Ian White, G3SEK wrote:
Yes! That principle of impedance substitution is so simple, so
fundamental, some people never notice it's there at all.

And you would apparently like to pull the wool over the eyes of everyone
who notices that the definition of impedance has changed in the process.
Shame on you for that attempt at obfuscation!
--
73, Cecil http://www.qsl.net/w5dxp



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W5DXP wrote:
Ian White, G3SEK wrote:
Yes! That principle of impedance substitution is so simple, so
fundamental, some people never notice it's there at all.

And you would apparently like to pull the wool over the eyes of everyone
who notices that the definition of impedance has changed in the process.
Shame on you for that attempt at obfuscation!

You are using that principle of impedance substitution whenever you
calibrate your antenna impedance bridge using known values of resistORS,
capacitORS and inductORS.

Of course *you* are aware of the difference in what's connected to the
instrument - you have more information than it has. The only claim Bill
and I have been making is that you cannot tell the difference from any
*electrical* measurement made at a single frequency in the steady
state... and those were exactly the conditions that burned up your
transmitter, so the substitution principle is valid for this branch of
the discussion.

That whole principle relies on the fact that, at the same frequency and
in the steady state, the "definition of impedance" in terms of its
electrical properties does *not* change. That's the whole point.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek

Ian White, G3SEK wrote:
You are using that principle of impedance substitution whenever you
calibrate your antenna impedance bridge using known values of resistORS,
capacitORS and inductORS.

Yes, but I comprehend what I am doing. For you to imply the "electrical
properties don't change" between a 50 ohm dummy load and a 50 ohm dipole
antenna is simply ridiculous.

That whole principle relies on the fact that, at the same frequency and
in the steady state, the "definition of impedance" in terms of its
electrical properties does *not* change. That's the whole point.

The electrical properties *can* change and that's the whole point. The
electrical properties of a 50+j0 dummy load and a 50+j0 antenna are
almost completely different.

A transmission line can transfer photons. Can a lumped constant L-C
model transfer photons?
--
73, Cecil http://www.qsl.net/w5dxp



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W5DXP wrote:
Ian White, G3SEK wrote:
You are using that principle of impedance substitution whenever you
calibrate your antenna impedance bridge using known values of
resistORS, capacitORS and inductORS.

Yes, but I comprehend what I am doing. For you to imply the "electrical
properties don't change" between a 50 ohm dummy load and a 50 ohm dipole
antenna is simply ridiculous.

I didn't either say that or imply it. What's truly "ridiculous" is for
you to *infer* that I did.

I think I've already made my points well enough for other readers to
judge, so I really am done this time.

No doubt you'll have the last word, Cecil. Use it well.

--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek

Ian White, G3SEK wrote:

W5DXP wrote:
Yes, but I comprehend what I am doing. For you to imply the "electrical
properties don't change" between a 50 ohm dummy load and a 50 ohm dipole
antenna is simply ridiculous.

I didn't either say that or imply it. What's truly "ridiculous" is for
you to *infer* that I did.

I didn't have to infer anything, Ian, those words in quotes are *your
quoted words*. Here they are again:

That whole principle relies on the fact that, at the same frequency
and in the steady state, the "definition of impedance" in terms of
its electrical properties does *not* change.

That certainly implies that there is no difference between the electrical
properties of the impedance of a 50 ohm dummy load and a 50 ohm antenna.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil begs to differ:

The electrical properties *can* change and that's the whole point. The
electrical properties of a 50+j0 dummy load and a 50+j0 antenna are
almost completely different.


Like what, as far as the source and feedline are concerned?
Ain't that basically "AC" RF power being produced by the TX, flowing through
the transmission line, to 50+j0? (Resistance/impedance)
Who gives the hoot if that 50+j0 is power eating resistor or power barfing
antenna. Call it virtual(y) non-radiating antenna or virtual(y) radiating
resistor. Simply transducers looking pretty to the feedline and doing their
assigned thing. F the SWR, matchit !
RIP

BUm

Yuri Blanarovich wrote:
Who gives the hoot if that 50+j0 is power eating resistor or power barfing
antenna.

You don't care whether all your power is going into a dummy
load or into your antenna?

We are trying to figure out something about transmission lines
so we take away the transmission line and replace it with an
"equivalent circuit" that doesn't act like a transmission at all?
How in the world does that tell us anything about transmission
lines?
--
73, Cecil, W5DXP

Yuri Blanarovich wrote:
Who gives the hoot if that 50+j0 is power eating resistor or power barfing
antenna.
1
You don't care whether all your power is going into a dummy
load or into your antenna?
2
We are trying to figure out something about transmission lines
so we take away the transmission line and replace it with an
"equivalent circuit" that doesn't act like a transmission at all?
How in the world does that tell us anything about transmission
lines?
--
73, Cecil, W5DXP

1
Am I getting sucked into the bottomless black hole of transmission lines?
Yea, I care! If I want to test or tune my transmitter or amplifier and need a
dummy, I use dummy load. When I need to radiate killer signals I use my Razor
beams, but they are designed to have 50 ohm impedance and broad bandwidth
(possible, been there, done it) no matching crap, no reflections (ok very
small) and I don't give a Freak about nurturing reflections on the line. I hate
reflected waves and I suppress their generation/reflection/travel and endless
discussions about problem that nobody wants.

2
Huh? You haven't figured that SWR is bad for transmission lines?
All I want to know about transmission line that it doesn't have impedance
bumps, keeps its impedance, that it has lowest possible loss and doesn't
radiate or let the water in. (That goes for open wire feeders too :-)
Oh, color doesn't matter and it should be repulsive to chipmunks and other SWR
ignorant critters.
Why is this endless argument about reflections going on? We know they are bad,
we know how to eliminate them, so what's the problem? You love them so much
that you want to keep them in your coax?
There are no reflections around this shack, only in the mirror of my ugly face
after 48 hr contest.
OK hit me now that it is impossible to have reflectionless antenna-coax-tx.
My answer, yea, there are some (very little) and they are insignificant to me
to worry about and lose sleep and hours at the keyboard. Ins't it like eunuch
dreaming about sex? :-)

SK
73 Yuri da noSWR BUm

Yuri Blanarovich wrote:
Huh? You haven't figured that SWR is bad for transmission lines?

An SWR between 4:1 and 16:1 is what allows me to use a 130 ft.
$20 dipole fed with 400 ohm window line on all HF bands without
needing an antenna tuner. What's wrong with live and let live?
I find your approach to antennas boring as heck but I am not
going to rag on you about it. Different strokes for different
folks. One has to have a transmission line anyway - might as
well let it perform the matching function.
--
73, Cecil http://www.qsl.net/w5dxp



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