Current through coils
 

wrote:
how much will you pay me for putting up with you?

How much do you need to be paid to discuss technical
issues on a technical newsgroup?
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Reg Edwards wrote:
Therefore Seconds Delay = Coil Length in metres / Velocity.

So what is it for a 25 turn coil, 12 inches long,
6 inches in diameter, made from #16 wire? EZNEC
says it depends upon the frequency.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

On Mon, 27 Mar 2006 17:17:04 GMT, Cecil Moore
wrote:
How much do you need to be paid
This was already asked and answered. Must be the gringo form of
bartering a deal.

No wonder the immigration problem has never gone away with the
Republicans in charge. "How much would you pay for a tall fence 3000
miles long?" If its built by the Army Corps of Engineers to Katrina
standards?

Current through coils
 

Cecil Moore wrote:
John Popelish wrote:

Cecil Moore wrote:

Everything about RMS standing wave current can be understood simply by
superposing the RMS values of forward and reflected current.


Boing!

You might want to think about that sentence for a while.


Let me rephrase. Everything about RMS standing wave
current can be understood simply by superposing the
values of the forward and reflected current phasors
whose phasor length is (usually) represented by their
RMS values.

Better.

As I said, earlier, This thread has drawn me back to re-reading "Zen
and the Art of Motorcycle Maintenance". If you haven't read it, I
highly recommend it.

Here is a passage that jumped out at me, last night.

"The real purpose of scientific method is to make sure
Nature hasn't misled you into thinking you know something
you don't actually know. There's not a mechanic or scientist
or technician alive who hasn't suffered from that one
so much that he's not instinctively on guard.
That's the main reason why so much scientific and mechanical
information sounds so dull and so cautious.
If you get careless or go romanticizing scientific information,
giving it a flourish here and there, Nature will soon
make a complete fool out of you. It does it often enough anyway
even when you don't give it opportunities.
One must be extremely careful and rigidly logical
when dealing with Natu one logical slip and an entire
scientific edifice comes tumbling down. One false deduction
about the machine and you can get hung up indefinitely."

More at:
http://www.public.iastate.edu/~stuga...ntena nce.pdf

Current through coils
 

John Popelish wrote:
"The real purpose of scientific method is to make sure
Nature hasn't misled you into thinking you know something
you don't actually know."

Hmmmm, anyone we know?
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Cecil Moore wrote:
John Popelish wrote:

"The real purpose of scientific method is to make sure
Nature hasn't misled you into thinking you know something
you don't actually know."


Hmmmm, anyone we know?

Potentially everyone you know.

Oh wait...

We really don't know anyone.
We only pretend we do.

Current through coils
 

So what is it for a 25 turn coil, 12 inches long,
6 inches in diameter, made from #16 wire? EZNEC
says it depends upon the frequency.
--
73, Cecil
==================================

Use both programs and compare the results.

Make the coil 1 metre long, 500 turns, and diameter 25.4 mm (1 inch).
Give the programs something to get their teeth into.

How does EZNEC make its calculations? If you don't know you are
placing your faith in a mirage.
----
Reg.

Current through coils
 

On Mon, 27 Mar 2006 18:58:16 +0100, "Reg Edwards"
wrote:

If you don't know you are placing your faith in a mirage.

Now there's a commendation for your own work. No wonder we don't see
any correspondence from you with actual values for the coils offered.

Lords Plushbottom and Kelvinator might let you serve in the black
gang, moving coal on one of those transatlantic cable layers - but
they certainly wouldn't expect a practical answer to:

"How many shovels full today Reggie?"

"If your lordships will forgive me, but you can find out by
downloading my unzipped SHUVFULL.EXE and entering many fascinating
variables."

"I say, Plushbottom old son, we must ask the Boatswain to check
the coal bunkers for hidden bottles of Sack."

Who would've guessed that the comedic possibilities still lingered
after 600 postings. ;-)

Current through coils
 

Reg Edwards wrote:
Please note that nobody has made valid measurements of the delay
through a loading coil. The closest thing to a valid measurement
presented thus far is the EZNEC simulation on my web page:

=======================================
Dear Antagonists,

Why go to the great hazardous trouble of measuring it when it can
easily be calculated from physical dimensions of the coil.

Velocity V = 1 / Sqrt( L * C ) metres per second

where L and C are henrys and farads per metre.

Therefore Seconds Delay = Coil Length in metres / Velocity.

OK, I admit it's an approximation because coil turns couple one part
of the 'line' to another a short distance away. It is not unconnected
with proximity effect. This does not occur in a normal transmission
line. But the approximation holds.

See and amuse yourselves with program TRANCOIL.

It's hard to tell from this, but are you still claiming that the
end-to-end C of an inductor is the C of an equivalent transmission line?
Or even an approximation? Does your program assume this?

Roy Lewallen, W7EL

Current through coils
 

Reg Edwards wrote:
. . .

How does EZNEC make its calculations? If you don't know you are
placing your faith in a mirage.

A bit more than a mirage -- you're placing your faith in a program
(NEC-2) which has been in daily use by hundreds to thousands for nearly
30 years, and has been used for designing countless antennas, several of
which you almost certainly use daily.

But anyone interested in knowing how EZNEC does its calculations can get
a highly detailed answer from the NEC-2 manual, available free at
http://www.si-list.org/NEC_Archives/nec2prt1.pdf. Or, if interested in
the general method (method of moments), there's a very good and easy to
understand explanation in the second and later editions of Kraus'
_Antennas_. I'm sure there are some good (and undoubtedly also bad)
explanations of the moment method on the web, also.

Roy Lewallen, W7EL