"William E. Sabin" wrote Reg Edwards wrote:

A so-called directional wattmeter or SWR meter merely responds to the
magnitude of a reflection coefficient usually, but not necessarily,
relative
to 50 + j0 ohms. Half of the information, the angle, is discarded
without
being aware of its existence.


Not exactly correct.

The phase information is not displayed explicitly
on a scaler instrument like the Bird meter, but
phase is definitely involved in the principles of
operation of the directional coupler.

Very seldom, if ever, do we care a feather or a
fig what the exact phase value is, but the
directional coupler is not balanced unless the
phase is zero.

All automatic antenna tuners utilize this fact.

Bill W0IYH

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

Bill, why the unnecessarily complications?

It is possible to imagine the so-called SWR meter is telling you the
imaginary value of the SWR on a non-existent transmission line. But it's
hardly of educational value when novices, even experienced engineers, are
trying to understand what the reading really means. It's as confusing and
as untruthful as Blair.

Why don't we accept the simple fact that the meter tells us only whether the
transmitter is loaded with a resistance of a particular value or not. Which
is no more nor less than what the instrument on the front panel of your
transceiver is provided for.

Then we can forget all about SWR, fwd and reflected power, until needed on
real ines. Change the name of the meter to TLI.
---
Reg, G4FGQ

"Reg Edwards" wrote in message
...
It is possible to imagine the so-called SWR meter is telling you the
imaginary value of the SWR on a non-existent transmission line. But it's
hardly of educational value when novices, even experienced engineers, are
trying to understand what the reading really means. It's as confusing and
as untruthful as Blair.

Why don't we accept the simple fact that the meter tells us only whether
the
transmitter is loaded with a resistance of a particular value or not.
Which
is no more nor less than what the instrument on the front panel of your
transceiver is provided for.

Then we can forget all about SWR, fwd and reflected power, until needed on
real ines. Change the name of the meter to TLI.
---
Reg, G4FGQ

Amen to that. I turned down the power on my transmitter, and measured P
forward and P rev while feeding about 100 feet of unterminated 9913. I then
REMOVED the coax; i.e. there was nothing connected to the output side of the
meter. Still measured the same Pf and Pr. (Daiwa meter)

Tam/WB2TT

Tarmo Tammaru wrote:
Amen to that. I turned down the power on my transmitter, and measured P
forward and P rev while feeding about 100 feet of unterminated 9913. I then
REMOVED the coax; i.e. there was nothing connected to the output side of the
meter. Still measured the same Pf and Pr. (Daiwa meter)

Of course, you were simply getting a same-cycle reflection. The reflected
wave model is consistent. If the open-circuit is at the transmitter terminal,
all the power is reflected immediately.
--
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! =-----

Cecil,

I don't have a schematic for the Daiwa. So, I don't really know what it was
measuring; but, I think more than likely, the voltage that reached the
meter. If the scale were calibrated in gallons per minute, I might have read
2.5 gallons per minute.

Tam/WB2TT
"Cecil Moore" wrote in message
...
Tarmo Tammaru wrote:
Amen to that. I turned down the power on my transmitter, and measured P
forward and P rev while feeding about 100 feet of unterminated 9913. I
then
REMOVED the coax; i.e. there was nothing connected to the output side of
the
meter. Still measured the same Pf and Pr. (Daiwa meter)

Of course, you were simply getting a same-cycle reflection. The reflected
wave model is consistent. If the open-circuit is at the transmitter
terminal,
all the power is reflected immediately.
--
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! =-----