A Windom, a true Windom, is 1/2 wavelength long and fed 37% off of one
end with a SINGLE wire [not coax, not 450 ohm line, nothing but a single
wire].

There is no such thing as an end fed windom.

There is an end fed 1/2 wavelength DIPOLE that can be fed with 450
ladder line or 600 ohm open wire feeders and a good balanced line tuner.
It will work on the fundamental and all even harmonics.

So, a 130 foot dipole end fed with 600 or 450 line and a balanced tuner
will work just fine on 80, 40, 20, and 10 meters.

GeorgeF wrote:
I am currently using a 150' randomwire for 80 & 40 meters. Its
connected to the "wire" terminal of an MFJ-949 tuner. Been happy so far
with the conntacts made.

I'm considering taking an turning it into an endfeed windom simply by
running 450 ohm ladder line from the MFJ-949 to the top of my 30' mast
which current supports the randomwire. I'll be cutting the randomwire
at the mast and soldering one side of the 450 line while letting the
otherside of the 450 line not attached to anything.

Is there any advantage of doing this? Basically I'm taking a 150'
randomwire and turning it into about a 120' endfeed windom, will it be
worth the effort?

George

Hello George,

On my first reading, I imagined that you were considering
replacing the 30-foot, single-wire, vertical wire running
from your tuner to a 120-foot horizontal wire with a 30-foot
length of ladder line. Based on the responses so far, I
wonder if I correctly understood the question.

If my understanding of your question is correct, you now
have something like an inverted-L, with potentially
significant radiation from the vertical portion.

Changing the single wire to ladder line would probably
cancel most or all of the vertically polarized radiation and
would probably do little to improve the radiation from the
horizontal wire. You won't get much low-angle radiation from
a horizontal antenna at 30 feet, no matter how you feed it.

It is difficult to say whether you would notice an
improvement with your contemplated change. I'm inclined to
think not. A better move might be to consider putting down
some radials. What frequencies are involved here?

Also, as some of the responses suggest, there are divergent
views on the end-fed Zepp.

Be interested to hear how others see this.

Good luck.

Chuck


GeorgeF wrote:
I am currently using a 150' randomwire for 80 & 40 meters. Its
connected to the "wire" terminal of an MFJ-949 tuner. Been happy so far
with the conntacts made.

I'm considering taking an turning it into an endfeed windom simply by
running 450 ohm ladder line from the MFJ-949 to the top of my 30' mast
which current supports the randomwire. I'll be cutting the randomwire
at the mast and soldering one side of the 450 line while letting the
otherside of the 450 line not attached to anything.

Is there any advantage of doing this? Basically I'm taking a 150'
randomwire and turning it into about a 120' endfeed windom, will it be
worth the effort?

George

Cecil Moore wrote:
Bob Miller wrote:

But with an antenna tuner, couldn't the end-fed Zepp be multi-band?
That's what I see on page 7-2 of the arrl antenna book.

You can certainly use an end-fed Zepp on other bands but
it won't be a Zepp on those other bands. The definition of
a Zepp is 1/2WL long end-fed with 1/4WL open-wire feedline.

Also, unless the radiator is a multiple of 1/2WL, the feedline
will radiate. Seems a radiator length of (a multiple of 1/2WL
plus 1/4WL) would be worst case for feedline radiation from
unbalanced currents.
--
73, Cecil http://www.qsl.net/w5dxp


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On Sat, 14 May 2005 22:27:05 -0500, Cecil Moore
wrote:

Bob Miller wrote:
Cecil Moore wrote:
But with an antenna tuner, couldn't the end-fed Zepp be multi-band?
That's what I see on page 7-2 of the arrl antenna book.

You can certainly use an end-fed Zepp on other bands but
it won't be a Zepp on those other bands. The definition of
a Zepp is 1/2WL long end-fed with 1/4WL open-wire feedline.

What's the purpose of the 1/4 wave feedline wire that isn't attached
to the antenna? Is it kinda like a 1/4 wave elevated radial hoisted
into the air?

Bob
k5qwg

Bob Miller wrote:

Cecil Moore wrote:
You can certainly use an end-fed Zepp on other bands but
it won't be a Zepp on those other bands. The definition of
a Zepp is 1/2WL long end-fed with 1/4WL open-wire feedline.

What's the purpose of the 1/4 wave feedline wire that isn't attached
to the antenna? Is it kinda like a 1/4 wave elevated radial hoisted
into the air?

Assume the current in one wire into the 6000 ohm feedpoint is 0.1
amp and Z0 = 600 ohms. There's zero current flowing in the other
wire at the feedpoint.

The theory behind the Zepp is that there will be 1.0 amp in one
wire and 1.0 + 0.1 amp in the other wire at the transmitter. The
1/4WL section transforms the common-mode current problem from
100% at the feedpoint to about 10% at the transmitter.
--
73, Cecil http://www.qsl.net/w5dxp


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On Sun, 15 May 2005 12:28:19 -0500, "Joe S."
wrote:

Just put the goddam wire up in the air, tie some kind of feedline to it, run
it through the antenna tuner, tune for zereo reflected power and make
contacts. All else is bull****.


You have such a wonderful command of the English language ;-0

Joe S. wrote:
SNIPPED

Just put the goddam wire up in the air, tie some kind of feedline to it, run
it through the antenna tuner, tune for zereo reflected power and make
contacts. All else is bull****.

And engineers discussed this thread ad nausea!!

Put up an antenna, tune it, get on the air

Joe S. wrote:
Holy ****!!! I just read this entire thread and it has rapidly deteriorated
into a pile of nonsense. It's a Zepp on one band but not on another but
then it's a windom no it's not yes it is why not becasue yadda yadda.

Having a hard time keeping up?


Remember this: Engineers designed the Titanic. Engineers also designed the
sky bridge at the Kansas City Raddison and engineeers desigend the roof of
the Hartford Civic Center. And engineers design antennas.

Yeah, they do. And it's in fully understanding what is happening that
avoids disasters too. It's okay, you're special too.


Just put the goddam wire up in the air, tie some kind of feedline to it, run
it through the antenna tuner, tune for zereo reflected power and make
contacts. All else is bull****.


Or, in your case, just order your antenna from a vendor in the back of
QST and hang it in the back yard, jump on 75 meters and make farting
noises all night with your drunken buddies.

"I don't care how it works, just as long as it works". Which is fine,
but don't denegrate others because they want to discuss it. Don't like
it, ignore the thread.

HTH