The antenna will work OK. The VSWR may be a little high due to the low
height. Minimum height should be in excess of 65 feet and most hams
can't get that high!

Working on 20 meters will most likely be difficult without a good tuner.

Deacon Dave, W1MCE

whitehat wrote:

I will be building a center fed 80 m dipole, 62.5 feet
each side of center. The ends will be about 23 feet above
ground but the center is not supported to it sags to about
18 feet. I will feed it directly with about 25 feet of
RG-213 50 ohm coax and connect it to an antenna tuner in
the shack that can tune from 50 to 500 ohms.

This should work okay on 80 m, right?

How well will it do on 20 m?

whitehat wrote:
I will be building a center fed 80 m dipole, 62.5 feet
each side of center. The ends will be about 23 feet above
ground but the center is not supported to it sags to about
18 feet. I will feed it directly with about 25 feet of
RG-213 50 ohm coax and connect it to an antenna tuner in
the shack that can tune from 50 to 500 ohms.

This should work okay on 80 m, right?

How well will it do on 20 m?


Any way to get the centre up higher?
With some kind of a pole?
Eskay

For bands other than 80 you would be better off with a balanced feed line
than with the coax.

JD
KA9CAR


"whitehat" wrote in message
...
I will be building a center fed 80 m dipole, 62.5 feet
each side of center. The ends will be about 23 feet above
ground but the center is not supported to it sags to about
18 feet. I will feed it directly with about 25 feet of
RG-213 50 ohm coax and connect it to an antenna tuner in
the shack that can tune from 50 to 500 ohms.

This should work okay on 80 m, right?

How well will it do on 20 m?

whitehat,
Yes, it will work on 80 meters. Don't count on
using it on 20 meters. Depending on the tuner it
may 'tune', but you won't have the 'best' results.
'Doc

I will be building a center fed 80 m dipole, 62.5 feet
each side of center. The ends will be about 23 feet above
ground but the center is not supported to it sags to about
18 feet. I will feed it directly with about 25 feet of
RG-213 50 ohm coax and connect it to an antenna tuner in
the shack that can tune from 50 to 500 ohms.

This should work okay on 80 m, right?

How well will it do on 20 m?


For 80 it will work fine for the heights you have to work with. As most
always the higher the beter. If you want to work 20 meters or other bands
with the same antenna you might want to feed it with open wire or go to an
off center fed or (yuck) maybe the g5rv type.

You will be a much happier camper if you feed it with 450 ohm ladder line.
You will have no trouble using the antenna anywhere from 80 to 10, and if
the ladder feed is more than 70 feet you will be able to load the dipole on
160. If the feed line is not 70 feet long, you still will be able to use
the antenna on 160, just join the two sides of the feedline together and
treat as a longwire.

--
73 es cul

wb3fup
a Salty Bear

"Ralph Mowery" wrote in message
...
I will be building a center fed 80 m dipole, 62.5 feet
each side of center. The ends will be about 23 feet above
ground but the center is not supported to it sags to about
18 feet. I will feed it directly with about 25 feet of
RG-213 50 ohm coax and connect it to an antenna tuner in
the shack that can tune from 50 to 500 ohms.

This should work okay on 80 m, right?

How well will it do on 20 m?


For 80 it will work fine for the heights you have to work with. As most
always the higher the beter. If you want to work 20 meters or other
bands
with the same antenna you might want to feed it with open wire or go to
an
off center fed or (yuck) maybe the g5rv type.

"'Doc" wrote in message ...


whitehat,
Yes, it will work on 80 meters. Don't count on
using it on 20 meters. Depending on the tuner it
may 'tune', but you won't have the 'best' results.
'Doc

Perhaps basic antenna theory needs to be revisited here (?).


A center fed half wave antenna using standard 50 to 70 ohm coax will operate
with a 'reasonable' SWR at the ODD multiples of the fundamental.

Nice and simple.

Dan/W4NTI

Dan,
And compared to a 20 meter dipole, the 80 meter
dipole will stump it's toe on 20 meters.
'Doc

'Doc wrote:
And compared to a 20 meter dipole, the 80 meter
dipole will stump it's toe on 20 meters.

As a matter of interest, I just did an A/B comparison between
my 80m dipole and my 20m rotatable dipole. The guy in CA
couldn't tell any difference in transmitted signal levels
and I couldn't tell any difference in received signal levels.
In other words, in four directions, my 130ft dipole works
just as well on 20m as my resonant 20m rotatable dipole.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil,
Now all you have to do is get everyone to move so
that they are in one of those four directions from you.
'Doc