Yuri Blanarovich wrote:
Thank you Cecil and Fred!
(Where is Roy? We could use expert guidance in modeling the case.)

I sent Roy a copy of the EZNEC file that I sent to you. Anyone else
who wants a copy of those files, send me an email.

I will post your comments on eHam.net.

Which forum/topic?
--
73, Cecil, W5DXP

I sent Roy a copy of the EZNEC file that I sent to you. Anyone else
who wants a copy of those files, send me an email.


I didn't get it, for direct mail take noSaddam out :-)

I will post your comments on eHam.net.

Which forum/topic?
--
73, Cecil, W5DXP

The article and follow up comments are at:

http://www.eham.net/articles/6512

Yuri, www.K3BU.us

Yuri Blanarovich wrote:
The article and follow up comments are at:

http://www.eham.net/articles/6512

Egads, did I get the last word? (so far) That's proof of action
at a distance. I'm a thorn in the side of hams who are not even
on the same newsgroup as I. :-)
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore wrote in message ...
Yuri Blanarovich wrote:
The article and follow up comments are at:

http://www.eham.net/articles/6512

Egads, did I get the last word? (so far) That's proof of action
at a distance. I'm a thorn in the side of hams who are not even
on the same newsgroup as I. :-)

Dunno...I finally got up enuff courage to wade thru a bunch of that
myself. Both had some decent points..But....Just using my built in
"BS" filter only, which rarely seems to fails me, and ignoring all
other influences, I still have to side with Tom. I still think the
current is fairly constant. But not perfectly so, and can vary due to
the antenna and it's mount, etc. I guess I'll just wait until the
smoke clears to see how far off I am. This will be a good test of my
filter unit. As far as who wins, I could care less. Nothing
personal either way...But I have learned never to ignore my BS filter,
so I'm going with it. MK

But....Just using my built in
"BS" filter only, which rarely seems to fails me, and ignoring all
other influences, I still have to side with Tom. I still think the
current is fairly constant.

Nothing
personal either way...But I have learned never to ignore my BS filter,
so I'm going with it. MK


Same here,
did your filter filtered out W5DXP pudding? The "theoretical" proof is right
there. Or are you drinking the same coolaide as Tom? :-)

Yuri

Reality vs. Speculations? Duuuh?

Yuri Blanarovich wrote:
Same here,
did your filter filtered out W5DXP pudding? The "theoretical" proof is right
there. Or are you drinking the same coolaide as Tom? :-)

Yuri, my latest posting sheds more light. Apparently, W8JI doesn't
realize that there are two superposing currents phasor-adding together
to get the net current and the phase distribution between those two
current waves are opposite because they are traveling in opposite
directions. This is a characteristic of standing-wave antennas.

See what happens when one tries to ignore the component waves?

Because the two currents are traveling in opposite directions, any phase
delay through the coil shifts the phase of the two currents IN OPPOSITE
DIRECTIONS. Thus the total relative phase shift effect through a 10 degree
coil is 20 degrees.
--
73, Cecil http://www.qsl.net/w5dxp



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oSaddam (Yuri Blanarovich) wrote in message ...
But....Just using my built in
"BS" filter only, which rarely seems to fails me, and ignoring all
other influences, I still have to side with Tom. I still think the
current is fairly constant.

Nothing
personal either way...But I have learned never to ignore my BS filter,
so I'm going with it. MK


Same here,
did your filter filtered out W5DXP pudding? The "theoretical" proof is right
there. Or are you drinking the same coolaide as Tom? :-)

Yuri

Reality vs. Speculations? Duuuh?''

Oh, purely speculation on my part. I have no easy way of really
knowing the reality. There is a small part that keeps bugging me, but
I'd have to see for sure where he is measuring the currents. I missed
the pix on the site. I'll assume for now he measured at each end of
the coil, pretty much at the connection to the mast or whip. The part
the bugs me is a possible stunting of the current at the top of the
coil due to the capacitance it is looking at, at the end of the coil.
To my thinking, once you leave the coil, even right at the end, you
should see a reduction of current, compared to say even a turn or two
from the top of the coil. I'm just wondering if this may be giving a
false indication of the true currents within the coil,if he is
measuring slightly outside of the coil. I'd be more satisfied if he
could measure a few turns from each end "using a large, many turns,
coil for 80 or 160" to get a general view within the windings
themselves. But I realize this could be very difficult. You all may be
totally correct. I'd just like to be a little better convinced before
I totally agree. I expect a slight decrease in current at the top vs
bottom. But I don't expect it to be large. I also don't expect the
bottom of the coil to be "hot", with a radical current taper on the
upper windings. The main thing I see to causing a reduction of
current , is the stinger on top of the coil. "capacitance" I wonder if
he is seeing the effects of that capacitance in his lower measurement?
Only the shadow knows for sure....:/
As far as the reverse currents Cecil mentions, I'd have to ponder that
a while.
Seems to me that could wildly vary from antenna to antenna depending
on height, coil positions, any top loading, etc..Although it looks
good on paper, I smell a hook. So I'd have to think about that more.
BTW, this amount of current in the coil, is something I've also
thought about myself. I've just come to the "different" conclusion
it's fairly constant through the coil. I could always be wrong.
Wouldn't be the first time.. But I need to see/hear a bit more to be
convinced. MK

Radio amateurs and just as many professionals suffer from delusions of
accuracy where RF measurements are concerned.

