> The wrong things shouldn't be exaggerated then. We should
> focus on what
> really happens.
That's what I'm doing.
> The S meter doesn't measure "peak power". A more correct
> statement would be
> it measures the "average power of the peaks" (as in peak
> envelope power).
> But it is immaterial as it is the same meter that is being
> used to measure
> the fundamentals as is used to measure IM levels here.
Not any meter I've seen. They almost always work from the
AGC.
The AGC is generally a peak detection system with rapid
attack and slow decay, with the exception that a good weak
signal AGC will ignore very brief peaks.
An AGC that used averages would be terible on CW and SSB, as
would one that hung on very short duration peaks. There is
often group delay in the AGC attack caused by time delay in
filters so there might be some overshoot if the AGC controls
stages before the narrow filters.
I do agree the type of detection shouldn't be a major issue
in most receivers if you reset the meter level to the same
value and kept it low on the scale.
> "misses some of the third order and much of the higher
> order products" is a
> misleading statement too. In reality there is a sampling
> of all of those
> products with voice being used as it is a wide spectrum of
> tones generated.
> The resultant IM products will be represented in a rather
> narrow band.
I don't follow that.
> "probably isn't useful on the air except under certain
> conditions". No test
> of any kind is useful under all conditions. There are
> always limitations.
That's what we need to learn.
>> Who's going measure the dynamic range of various radios
>> using S meter movement?
>
> If someone measured their transmitter with their poor
> performing receiver
> and thought they had poor IM performance on their
> transmitter maybe that
> would be a good thing. That may prompt some further action
> into
> investigating why.
It could be a false good or a false bad reading.
> Seems better than to just throw up our hands and say "it's
> too complicated
> to try we're going to get the wrong answer".
I'm only saying it is necessary to know how the system
behaves before saying it is OK or not OK. We have to know
what it does and what it cannot do and explain it in a way
everyone understands, including limitations. Why would that
be a problem?
73 Tom
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