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Old June 7th 06, 05:34 AM posted to rec.radio.amateur.antenna
blair thompson
 
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Default End-fed wire question.

I have a 63 ft. end-fed wire antenna which I am using with an MFJ-949
versa tuner, and 4 counterpoises cut for 1/4 wave on 15,20, 30 and 40
meters. Far end not very high, about 25 feet up a tree, shot up there
with a slingshot. Pretty thick foliage right now, but not a lot of the
wire is showing and in the clear as the near end of the wire slopes
down almost to ground level (townhome QTH).

Bit of an underperformer, and I was wondering whether it would be
worth my while to install a ground rod in order to ground the tuner,
and whether that might improve matters a bit,

Thanks for any information.
Blair VA7NA
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Old June 7th 06, 06:48 AM posted to rec.radio.amateur.antenna
Reg Edwards
 
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Default End-fed wire question.


"blair thompson" wrote
I have a 63 ft. end-fed wire antenna which I am using with an

MFJ-949
versa tuner, and 4 counterpoises cut for 1/4 wave on 15,20, 30 and

40
meters. Far end not very high, about 25 feet up a tree, shot up

there
with a slingshot. Pretty thick foliage right now, but not a lot of

the
wire is showing and in the clear as the near end of the wire slopes
down almost to ground level (townhome QTH).

Bit of an underperformer, and I was wondering whether it would be
worth my while to install a ground rod in order to ground the tuner,
and whether that might improve matters a bit,

=================================
Blair,
A single ground rod will be virtually useless - that is unless it can
be driven into salt sea water.

If the radials are elevated above ground, then some improvement may be
achieved by allowing them to rest at ground level. This will increase
the effective height of the antenna.

Better still, shallow-bury them.

Even better, add more radials. Extra radials, on or underground, need
not be very long and not of any particular length. The more there are
up to a dozen or so, the merrier.

Important - try to get the near end of the wire as high as you can in
the air. Get some vertical wire into it. Can the near end be taken up
the side of the house and suspended from a chimney, TV antenna or rain
gutter or something? This will definitely make a noticeable
improvement.
----
Reg.


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Old June 7th 06, 02:53 PM posted to rec.radio.amateur.antenna
chuck
 
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Default End-fed wire question.

Reg Edwards wrote:
"blair thompson" wrote
I have a 63 ft. end-fed wire antenna which I am using with an

MFJ-949
versa tuner, and 4 counterpoises cut for 1/4 wave on 15,20, 30 and

40
meters. Far end not very high, about 25 feet up a tree, shot up

there
with a slingshot. Pretty thick foliage right now, but not a lot of

the
wire is showing and in the clear as the near end of the wire slopes
down almost to ground level (townhome QTH).

Bit of an underperformer, and I was wondering whether it would be
worth my while to install a ground rod in order to ground the tuner,
and whether that might improve matters a bit,

=================================
Blair,
A single ground rod will be virtually useless - that is unless it can
be driven into salt sea water.


In which case, it will be practically perfect! Not
much gray area for ground rods in this
Zoroasterian space. ;-)

Well, as far as ground rods are concerned, it
would be practically perfect, but your antenna as
is would still not be.

If the radials are elevated above ground, then some improvement may be
achieved by allowing them to rest at ground level. This will increase
the effective height of the antenna.

Better still, shallow-bury them.

Even better, add more radials. Extra radials, on or underground, need
not be very long and not of any particular length. The more there are
up to a dozen or so, the merrier.


If the antenna is roughly a half-wave on 40
meters, mostly horizontal, I doubt that more
radials will help much.

Important - try to get the near end of the wire as high as you can in
the air. Get some vertical wire into it. Can the near end be taken up
the side of the house and suspended from a chimney, TV antenna or rain
gutter or something? This will definitely make a noticeable
improvement.
----
Reg.



If you are seeking more low-angle radiation for
DX, then this will help and you may see more
benefit from additional radials. You might
consider attaching the guy to the chimney, etc.,
and running the "vertical" wire from the tuner up
and away from the house. You don't want that
vertical wire running right alongside the chimney
or TV antenna support.

Chuck

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Old June 7th 06, 11:24 AM posted to rec.radio.amateur.antenna
BKR
 
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Default End-fed wire question.



blair thompson wrote:
I have a 63 ft. end-fed wire antenna which I am using with an MFJ-949
versa tuner, and 4 counterpoises cut for 1/4 wave on 15,20, 30 and 40
meters. Far end not very high, about 25 feet up a tree, shot up there
with a slingshot. Pretty thick foliage right now, but not a lot of the
wire is showing and in the clear as the near end of the wire slopes
down almost to ground level (townhome QTH).

Bit of an underperformer, and I was wondering whether it would be
worth my while to install a ground rod in order to ground the tuner,
and whether that might improve matters a bit,

Thanks for any information.
Blair VA7NA



End fed wires must always be used against an efficient ground system
consisting of a large number of radials or a tuned counterpoise for each
frequency.

A single ground rod is normally fairly poor.
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Old June 7th 06, 08:58 PM posted to rec.radio.amateur.antenna
Roy Lewallen
 
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Default End-fed wire question.

BKR wrote:

End fed wires must always be used against an efficient ground system
consisting of a large number of radials or a tuned counterpoise for each
frequency.

A single ground rod is normally fairly poor.


It depends on the length of the wire. If it's near an odd number of
quarter wavelengths long, the radiation resistance between the end and
ground will be low, and a good ground system is necessary to get good
efficiency. If it's significantly shorter than a quarter wavelength, the
resistance is lower yet and a very good system is required. On the other
hand, if it's close to an integral number of half wavelengths, the
resistance will be high, and you can get by with a very poor ground
system -- in many cases just a ground rod -- without sacrificing a
significant amount of efficiency.

That's the reason why a half wave antenna works so well on an HT.

Roy Lewallen, W7EL


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Old June 7th 06, 09:44 PM posted to rec.radio.amateur.antenna
Bob
 
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Default End-fed wire question.

My end fed inverted "L" goes up 20 feet and then out 75 feet, with the far
end about 25' high. It is fed with a homebrew remote controlled tuner (50'
from shack), simple series roller inductor and a parallel capacitor on the
output. Ground system is about 6 pieces of various 20 to 30 foot lengths of
wire, in a sort of random star shape, buried about 2".
It generally outperformed a dipole I had up with an A/B switch to compare
the two. The dipole was 25' up, 65 feet long and fed with ladder line from a
link coupled tuner. The dipole was a tad quieter, but the "L" received and
transmitted maybe an S unit better.
I've read in more than a few places that you need to get the vertical part
as high as possible before it heads on out to the woods.
Bob
KB8TL



"blair thompson" wrote in message
...
I have a 63 ft. end-fed wire antenna which I am using with an MFJ-949
versa tuner, and 4 counterpoises cut for 1/4 wave on 15,20, 30 and 40
meters. Far end not very high, about 25 feet up a tree, shot up there
with a slingshot. Pretty thick foliage right now, but not a lot of the
wire is showing and in the clear as the near end of the wire slopes
down almost to ground level (townhome QTH).

Bit of an underperformer, and I was wondering whether it would be
worth my while to install a ground rod in order to ground the tuner,
and whether that might improve matters a bit,

Thanks for any information.
Blair VA7NA



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