On 12/12/13 10:00 PM, Peter Voelpel wrote:
Antennas with the narrow spaced first directors were standard many years
before DL6WU published that for ham radio antennas.
I installed TV VHF antennas by Kathrein, Hirschmann and Wisi with closed
spaced first directors at privat customers already in the years 1961-1963
when I learned to become a Radio+TV technician.
All antennas were designed with folded dipoles, either direct fed with 240
ohm cable or 60 ohm coax + balun.
And there's probably some IRE or IEE papers out there, or somebody's
master's thesis describing it, or presenting some sort of analysis.
There's an awful lot of fooling around with HF antennas in the 40s, 50s,
and 60s. Lots of independent discovery, especially as people started to
apply analytical techniques to the designs and try different things.
The desire for wide bandwidth or loose manufacturing tolerances is
universal. But much of this stuff isn't readily accessible. My father's
masters thesis (UW in the 50s) was on some sort of multi element wire
yagi (for ham bands), but it's not online and googleable: Heck, I
haven't seen a copy of it in at least 30-40 years, and I'll bet he
hasn't seen it either. There's probably a copy on microfilm somewhere.
SO it could really be that WA3FET was the one who popularized it in the
ham community. He was an "early adopter" of numerical modeling, and
that's really how you get "unusual" antenna designs to work, rather than
cut and try. There's just too many parameters to optimize and
particularly in a Yagi with a lot of elements, the analytical
expressions for mutual coupling, don't work as well when things are
close together. If you build a series of test articles and measure
them, it's not clear that the data you get will tell you which direction
you need to move in terms of the design. It's not like trimming the
ends of a dipole, where you can do the first 2 or 3 cuts and make a
pretty good estimate from the measurements as to where the "final cut"
needs to be.
The easiest way to find out is to ask Jim Breakall where the idea came from.
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