[TenTec] Re: Rudimentary SWR question...

[Bill Fuqua]

I see now that the problem is that some of you are caught in an old on 
going argument between non-resonant antennas and resonant antennas.  By the 
way I have used  "wires" and "AO" for years. But  not recently because I 
lost the key and spare and software when my old computer died. And nothing 
I modeled contradicts what I am saying. But supports it.

Look here. If you can load the antenna, and the energy is not going into 
resistive, dielectric loss or any other kind of loss then it must be 
radiating it.  Does not matter if the antenna is short, long or resonant. 
That energy has to go some where (conservation of energy). If not into heat 
or work into the sky as radio waves.

My point is if you use a non-resonant antenna and match it to your radio 
you then have a resonant antenna system.  Equilibrium means energy in 
equals energy out.  Resonance is a way of doing this.

These programs assume that the modeled antenna has a fixed amount of power 
going into them regardless of the impedance.
The program provides the feed point impedance which you must match to 
transfer power to the antenna. The match is called a conjugate match. By 
doing so you have created the electrical condition for resonance. The 
capacitive reactance and inductive reactance are equal. So now your antenna 
system (antenna, transmission line, tuner etc) is resonant.

What is it about resonance, conservation of energy, equilibrium and Q that 
makes this discussion do difficult.

73
Bill wa4lav



At 08:38 AM 10/21/2003 -0500, you wrote:
> >In fact, why don't *you* invest in Roy's program and judge the validity of
> >these - to you - debatable matters for yourself. Might be some surprises in
> >there . . . give you something to do during the coming sunspot lull.
>
> >I really do have a pretty good idea how those wires in the trees work,
> >Billy, and mine work very well.
>
>Come on George, What ... Can't stand the heat?  B-)
>
>Before you play the dodge card here, look again at YOUR WORDS:
>
>"It turns out that any wire antenna that is at least 0.3 wavelengths long
>on a given band will radiate a signal whose strength is almost immeasurably
>different from that of a half-wave dipole."
>
>ANY wire antenna?  ANY? That a VERY broad sweeping statement to make.
>
>You are telling me that a vertical oriented 0.3w wire hung in a tree, and
>fed at it's base ... or even in it's center via a tuner ... will "radiate 
>a signal
>whose strength is almost immeasureably different from that of a half-wave
>dipole?" ... YOU need to go back to the books, and rethink that statement.
>
>Or let's say a 0.3w wire antenna, fed at the center, horizontal at 0.5w above
>ground, compared with a 0.5w wire antenna, at 1.0w above ground ... the
>signal radiated may NOT be the same for any given wave angle. The 0.5w will
>have nulls where the 1.0w antenna has peaks ... NOW defend you statement,
>as Roy, LB, etc. ... and "the books" all support what I have just typed ...
>
>Instead if you want to be specific as to comparing say one 0.3w antenna, 
>fed in
>the center mounted at 0.8234w high against one 0.5w <half-wave dipole>
>also at 0.8234w high ... your statement can be accurate. The only loss will be
>that of the loading method used, which if the Q is high, should be low.
>
>Ah, but that is NOT what you posted ... you said "ANY" ... now didn't you?
>And that's how the "old wives tales" get started, by statements such as 
>that ...
>
>Actually I have been using Roy's and others programs since day one, and my
>point was your broad sweeping statements ... such as"work very well" is a 
>very
>vague opinion ... I'll wrap this one up, by agreeing with your own words 
>stated
>accurately above ... "debatable matters" ... only if you ignore the basic 
>rules as
>many have posted here over a long period of time, and easily found confirmed
>in the various textbooks of amateur and academic nature.
>
>73 Billy AA4NU  ... who hopes to be working on his 160m 4x array during 
>the next sunspot lull.
>
>
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