Topband: Re: 160 Loaded Vertical Antennas (Barry, W9UCW)

[David Sinclair]

From:           	"Dennis O'Connor" <doconnor at chartermi.net>
To:             	<topband at contesting.com>
Subject:        	Topband: Re: 160 Loaded Vertical Antennas (Barry, W9UCW)
Date sent:      	Fri, 16 May 2003 16:39:11 -0400

> Barry,
> Given your premise that the observed current taper equals radiation, and assuming that 1500 watts into the average antenna coil neither melts it, nor radiates light, then it must be radiated as baseband... Correct?
> 
> So, as part of your article I would expect (if I were a referee reviewing your paper) that you would also remove the vertical radiator portions above and below the coil, replace them with a parallel capacitor across the coil and measure the current taper and the radiated field strength... If 
your premise is that the EM field contained in an inductor is not as conserved as previously thought, then a parallel tuned circuit, minus the radiating whip, should result in radiation consistent with the observed current taper minus heating losses...  Correct?
> 
> The other item I would consider essential, as a referee, would be the placement of the tuned coil into a calorimeter bomb, and a measurement of the developed heat, so that we can quantify how much radiation is baseband, and how much is IR loss..  
> Assuming I understand what has been said...
> 
> Be aware that a published article/book challenging what is considered to be established physics. is tantamount to a double dare...  Expect to be thumped roundly about the head and shoulders by critics...
>  
> Cheers  ...  Denny

Hi, Denny-
Easy to propose, harder to dispose- how about helping Barry to
design such a calorimeter test that could reasonably be expected
to subject that coil to the same conditions it sees aloft as part of
a vertical HF radiator? It seems quite unfair to me when you
characterize conditions as being "1500 watts into the...coil".
We have not yet established that it's even 1500 watts into the
antenna feedpoint. After all, we are only dealing with anecdotal
evidence at times, or inferences drawn from their data which
may or may not be valid (the inferences). They performed their
tests at relatively low power levels. Mr. Heisenberg likely sleeps
soundly in his grave tonight, laughs at us in our restless dreams,
and rolls not a bit. He might have a few sarcastic comments 
about that proposed calorimeter test, however.

It seems to me that you may have proposed a test whose
results could prove meaningless, or which might be impractical
to easily implement in any case. Can you please elaborate and
justify your test's relevance? How are you going to simulate,
using lumped constants, all those many and finely distributed
real-world reactances associated with the coil in place,
performing its real-world function, however inefficiently?
Inquiring minds want to know. BTW I certainly doubt that coil is
lossless. All that has really been implied, as I understand it, is
that such coils can perform their intended functions at
relatively high amateur power levels without failing
catastrophically for whatever reason, and that most decent
amateur loading coils must incur, for the most part, 'reasonably'
low losses, according to the data collected. What constitutes
"reasonable" would of course be very much open to debate.
Personally, I still favor using capacitance hats exclusively to
obtain antenna resonance, wherever possible, but mobile
whips for 160m unfortunately do not fit into that scenario
very well.

I was quite surprised when it developed in this thread that
Barry and his group had had access to such highly
miniaturized thermocouple RF ammeters. Wow! I'd never
heard about those gadgets before. Perhaps Mr. Heisenberg
might be willing to sign off on that method of instrumenting
the coils. Pretty slick!
  
The implications of the experiments done on 80 and 20, as I
understand them, are that most coils' losses must be at least
'tolerably' low, as their claimed differences amounted to no
more than ~0.3 dB, max. If their reasoning was incorrect, then
what was defective with their method that would invalidate
their results and conclusions?   73, David K3KY

"Back off man- I'm a scientist!"
(Dan Ackroyd in "Ghost Busters")

"Is this beating and clubbing a part of the dance?"
(Firesign Theatre in "Everything You Know Is Wrong")
>
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