At risk of being called a Troll, and having little else to do at
present, I copy from another newsgroup the following text.

"Reg Edwards" wrote -

"The effect of an impedance mis-match at a coaxial connector of
ordinary dimensions is practically zero at frequencies up to UHF.

Regardless of its other dimensions, the primary requirement of a
mismatched connector is that its length should be appreciably less
than 1/4-wavelength at the highest working frequency.

People are unnecessarily worried at VHF and below. Mix up 50 and
75-ohm connectors, and indeed connectors of unknown Zo, and carry on
regardless.

For an analysis of performance, download in a few seconds and run
immediately program CONNECT from website below."

Program CONNECT will calculate the effect on performance of inserting
any relatively short length of line, of Zo different from system Zo,
into the system. It's less than the inexperienced might imagine from
reading frightening magazine and handbook articles about impedance and
conjugate mis-matches.

If you have a short length of coax lying around, of unknown Zo, just
use it!
----
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. ..........

Reg Edwards wrote:
Regardless of its other dimensions, the primary requirement of a
mismatched connector is that its length should be appreciably less
than 1/4-wavelength at the highest working frequency.

Yes, at HF the reflections from one impedance discontinuity
and the reflections from a complimentary impedance discontinuity
3 inches away almost entirely cancel each other.
--
73, Cecil http://www.qsl.net/w5dxp

Reg Edwards wrote:
Regardless of its other dimensions, the primary requirement of a
mismatched connector is that its length should be appreciably less
than 1/4-wavelength at the highest working frequency.
======================================

Yes, at HF the reflections from one impedance discontinuity
and the reflections from a complimentary impedance discontinuity
3 inches away almost entirely cancel each other.
--
73, Cecil
========================================

Reflections are functions of TIME, not frequency.

Oliver Heaviside had the right idea long before the invention of the
SWR meter.
-----
Reg, G4FGQ.

"Reg Edwards" wrote

Reflections are functions of TIME, not frequency.

Oliver Heaviside had the right idea long before the invention of the
SWR meter.
====================================

For "reflections" also read "Echos".
-----
Reg, G4FGQ.
====================================

On Wed, 23 Aug 2006 00:54:51 +0100, "Reg Edwards"
wrote:


"Reg Edwards" wrote

Reflections are functions of TIME, not frequency.

Oliver Heaviside had the right idea long before the invention of the
SWR meter.
====================================

For "reflections" also read "Echos".

Hi Reggie,

You are in fact wrong in all accounts. Reflections are functions of
distance - as are echoes. This is a phase issue. Time and frequency
are always inseparable as Kelvin would instruct you in first
principles before another hunk of chalk was winged off your noggin.

You may choose to render phase into time, but shift the frequency and
the phase shifts, not the distance. Mismatched Zo connectors do not
shrink or enlarge with frequency - the effects may, but physical
components rarely follow such perturbations.... until an arc-over
that is the classic failure mechanism for such mismatches (obviously,
and deliberately ignored in this thread).

73's
Richard Clark, KB7QHC

Ric,
Yet again, like a Catherine Wheel, you are flying off in convoluted
tangents.
-----
Punchinello

"Reg Edwards" wrote

Reflections are functions of TIME, not frequency.

Oliver Heaviside had the right idea long before the invention of
the SWR meter.
====================================

For "reflections" also read "Echos".
====================================

The reason there are so many misunderstandings about SWR is that SWR
meters are based on impedance and frequency. Not a simple concept.

Whereas reflections (echos) (which according to Cecil are what it's
all about) are functions of time and distance. With which we are very
familiar.

Unfortunately, there does not appear to be a simple measuring
instrument which could replace the SWR meter. Any ideas?

But we would still need an instrument, a TLI, which indicates whether
or not the transmitter is correctly loaded with 50 ohms. So perhaps
things are best kept as they are.

Just rename the SWR meter!
-----
Reg, G4FGQ.
====================================

Reg Edwards wrote:
Reflections are functions of TIME, not frequency.

Remember that in the (2*pi*frequency*time) term used
to describe reflections, frequency is just as important
as time.
--
73, Cecil http://www.qsl.net/w5dxp

In article , "Reg Edwards"
g4fgq,regp@ZZZbtinternet,com wrote:

Reflections are functions of TIME, not frequency.

Oliver Heaviside had the right idea long before the invention of the
SWR meter.
-----
Reg, G4FGQ.

Hello, and the present or absence of reflections in the steady-state (no
transients as one would see when the system is first energized) is by
comparison of an impedance (Zx) at a measurement point to some reference
impedance (Zo). This reference impedance can be associated with the
characteristic impedance of a transmission line or some other system
characteristic. If Zx and/or Zo varies with frequency (has a reactive
component) then the RMS amplitude of the voltage/current reflections also
varies with frequency. We use this property to match Zx to Zo at some
frequency by minimizing the measured reflected voltage (or current or
power).

In the steady-state there is one voltage/current (as seen by an RF
voltmeter or ammeter) placed at the measurement point. We need a
directional coupler (part of a Bird model 43) or impedance bridge
(referenced to Zo) inserted at the measurment point in order to partition
the sampled voltage/current into incident (forward) and reflected waves.
I'm not sure exactly what Reg meant. Sincerely, and 73s from N4GGO,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

J. B. Wood wrote:
In the steady-state there is one voltage/current (as seen by an RF
voltmeter or ammeter) placed at the measurement point. We need a
directional coupler (part of a Bird model 43) or impedance bridge
(referenced to Zo) inserted at the measurment point in order to partition
the sampled voltage/current into incident (forward) and reflected waves.

Hi John, one important fact that some people would like to
forget is that the reflected wave can indeed be partitioned
from the forward wave. Some people on this newsgroup argue
that the forward wave and reflected wave are inseparable and
that reflected waves contain no rearward traveling energy.

However a circulator plus load resistor located at the source
will prevent reflected wave energy from being incident upon
the source and will heat up that load resistor in the process
proving that reflected waves are real and do contain energy.

My favorite illustration of such is a one-second lossless
transmission line with reflections. The number of watts in
the forward wave plus the number of watts in the reflected
wave equals the number of joules stored in the line during
steady-state. For instance, if Pfor = 200w and Pref = 100w,
then 300 joules of RF energy exist in the one-second long
lossless line during steady-state.
--
73, Cecil, http://www.qsl.net/w5dxp