[TowerTalk] re Twinlead zepp
RadioIR at charter.net
Sat Nov 5 14:55:14 EST 2005
I'm with the old school who calls a center fed antenna a dipole, and a
Zepp the same thing they used on Zepplins, and there is no such thing as
a center fed Zepp. Since I don't claim to be up on all the latest
terminology, I went to my ARRL Antenna books to see what is now being
used for antenna names. It may be that other groups have different
terms, so I just stayed with ham related sources. Here is what I found.
A dipole is a class of antennas with two poles, one on each side of
center, not necessarily resonant. This is a class, so modifier words are
needed to distinguish specific types of dipoles: center fed dipole,
center fed half wave dipole (also called a classic dipole), off-center
fed dipole, folded dipole, inverted vee dipole, trap dipole, etc.
An End Fed Zepp (or just Zepp) is the old Zepplin antenna.
A Double Extended Zepp has 0.64 wavelength wires on each side of the
center feed point.
The only mention of a center fed Zepp antenna in any of the ARRL books
was the comment that this was a misnomer. I did find an article written
by an ARRL staff member about a Center Fed Zepp, and he gave an example,
but not a definition. It was a dipole fed with ladder line. Cebik uses
the term but he doesn't define it either. He tends to use it as a
dipole fed with balanced line. I found several other reference to a
center fed Zepp, but no definitions. Many of the newer hams use this
term, but I don't think they know what it means either.
My opinion: Center Fed Zepp is a nice fancy name newer hams are picking
up and using, but no one knows for sure exactly what it is, or they have
their own definition which is not necessarily the same as that of
others. In my version of the definition, I would add that is has to be
pointed true north.
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