I couldn't resist the temptation to copy the following messages from the UK
newsgroup.

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The so-called swr meter is no more and no less than a simple RF
resistance
bridge which is either balanced or unbalanced. Usually the latter.


Reg,
I know you 'have a thing' about the SWR meter not measuring SWR.
I have an ohm-meter. It doesn't 'measure' ohms. It actually measures
current.
How many 'meters' actually measure what we say they measure?
Speedometer?
Flow-meter?
Odometer?
Kill-ommeter? (as pronounced by thickies - ugh!)
Methinks thou splitteth hairs.
Ian.

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The current which is 'measured' by an ohmeter actually exists.

Yet another reason why the so-called swr meter does not measure swr is
because there is no transmission line (between meter and transmitter) on
which to measure it. SWR on it cannot not exist.

Ian, without wishing to cause the slightest offence, I'm afraid your long,
ingrained, aquaintance with the old-wives' tales surrounding swr meters is
preventing you (and others) from seeing things from a different point of
view.

The instrument is just a 4-arm RF resistance bridge, the arm subject to
variation being the input impedance of the transmission line to the antenna
which can be any Zo you like. The other 3 arms are fixed.

The 'meter' merely indicates whether or not the input impedance of the
line-to-the-antenna is some special value of ohms (usually 50) because that
is the desired transmitter load.

It won't, and cannot even, tell you what the value of that special value
actually is except under the very exceptional condition that it is exactly
correct.

And it tells you absolutely nothing else about what exists or is going on in
the station unless you deduce and add to it what you already know by other
means anyway.

My objection to current practice arises because the invalid name of the
instrument, plus all the arguments which arise in futile attempts to justify
it, cause nothing but emotional confusion amongst novices and old-wives
alike.

So why not just change the name to TLI (Transmitter Loading Indicator) and
all the confusion and arguments will cease. Novices will no longer have to
be re-educated about the true meaning and relevance of swr.

Or YOU can choose a new name if you wish and take the credit for it.

No circuit changes are needed. ;o)
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Regards, Reg, G4FGQ