend to interfere.

Best regards, Richard Harrison, KB5WZI

[KG4FET]

Chuck,
I have my 3 element home brew at 42 ft. This works FB on both local and long
distance coms on 6 meters. Fun band and with a minimum of equipment you can
have a great time dxing the 6 meter band.
73 and see you on 6 meters de KG4FET Sandor EM90 Proud FT 100 owner

[Bob Miller]

kc5cqa <kc5...@devtex.net> wrote:

A vertical ground plane antenna of aluminum tubing worked fine at 15
feet with 5 watts. You don't need much when 6 meters is open.

Bob

[Reg Edwards]

An antenna on any band will work at very high efficiency
(>90%) when 3/8ths or more wavelengths above any sort of
ground. For the 6 metre band that's anywhere above 8 feet.
And even as low as 5 feet you will get around very well.

What REALLY matters is height above obstructions in the
immediate vicinity. A satisfactory height in New York City
is 8 feet above the Empire State Building. But at the
bottom of the Colorado Canyon you have REAL problems.
--
***********************************
Regards from Reg, G4FGQ
For free radio modelling software go to:
http://www.btinternet.com/~g4fgq.regp

***********************************

[Reg Edwards]

[Richard Harrison]

Reg wrote:
"A satisfactory height in New York City is 8 feet above the Empire State

Building. But at the bottom of the Colorado Canyon you have real
problems."

Exactly right. Some folks realize this is true only because the 6 metre
band is usually not propagated by the ionosphere as it is above the
maximum usable frequency. Others may miss the point that 50 MHz is
usually only good for line-of-sight paths.

For ionospheric propagation, 1/2-wave antenna elevation is enough. For
line-of-sight, the elevation needed is whatever it takes.

I spent a week rafting down the Grand Canyon. Medium wave reception was
near zero. Shortwave reception at the bottom of the canyon was actually
very good.

[Mark Keith]

Richard Harrison wrote:

>
> I spent a week rafting down the Grand Canyon. Medium wave reception was
> near zero. Shortwave reception at the bottom of the canyon was actually
> very good.
>
> Best regards, Richard Harrison, KB5WZI

One reason why I like the lower hf bands when camping. You have the same
problem even in the fairly shallow river bottoms here in TX. I kayak on
a few of them in the hill country. Being I'm usually on 80/40 meters and
working regional, it doesn't hurt me much at all. But try to tune a
local 2m repeater? Might as well hang it up, or get in the car and drive
up the hill to get out of the "rut". But I string low dipoles up that
aren't ten ft off the ground and I'm below grade 80 ft, and still do
fine on 80/40. Even the higher hf bands will work ok usually. Ten meters
would see a big cut if working local or dx though. MK
--
http://web.wt.net/~nm5k

[Bill Turner]

On Fri, 15 Dec 2000 07:08:03 -0600, Mark Keith <nm...@wt.net> wrote:

>But I string low dipoles up that
>aren't ten ft off the ground and I'm below grade 80 ft, and still do
>fine on 80/40. Even the higher hf bands will work ok usually. Ten meters
>would see a big cut if working local or dx though.

_________________________________________________________

Similar experience here. When mobiling, 80 and 40 get out equally well whether
I'm out in the open or down in a valley. On 20 I begin to notice the valley
effect; on 15 and 10 it is quite pronounced. Above that it's almost line of
sight.

w7ti

[Vincent Mcshane]

A general rule of thumb with HF antennas is that it should be a quarter
wavelength of the ground. This is not always possable so a good rule is to
go down in steps, after a quarter an eigth then a sixteenth etc etc,
anything below about 2 metres and you will get near vertical instant skywave
(NVIS) this is due to the jump to the ground being so short the trajectory
of take of for the signal is very tight, this is good for valleys and areas
of dense forrest but lessens the distance the signal will travel, unless,
you are very close to and trying to TX over water, which will boost your
signal with every skip. I hope this helps even a little bit.

Cheers for taking the time to read this

Vince
Bill Turner <w7...@jps.net> wrote in message
news:816l3t8dqasm01o0r...@4ax.com...

[Richard Harrison]

Vincent Mcshane wrote:
"A general rule of thumb with HF antennas is that it should be a quarter
wavelength of the ground."

Quarter-wave vertical antennas are resonant.
But, a dipole 1/4-wave above ground gives maximum radiation straight up.
It`s a great cloud-warmer. !/4-wave dipole elevation produces the lowest
height at which the approximate free-space drivepoint impedance of near
70 ohms occurs, but a dummy load has the same attribute.

1/2-wave elevation of the horizontal dipole produces the first overhead
null so that the radiation obliquely emerges from the antenna at angles
very useful for distant communications.

At 1/2-wave above ground, the dipole again produces a drivepoint
impedance near 70 ohms. This is a repetitive characteristic. Maximum
radiation is near an angle of 30 degrees with the earth, and broadside
to the antenna wire.

At heights above 1/2-wave, the lowest radiation angle drops below 30
degrees as the antenna elevation rises, but additional radiation angles
appear which take away energy from the low-angle lobes.

1/2-wavelength is usually the ideal height for a horizontal dipole.
1/4-wavelength is usually not good for DX.

[Vincent Mcshane]

I owe Bill Turner an apology. I made a mistake and I am now very sorry I
jumped the gun and started getting ratty without getting all the facts

I therefore apologise unreservedly
Sorry Bill
Vince McShane

Bill Turner <w7...@jps.net> wrote in message
news:816l3t8dqasm01o0r...@4ax.com...

[Donald Whiteman, KK9H]

I believe I saw that post and I think its author mentioned 30 feet was
his recommended optimal height above ground for a 6M antenna. Just
coincidentally, I have a 6M halo antenna mounted on a chimney that is
about that height and it works great for me. 73