N6RY and I designed, built and tested a truly broadband 80 meter dipole
that offers SWR of 1.5:1 or better across 99% of the entire band, with
the 1% being at 1.6:1 and at the absolute top of the band. We wrote an
article on the antenna that had been accepted by CQ Magazine for
publication but got "preempted" when QST, by sheer coincidence, ran an
article on a very similar design while the CQ editing process was under way.
If anyone would like a copy of the article and all its graphs, photos,
etc, let me know at w7zz@arrl.net and I'll set up a Dropbox file and
send you a link to it. Not only does it go over the design of the
antenna, it covers how to build it so that it will last, how to match
the antenna using a simple series match made from 75 ohm coax and how to
keep the feedline from radiating using a choke (including the design of
the choke). I can also provide the actual EZNEC files for versions of
this antenna on all of the low bands, 160-10m. These models will not
run on the free version of EZNEC that comes with the ARRL Antenna Bookas
the models have too many "segments." They require the full version (but
not professional version) of EZNEC 4.0 or 5.0.
This antenna has been up and in operation at my station for a couple
years nowat 80 feet. It is a fantastic performer. The EZNEC files model
a refined version at 80' (mine was an early beta version but it works so
well I never bothered to build our final version), 60' and at 35'. The
dimensions of the antenna and the series match change at each height. I
also have a 40m version up with even better results in terms of both SWR
and performance. It is at about 80 feet also (with the models at 35, 60
and 80feet). I have had up a 20m version which also performed as
predicted by EZNEC. We designed a 160 versionthat, while much better
than a regular dipole, isn't anywhere near as good as the 80-10m versions.
Let me know if you're interested. 73, W7ZZ
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