Whenever I've thought I had stumbled onto a "breakthrough" in rf design,
whether it be an antenna or a circuit, I have later found my measurement
techniques to be lacking. Garbage In ... Garbage Out.
Proper RF measurement is a science itself. If you can't trust your
measurements, the results are worthless.
Whether it's magic antennas, cold fusion or room-temperature superconductors...
plenty of institutions of higher learning have been embarrassed by outlandish
claims.
If URI's claims are proven false, the devil will be in the measurement
techniques.
Larry N8LP
----- Original Message -----
From: Tom Rauch
To: Jon, W4ZW ; 'Towertalk'
Sent: Tuesday, June 08, 2004 7:29 AM
Subject: Re: [TowerTalk] URI magic antennas
> *I agree that the track record for recently announced
amazing
> *new antenna inventions has been poor, but are you really
> *asserting that there will be no new antenna designs from
here on?
> *
>
> Dave strikes a familiar chord.
He sure does. There's nothing wrong with hoping for magic.
Unfortunately most people never think in detail about "new
inventions". There hasn't been any "new invention" that has
re-written past rules. The only real changes are in how old
technology is applied or how methods of using the technology
are improved.
For example, mutual coupling effects and radiation theory
wasn't rewritten by the Yagi....and if Uda and Yagi didn't
"invent" the Yagi ten's of thousands of others could have
just from textbook work. Uda didn't create anything new, he
just filled a need. Same for the Quad. It is really just two
end-loaded 1/4 wl long element Yagi's stacked 1/4 wl apart.
The basic physics have remained unchanged for many hundreds
of years, they have only be defined by more and more
detailed rules. Inventions are really just filling a new
need by applying old rules.
21 feet of wire in a two-foot box at BEST has all the loss
resistance of that 21 feet of wire and all the radiation
ability of a two-foot area. Unfortunately there is no way
around that, and there never will be. We could minimize
resistance with better conductors or increase ampere-feet by
making current uniform, but beyond that we are stuck with
the basic rules.
That's why all this nonsense...the Fractals, CFA's, CTHA's,
DDRR's, Isopoles, E-H antenna's, etc.....all turn out to be
efficiency duds. Analyzing radiation from a piece of wire
isn't a complex or esoteric science. You make the thing
smaller, and current goes up for a given amount of radiated
power. When current goes up, I squared R losses go up.
It's always worked that way in the past, it will always work
that way in the future.
73 Tom
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