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.
--
73, Cecil http://www.qsl.net/w5dxp


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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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