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

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

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

The 50-ohm line on which the SWR is supposed to be measured is between
the transmitter and the so-called SWR meter.

If the transmitter is connected directly to the meter, (as it usually
is, very often it is inside the transmitter on the front panel) there
is no line and no SWR on it which can be measured.

Neverthess, the meter still provides a reading of SWR. Obviously it
is telling lies and causes confusion and misunderstanding to novices
about what is really happening within their equipment. In fact, just
as it has been doing since Joker, Richard Clark, entered the thread.

Some people force themselves to imagine a 1/4-wavelength transmission
inside the little box in a vain endeavor to explain how an SWR meter
works.

Actually the meter indicates whether or not the transmitter is loaded
with 50-ohms - and nothing else. It is an HF resistance bridge to
which its circuit reduces.

But, as I say, it is a very useful, almost indispensible instrument.
It is a TLI.
----
Reg.

On Mon, 26 Sep 2005 19:49:00 +0000 (UTC), "Reg Edwards"
wrote:

In fact, just
as it has been doing since Joker, Richard Clark, entered the thread.


Aw Reggie,

You are getting emotional because you were caught spitting on
Kelvinator and telling us it was the London fog.

73's
Richard Clark, KB7QHC

Reg Edwards wrote:

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


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

The 50-ohm line on which the SWR is supposed to be measured is between
the transmitter and the so-called SWR meter.

If the transmitter is connected directly to the meter, (as it usually
is, very often it is inside the transmitter on the front panel) there
is no line and no SWR on it which can be measured.

What you're saying is that there's a line connecting the transmitter to
the meter, but there isn't a line connecting the transmitter to the
meter. I'd have difficulty defending such a position.

Neverthess, the meter still provides a reading of SWR. Obviously it
is telling lies and causes confusion and misunderstanding to novices
about what is really happening within their equipment. In fact, just
as it has been doing since Joker, Richard Clark, entered the thread.

Some people force themselves to imagine a 1/4-wavelength transmission
inside the little box in a vain endeavor to explain how an SWR meter
works.

Actually the meter indicates whether or not the transmitter is loaded
with 50-ohms - and nothing else.

I don't think the meter really knows what impedance the transmitter is
loaded with. As far as I can tell, it only knows how many volts and
amps gozinta one port and/or compared with how many volts and amps
gozinta the other port.

But I agree that some people read an awful lot into the measurements
they make with one of these devices.

It is an HF resistance bridge to
which its circuit reduces.

True enough.

But, as I say, it is a very useful, almost indispensible instrument.
It is a TLI.

I like to think of it more as a reflectometer.

73 de ac6xg

Reg Edwards wrote:


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

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

The 50-ohm line on which the SWR is supposed to be measured is between
the transmitter and the so-called SWR meter.

No, the SWR being measured is on the load side of the meter.

If the transmitter is connected directly to the meter, (as it usually
is, very often it is inside the transmitter on the front panel) there
is no line and no SWR on it which can be measured.

Bzzzt, wrong answer. SWR is measured on the output side of the meter,
not the input.

Neverthess, the meter still provides a reading of SWR. Obviously it
is telling lies and causes confusion and misunderstanding to novices
about what is really happening within their equipment. In fact, just
as it has been doing since Joker, Richard Clark, entered the thread.

Some people force themselves to imagine a 1/4-wavelength transmission
inside the little box in a vain endeavor to explain how an SWR meter
works.

That would be inane.

All one need do is realize the meter measures toward the load.

Actually the meter indicates whether or not the transmitter is loaded
with 50-ohms - and nothing else. It is an HF resistance bridge to
which its circuit reduces.

But, as I say, it is a very useful, almost indispensible instrument.
It is a TLI.
----
Reg.



--
Jim Pennino

Remove .spam.sux to reply.

Jim says,
No, the SWR being measured is on the load side of the meter.
=========================================
Jim,

I have difficulty in telling you this without hurting your feelings.
Or perhaps you are just joking and pulling my leg. Try the other one -
its got bells on.

I will assume you are not joking. You clearly havn't the foggiest idea
of how the so-called SWR meter works. Although you may be in good
company - including not a few professional engineers who have picked
up old-wives' tales from radio amateurs. And have been led astray by
the meter being called something which it isn't.

The meter indicates SWR when placed at the ANTENNA end of the line. It
is the antenna which does the terminating. And the meter gives the
correct answers only when the line Zo = 50 ohms.

If there is a tuner or matching network in the line then the meter
will indicate SWR on the line between the transmitter and the tuner -
provided the meter is placed next to the tuner.

When there is no appreciable length of line between transmitter and
tuner (as is the very common case) there is no line on which to
measure SWR. But the meter will indicate an SWR - and tells lies.

But there's nothing to worry about just because the meter is
indicating SWR nonsense. The meter is telling you what you really
want to know, its exactly why you placed it there - whether or not
the transmitter is loaded with 50 ohms.
----
Reg.

Reg Edwards wrote:
Jim says,
No, the SWR being measured is on the load side of the meter.
=========================================
Jim,

I have difficulty in telling you this without hurting your feelings.
Or perhaps you are just joking and pulling my leg. Try the other one -
its got bells on.

Meaningless babble.

I will assume you are not joking. You clearly havn't the foggiest idea
of how the so-called SWR meter works. Although you may be in good
company - including not a few professional engineers who have picked
up old-wives' tales from radio amateurs. And have been led astray by
the meter being called something which it isn't.

I assure you I have a very good understanding of how SWR meters in
their various incantations work and how SWR works.

The meter indicates SWR when placed at the ANTENNA end of the line. It
is the antenna which does the terminating. And the meter gives the
correct answers only when the line Zo = 50 ohms.

A SWR meter indicates the SWR of whatever is connected to the load
side of the meter relative to the reference impedance the meter is
designed for.

It matters not if the thing connected to the load side of the meter
is an antenna, an antenna with a transmission line, a transmission
line with a dummy load on the end, or two popsicle sticks and a
bubble gum wrapper.

If you are only interested in the SWR of the antenna and don't, or
can't, correct for the effects of real transmission line in between
the meter and the antenna, then you have to connect the antenna
to the load end of the meter directly.

If there is a tuner or matching network in the line then the meter
will indicate SWR on the line between the transmitter and the tuner -
provided the meter is placed next to the tuner.

Tuners have nothing to do with the issue.

You can put a 1956 Buick on the load side of the meter; you still
read SWR of the system at the point of measurement.

It is you that is trying to confuse the issue with arm waving.

When there is no appreciable length of line between transmitter and
tuner (as is the very common case) there is no line on which to
measure SWR. But the meter will indicate an SWR - and tells lies.

Babbling nonsense.

But there's nothing to worry about just because the meter is
indicating SWR nonsense. The meter is telling you what you really
want to know, its exactly why you placed it there - whether or not
the transmitter is loaded with 50 ohms.

That is not what I would want to know.

I know the output impedance of the transmitter and the line (assuming
it is good) impedance.

What I want to know is the antenna SWR and the measurement of that is
trivial though it seems to have you totally confused.

----
Reg.


--
Jim Pennino

Remove .spam.sux to reply.