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Old August 26th 04, 05:29 AM
Roy Lewallen
 
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Do you have a quote showing exactly what Tom said, in context?

Roy Lewallen, W7EL

Richard Harrison wrote:

Art Unwin wrote:
"What did he say that was wrong?"

Recently Tom argued with Yuri that loading coils must have the same
current in and out. Circuit theory does not directly apply in all cases
due to the possibility of a reflected wave on the coil and due to
radiation from a loading coil.

Did Tom ever admit that it`s possible that current into one end of the
coil does not necessarily equal the current at its other end?

Best regards, Richard Harrison, KB5WZI

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Old August 26th 04, 05:39 AM
 
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"Richard Harrison" wrote in message
...
Art Unwin wrote:
"What did he say that was wrong?"



I said more than that!, Ae you cherry picking again?
You did not prove your case against Tom in your allegation, period
Now you scurried away to something else without justifying that your
original
is correct and Tom is wrong!
Climbing towers to tighten nuts under direction does
not make you an antenna expert where as Tom has proved himself
amoung the amateur community time over time.



Recently Tom argued with Yuri that loading coils must have the same
current in and out. Circuit theory does not directly apply in all cases
due to the possibility of a reflected wave on the coil and due to
radiation from a loading coil.

Did Tom ever admit that it`s possible that current into one end of the
coil does not necessarily equal the current at its other end?




I haven't seen a posting from Tom on this newsgroup for a very long time.
Did you confront him to his face about this or are you talking about him in
his absence?
Go to EHAM and confront him like a man especially if this original
confrontation
occured else where. Ifyou have a problem with some one about something then
talk to him directly
instead of throwing mud when he isn't looking. There have been many
statements made about Tom lately
that I can't verify in RRAA records so why are you bringing mud to this
table especially
when the target is not here to defend himself and especially if your
charges are scurrilous
and without depth







Art

Best regards, Richard Harrison, KB5WZI



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Old August 26th 04, 06:11 AM
Roy Lewallen
 
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I have a great deal of respect for Tom, W8JI. In fact, there are few
people I respect as much. I regard him as being exceptionally honest,
very analytical, and always seeking to find the truth and increase his
knowledge. Whenever his view of how things work have been shown to be
wrong, I've found him to readily accept the corrected view, and be
grateful of the opportunity to learn something new. I've also learned
from him on more than one occasion. One notable case is the idea of
using a balun at the input of a tuner to improve the balun's balancing
properties. I had believed it to work, but he showed me where I was
wrong, giving me the opportunity to increase my knowledge.

I find it contemptable and cowardly to attack him -- or anyone -- in a
forum where he's not a participant and isn't present to correct
misquotes, quotes taken out of context, and otherwise respond and defend
himself. People doing so should instead sign onto one of the election
campaigns or go on AM talk radio, where such gutless, dishonest, and
mean-spirited activity is the accepted norm.

I believe the Russians have a word for this kind of cowardly and
"uncultured" activity -- something like "nyekulturny". Maybe Yuri knows.

Roy Lewallen, W7EL
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Old August 26th 04, 06:39 AM
Cecil Moore
 
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Richard Harrison wrote:
Did Tom ever admit that it`s possible that current into one end of the
coil does not necessarily equal the current at its other end?


His own measurements proved that the currents at each end of
air-core loading coils are NOT equal.
--
73, Cecil http://www.qsl.net/w5dxp



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  #46   Report Post  
Old August 26th 04, 06:54 AM
Cecil Moore
 
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Roy Lewallen wrote:
Do you have a quote showing exactly what Tom said, in context?


Here's one from his web page:

"What determines current distribution in a loading coil? The capacitance
to the outside world and the impedance above the loading coil. The current
in any inductor would be equal at each end except for displacement currents,
which are "imaginary currents" that flow through capacitance."

He completely ignores the fact that, for a standing-wave antenna, the net
current is the superposed phasor sum of the forward current and reflected
current and whatever phase shift occurs through the coil is doubled because
those two currents are traveling in opposite directions.

