Errr, no, the meter is telling what it sees at the point of
measurement.

=====================================

But the meter is not seeing an SWR because an SWR does not exist.

Where is the 50-ohm transmission line on which the SWR is imagined or
supposed to lie?

As you are unable to answer that question, the remainder of your
argument (which, as I say, arises because of the SWR meter misleading
misnomer) falls flat on its face.

You are an intelligent person. I don't doubt you have no problems
with understanding what the so-called SWR meter really indicates. But
you didn't learn this from observations of the SWR meter - as you
already know it tells lies!

Just to reiterate, the so-called SWR meter indicates only whether or
not the load on the transmitter is a resistive 50 ohms. If it is not
50 ohms it will not tell you what it actually is. Not that you need to
know what it actually is because you will readjust your tuner, without
thinking about it, to make it equal to 50 ohms. Which corresponds to
no deflection of the meter needle.

The TLI is a very useful and valuable device. It does not lead
novices and old-wives (who ought to know better) into false ideas, or
cause confusion and misunderstandings within the amateur fraternity.
Professionals dismiss SWR for what it is worth anyway.

Goodby to SWR except on lines where it matters and where it can be
measured. Which, in practice, are very few.
---
Reg, G4FGQ.

Reg Edwards wrote:
Where is the 50-ohm transmission line on which the SWR is imagined or
supposed to lie?

On my system, there's a 50 ohm cable from the transceiver to
the input of the SWR meter and another 50 ohm cable from the
output of the SWR meter to the balun. Each of these cables
forces the ratio of the voltage to current in each of the
traveling waves to a value of 50 ohms. I have an in-line
Autek WM-1 and no tuner.
--
73, Cecil http://www.qsl.net/w5dxp

"Cecil Moore" wrote

On my system, there's a 50 ohm cable from the transceiver to
the input of the SWR meter and another 50 ohm cable from the
output of the SWR meter to the balun. Each of these cables
forces the ratio of the voltage to current in each of the
traveling waves to a value of 50 ohms. I have an in-line
Autek WM-1 and no tuner.
--
====================================

Cec,
You can't measure SWR on a line which is less than 1/4-wave long.
Preferably it should be as long as 1/2-wavelength to ensure the max
and min voltage points both occur on it.

But what do you do with the SWR when you have measured it? Of what use
it?

All anybody needs to know is whether the transmitter is terminated or
is not terminated with 50-ohms. This is very important.

And when describing to a novice how your station works there's no need
to mention SWR or reflections. They are quite unecessary complications
and can be dispensed with except perhaps for trolling on newsgroups.
----
Reg.

Reg Edwards wrote:
You can't measure SWR on a line which is less than 1/4-wave long.

Because your measurements are taken 1/4WL apart, your SWR value
will be in error for all feedlines except lossless ones.

SWR can be had at any point on a transmission line.
Measure the forward power and reflected power at any point.
SWR = [SQRT(Pfor)+SQRT(Pref)]/[SQRT(Pfor)-SQRT(Pref)]

The transmission line length must only be long enough such that
the V/I ratio is forced to the Z0 value. According to some pretty
smart guys I asked, that's about 2% of a wavelength.
--
73, Cecil http://www.qsl.net/w5dxp

Reg Edwards wrote:

"Cecil Moore" wrote

On my system, there's a 50 ohm cable from the transceiver to
the input of the SWR meter and another 50 ohm cable from the
output of the SWR meter to the balun. Each of these cables
forces the ratio of the voltage to current in each of the
traveling waves to a value of 50 ohms. I have an in-line
Autek WM-1 and no tuner.
--
====================================

Cec,
You can't measure SWR on a line which is less than 1/4-wave long.
Preferably it should be as long as 1/2-wavelength to ensure the max
and min voltage points both occur on it.

Total and absolute nonsense.

Where do you come up with this stuff?

snip arm waving speech

--
Jim Pennino

Remove .spam.sux to reply.

Reg Edwards wrote:
Errr, no, the meter is telling what it sees at the point of
measurement.

=====================================

But the meter is not seeing an SWR because an SWR does not exist.

Nonsense.

Where is the 50-ohm transmission line on which the SWR is imagined or
supposed to lie?

In my personal case, there is 50 Ohm transmission line between the
transceiver and the SWR meter, then a length of line to a coax switch,
then several lines out to antennas.

You seem fixated on haveing some magical length of transmission line
being necessary for a SWR to exist. This is nonsense.

As you are unable to answer that question, the remainder of your
argument (which, as I say, arises because of the SWR meter misleading
misnomer) falls flat on its face.

You are an intelligent person. I don't doubt you have no problems
with understanding what the so-called SWR meter really indicates. But
you didn't learn this from observations of the SWR meter - as you
already know it tells lies!

Babble.

A SWR meter indicates what is. Knowing what the reading really means
is a matter of education, not veracity.

Just to reiterate, the so-called SWR meter indicates only whether or
not the load on the transmitter is a resistive 50 ohms. If it is not
50 ohms it will not tell you what it actually is. Not that you need to
know what it actually is because you will readjust your tuner, without
thinking about it, to make it equal to 50 ohms. Which corresponds to
no deflection of the meter needle.

With some education and multiple measurements, you can caluclate
the actual impedance if one desires.

What tuner? What makes you believe everyone has a tuner?

The TLI is a very useful and valuable device. It does not lead
novices and old-wives (who ought to know better) into false ideas, or
cause confusion and misunderstandings within the amateur fraternity.
Professionals dismiss SWR for what it is worth anyway.

The only one I see confused is you and professionals use SWR all the
time and in many systems it is extremely important.

Goodby to SWR except on lines where it matters and where it can be
measured. Which, in practice, are very few.

If one knows what they are doing, SWR can always be measured.

---
Reg, G4FGQ.



--
Jim Pennino

Remove .spam.sux to reply.

Jim wrote,

If one knows what they are doing, SWR can always be measured.

===================================

NOT on a line which isn't there. QED.
---
Reg.

On Mon, 26 Sep 2005 16:20:14 +0000 (UTC), "Reg Edwards"
wrote:
Jim wrote,
If one knows what they are doing, SWR can always be measured.
NOT on a line which isn't there. QED.

Hi Reg,

Which only proves Jim is correct, in that you reject the facility to
do it with a line. My SWR meters do in fact have a 50 Ohm line
transiting from the gozinta to the comesouta. Your poor choice of
vendor, or poor solution implemented in design is your own problem,
not that of the world's.

I see that you still enjoy its mutilated discussion to the obvious
neglect of magnetrons. Much better than flogging Kelvinator, I
suppose.

Now there's an image, you going nose to nose with him. He'd send you
back to lower 6th for missing the bloody obvious.

73's
Richard Clark, KB7QHC

Reg Edwards wrote:
Jim wrote,


If one knows what they are doing, SWR can always be measured.


===================================

NOT on a line which isn't there. QED.
---
Reg.

Perhaps this is a dumb question Reg, but if the transmission line isn't
there, how does RF get from the transmitter to the antenna?

Thanks, ac6xg

Jim Kelley wrote:



Reg Edwards wrote:

Jim wrote,


If one knows what they are doing, SWR can always be measured.


===================================

NOT on a line which isn't there. QED.
---
Reg.


Perhaps this is a dumb question Reg, but if the transmission line isn't
there, how does RF get from the transmitter to the antenna?

Thanks, ac6xg



Well there's wave guide, there's printed circuit traces, there's wire.
OPPS.... those are transmission lines.

Dave WD9BDZ