[antennaware] note on a Hy-Gain beam
Thu, 16 Apr 1998 20:16:46 -0400 (EDT)
Glad to hear about the HyGain info although I haven't seen it yet. Once
these designs are produced and sold, it's usually pretty easy to "Reverse
Engineer" them and prove to yourself whether they are real or not! Aren't
modeling programs great?
Just to get the facts straight, if you want to see the whole story on how
the HyGain model 7031 Yagi came to be, read my articles "A High Gain Long
Yagi for 70-cm" in the Lunar Letter Magazine, June/July issue 1983 and the
follow up article, "A high Gain 70-CM Yagi", in Ham Radio, December 1986.
HyGain even sent me their first sample of the 7031 as a thank you for
publishing the design that they copied from my article.
>For those interested in UHF beams, you may wish to model the 7031--an
>outstanding design at 19.6 dBi gain and 31 dB F-B on a boom under 24'
>long for a 50-ohm feed.
Yes, it's a versatile antenna design. I've made many shorter versions by
chopping the same antenna as you mentioned as well as an extended higher
gain 36 element version. I've also have a modified 31 element version that
is 50 Ohms direct feed with the same gain!
>If you need less gain (about 3.25 dB less) and can live with only 24.2 dB
>F-B, try modeling only the first 16 elements (from the reflector forward).
>They fit on a 10' boom and provide an even more perfect 50-ohm match--at
>least in the NEC-4 model. Beam width also increases from 20 degrees for
>the long version to 28 degrees for the "short" model.
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