[BC] Scope for Mod Monitor...

[Cowboy]

On Wednesday 19 July 2006 04:42 pm, Robert Meuser wrote:
> 
> Not really, Jerry. The FCC van I saw used a VFO and a frequency counter 
> to calibrate the demodulator. You could also take the IF of the wideband 
> demodulator and tap it off to a narrow band general coverage receiver 
> and use it to determine the Bessel null.

 Yes, we used to do it that way with absolute accuracy and precision, but
 ever since that whole ModMinder rules change thing, where a peak isn't
 a peak unless it exceeds some duration, and still isn't a peak unless
 there are so many of them in a minute, even though the scope will
 clearly show the absolute deviation which used to be the mod limit......

 So, does the first peak count when there are too many of them, or only the
 ones after the count limit ?
 We know that modulating 200% or 750% isn't over-mod anymore, as long
 as the peak is less than so much duration, and there are only so many
 per minute, so I'm not so sure a scope, with it's absolute accuracy and
 precision, is any good at all ! Especially if there are very few
 in rapid succession in any given minute. It's near impossible ( actually,
 not near at all for me ) to determine the duration of each peak, and count
 them simultaneously, while not missing other peaks and watching the
 clock at the same time.

 It seems today, that one can make a pretty good argument that there
 is no reliability to a scope for measuring FM modulation at all anymore.

 "Progress" is not always a good thing.
 It seems that the unintended consequence of that rule change ( or perhaps
 VERY intended by the guy making the argument in favor ) is that one
 MUST have a new mod monitor built to the new spec. so that it can ignore
 over mod that isn't mod at all.

 BUT I'M NOT BITTER !!
 :-)

-- 
Cowboy