Yuri, to be perfectly consistent, you would need to change all your
standing-wave antennas to traveling-wave antennas. I've got some
non-inductive terminating resistors for sale at the right price. :-)
--
73, Cecil http://www.qsl.net/w5dxp



Well, I've been thinking on those sleepless nights, how to turn standing wave
Yagis or Quads into traveling wave ones, with no back lobes. Got recipe? I've
got resistors.

Yuri

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



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Reg finally figured it out:

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.

Thank goodness we have your formulas, failproof programs and variety of
speculations. Gentlemen, case is solved, closed. We can't measure it, we are
all bunch of dumb delusional morons with faulty instruments who don't know how
to use them. Current must be the same in the coil according to Rauch, Kirchoff,
Ohm, Reg. So now make your antennas out of coils, you will have constant
current radiator tip to tip with 300% efficiency and you can throw your
instruments away. Reg has the formula for it, use it!

Seriously, I thank you Cecil, Fred and few others who enlightened our case,
that's what I was hoping for and found it here. It will be the springboard for
further development, it already gave me some ideas how to improve efficiency of
loaded aerials. The others from the flat earth society showed their colors and
they ain't pretty. Just like democRATs, when they are deficient in arguments
they triviliarize and ridicule.
We are planning mobile antenna shootout here on east coast in the spring, so
get your wares ready and see who is da king koil.

Yuri, da BU/m

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?


What was he measuring, where was the coil?
W9UCW used 100 mA at the bottom, I doubt that this would "cook" the coil. You
see the pictures, they are good quality coils and he use two meters and
flippped the coil to eliminate possible error as described here.

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.


Again, put on the fricken Hustler 80m resonator, feed it 100W and feel it! No
meters, no hokus pokus, just "naked" antenna.


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


One insufficiently described measurement is enough to throw rest out of the
window? W9UCW has shown data from various measurements and positions of the
coil (pictures how it was done) and W5DXP backed it up with explanation of
reflected wave and simulation and comparison with loading stub. It came out,
this is the ned. If you choose not to believe, its a free country :-)

Yuri

More pudding!

I added picture of current distribution when using inductance in the form of
loading stub as described earlier and from Eznec file supplied by Cecil. It is
at the end of the article at

http://www.k3bu.us/loadingcoils.htm

It shows the jump accross the stub, but when replaced by lumped inductor, the
Eznec shows constant current accross the coil.

Yuri

Yuri Blanarovich wrote:
Current must be the same in the coil according to Rauch, Kirchoff,
Ohm, Reg.

Kirchhoff and Ohm were not wrong. For a lossless coil, the forward current
magnitude must be the same in the coil and the reflected current magnitude
must be the same in the coil. But the net current is the sum of those two
component waves which have phase angles rotating in opposite directions.
The basic problem is using lumped circuit calculations for a distributed
network problem, a well known no-no.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

I haven't had the time to participate in this, but in a brief look, it
looks pretty silly. Of course EZNEC shows no current difference across a
load. The EZNEC model of a load has zero length, so the current at both
terminals has to be the same. You will see a current change over the
length of a model of a conductor, because it does have length. The coil
in the web site pictures certainly has length, so why should you be
surprised to find a current change over its length? Did the experimenter
perhaps do the same test with the meters placed the same distance apart
with just a conductor in between? Would there be some great revelation
in finding that the current was different at the two points?

I was intrigued by the claim that a toroid measured significantly
different from one end to the other. I wonder if the tester tried
reversing the meters to verify that he got the same reading in both
cases. If he did, I'd be interested in learning more details.

Unfortunately, the main objective of the web site seems to be to insult
Tom, W8JI, rather than to be objective. So in my mind that leaves the
possibility open that the experimenter is more interested in finding
evidence that would disprove Tom than in presenting carefully measured
and objective data.

Roy Lewallen, W7EL

Yuri Blanarovich wrote:
More pudding!

I added picture of current distribution when using inductance in the form of
loading stub as described earlier and from Eznec file supplied by Cecil. It is
at the end of the article at

http://www.k3bu.us/loadingcoils.htm

It shows the jump accross the stub, but when replaced by lumped inductor, the
Eznec shows constant current accross the coil.

Yuri