Especially HF current and power measurememts.

Far too much importance is attached to names like GR and HP and Fluke rather
than their own abilitity to assess and sum the accumulation of measuring
errors.

--
=======================
Regards from Reg, G4FGQ
For Free Radio Design Software
go to http://www.g4fgq.com
=======================
"Mark Keith" wrote in message
om...
oSaddam (Yuri Blanarovich) wrote in message
...
But....Just using my built in
"BS" filter only, which rarely seems to fails me, and ignoring all
other influences, I still have to side with Tom. I still think the
current is fairly constant.

Nothing
personal either way...But I have learned never to ignore my BS filter,
so I'm going with it. MK


Same here,
did your filter filtered out W5DXP pudding? The "theoretical" proof is
right
there. Or are you drinking the same coolaide as Tom? :-)

Yuri

Reality vs. Speculations? Duuuh?''

Oh, purely speculation on my part. I have no easy way of really
knowing the reality. There is a small part that keeps bugging me, but
I'd have to see for sure where he is measuring the currents. I missed
the pix on the site. I'll assume for now he measured at each end of
the coil, pretty much at the connection to the mast or whip. The part
the bugs me is a possible stunting of the current at the top of the
coil due to the capacitance it is looking at, at the end of the coil.
To my thinking, once you leave the coil, even right at the end, you
should see a reduction of current, compared to say even a turn or two
from the top of the coil. I'm just wondering if this may be giving a
false indication of the true currents within the coil,if he is
measuring slightly outside of the coil. I'd be more satisfied if he
could measure a few turns from each end "using a large, many turns,
coil for 80 or 160" to get a general view within the windings
themselves. But I realize this could be very difficult. You all may be
totally correct. I'd just like to be a little better convinced before
I totally agree. I expect a slight decrease in current at the top vs
bottom. But I don't expect it to be large. I also don't expect the
bottom of the coil to be "hot", with a radical current taper on the
upper windings. The main thing I see to causing a reduction of
current , is the stinger on top of the coil. "capacitance" I wonder if
he is seeing the effects of that capacitance in his lower measurement?
Only the shadow knows for sure....:/
As far as the reverse currents Cecil mentions, I'd have to ponder that
a while.
Seems to me that could wildly vary from antenna to antenna depending
on height, coil positions, any top loading, etc..Although it looks
good on paper, I smell a hook. So I'd have to think about that more.
BTW, this amount of current in the coil, is something I've also
thought about myself. I've just come to the "different" conclusion
it's fairly constant through the coil. I could always be wrong.
Wouldn't be the first time.. But I need to see/hear a bit more to be
convinced. MK

Mark Keith wrote:
As far as the reverse currents Cecil mentions, I'd have to ponder that
a while.

While you are pondering, here is a quote from _Antenna_Theory_, by Balanis.

"Standing wave antennas, such as the dipole, can be analyzed as traveling
wave antennas with waves propagating in opposite directions (forward and
backward) and represented by traveling wave currents 'If' and 'Ib' in
Figure 10.1(a)."

Standing wave antennas necessarily have standing waves caused by forward
waves and reflected waves. Analyze any coil subjected to forward current
and reflected current and you will be forced to agree that the current
at one end of the coil is not the same as the current at the other end
of the coil. W8JI is thinking lumped circuits when he should be thinking
distributed networks. The phase shift through the coil changes the
phase relationship between the forward current and reflected current, so
of course, their superposed value will be different at each end of the coil.
--
73, Cecil http://www.qsl.net/w5dxp



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oSaddam (Yuri Blanarovich) wrote in message ...
But....Just using my built in
"BS" filter only, which rarely seems to fails me, and ignoring all
other influences, I still have to side with Tom. I still think the
current is fairly constant.

Nothing
personal either way...But I have learned never to ignore my BS filter,
so I'm going with it. MK


Same here,
did your filter filtered out W5DXP pudding? The "theoretical" proof is right
there. Or are you drinking the same coolaide as Tom? :-)

Yuri

Reality vs. Speculations? Duuuh?

I found this comment interesting. Note this is from one that actually
has tried measuring the current in coils. This was from the site you
mention...

quote
I once had an occasion where the bottom of a coil did get warm, while
the top did not. Yet my RF ammeters showed the same current on both
ends. What was going on?

I ultimately determined that the soldered connection from the coil to
the lower antenna mast (for experimentation, it was copper) was adding
some undesireable resistance. Solder is not a particularly good
conductor of electricity. I copper-plated over the solder joint. Not
only did the bottom section of the coil no longer get warm, but the
two RF ammeters both showed about 20% more current flowing in the
antenna. And my far-field instruments showed a 1.5dB increase in field
strength.

unquote

This is one example of being fooled....If you took coil temp at face
value, you would think the current taper was quite steep, judging from
the temp's of the windings. But nope...A resistive connection seemed
to be the culprit. Note that his meters showed the same current on
both ends. :/ You can see why I'm afraid of that "hook" that usually
is lurking ready to bite at a moments notice.
Don't worry, if you are right, it will come out in the end. But that
hook...Ouch.. MK