He is thinking lumped circuit model when he should be using a distributed
network model. What he says is reasonably accurate for a traveling-wave
antenna but certainly not for a standing-wave antenna.

EZNEC clearly illustrates the difference in the currents when the coil is
modeled as a coil of wire segments and not as a lumped inductor. Anyone who
would like a copy of the EZNEC file need only request it.
--
73, Cecil http://www.qsl.net/w5dxp



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Old August 26th 04, 07:04 AM
Cecil Moore
 
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Roy Lewallen wrote:
One notable case is the idea of
using a balun at the input of a tuner to improve the balun's balancing
properties. I had believed it to work, but he showed me where I was
wrong, giving me the opportunity to increase my knowledge.


Over on eHam.net, he just admitted that a real world application
does not act like that perfect paper solution. He said:

"In real life, stray capacitances from the network to ground modify
the behavior of the system when the balun is moved ..."
--
73, Cecil http://www.qsl.net/w5dxp



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Old August 26th 04, 04:26 PM
Tom Donaly
 
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Cecil Moore wrote:
Roy Lewallen wrote:

Do you have a quote showing exactly what Tom said, in context?



Here's one from his web page:

"What determines current distribution in a loading coil? The capacitance
to the outside world and the impedance above the loading coil. The current
in any inductor would be equal at each end except for displacement
currents,
which are "imaginary currents" that flow through capacitance."

He completely ignores the fact that, for a standing-wave antenna, the net
current is the superposed phasor sum of the forward current and reflected
current and whatever phase shift occurs through the coil is doubled because
those two currents are traveling in opposite directions.

He is thinking lumped circuit model when he should be using a distributed
network model. What he says is reasonably accurate for a traveling-wave
antenna but certainly not for a standing-wave antenna.

EZNEC clearly illustrates the difference in the currents when the coil is
modeled as a coil of wire segments and not as a lumped inductor. Anyone who
would like a copy of the EZNEC file need only request it.
--
73, Cecil http://www.qsl.net/w5dxp



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Current waves can travel in two directions at the same time. Charge
can't. For a guy who doesn't seem to be able to make the distinction,
you don't have any business criticizing Tom Rauch's understanding of
the situation.
73,
Tom Donaly KA6RUH
  #49   Report Post  
Old August 26th 04, 06:18 PM
Richard Clark
 
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On Tue, 24 Aug 2004 00:54:10 GMT, Richard Clark
wrote:

Now, I know that such antennas are not designed to be transmit
antennas (and again, perhaps too short to boot); so I will leave that
to others to engage as a receive antenna if they doubt reciprocity (or
I will do that later this eve for them as I often have to).


Hi All,

I've repeated the models with longer runs: 1000 meters length @ 80M.

For transmits, the single wire over ground shows a gain of 0.42dBi at
10° but with a F/B of 16.4dB. EZNEC proclaims the model exhibits 17dB
loss.

For transmits, the double wire over ground shows a gain of 1.2dBi at
10° but with a F/B of 11.7dB. EZNEC proclaims the model exhibits 17dB
loss.

However, Beverages are not typically the first choice for
transmission, but rather reception. Does reciprocity hold? As no one
has offered to help the Little Red Hen, would they care to share in
the cake?

For the receive single wire Beverage @ 10° w/600 Ohm load
Total load power = 5.543E-07 watts

For the receive double wire Beverage @ 10° w/600 Ohm load
Total load power = 6.623E-07 watts

Now, if we compare the two receive loads we find they differ by .77dB
which is the same difference for the transmission models. By most
accounts, that means reciprocity prevails. By further accounts, that
means the double wire system is superior - if you want to lay out 1000
meters of wire for less than one dB (that pesky one dB value judgment
again).

By this point, what with all the trolling going on and so little
actual technical content, What was this all about?

73's
Richard Clark, KB7QHC
  #50   Report Post  
Old August 26th 04, 07:36 PM
Reg Edwards
 
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"Richard Clark" asked -

Does reciprocity hold?


-------------------------------------------

How dare you question it?
----
Punchinello.


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