{Collins} Re: S meter 75S3



Most of the newer equipment have VERY liberal "S"
meters!  The older equipment used 50 microvolts
matched into a 50 ohm impedance (Collins used a 100
microvolt through a matching resistor which is the
equivalent of 50 microvolts into 50 ohms) for an S-9
reading.  I have found plenty of the newer equipment
that read as little as 10 microvolts for S-9 and then
for 40 dB over S-9 read under 50 microvolts!

Frankly, when S-9 = 50 microvolts, 20 dB over S-9 =
500 microvolts and 40 dB over S-9 = 5000 microvolts! 
That is "one heck of a signal"!

The reason that so many of the newer manufacturers
make their "S" meters read high with such low signals
is to give the impression that their receiver is more
sensitive than the next manufacturer.  Then the next
manufacturer does the same thing.  The result is that
on the newer equipment (at least most of it that I
have checked with a service monitor with a very
accurate attenuator) will almost read S-9 if someone
drops a crystal in the next county!

The result is that so many operators give 20 dB, 40
dB, and even 60 dB over S-9 reports (60 dB over S-9 is
50,000 microvolts under the old system) that everyone
is used to getting these reports.  Thus, when a
receiver that is calibrated for S-9 = 50 microvolts
and the "S" meter truly reads 20 dB over 9 for a 5000
microvolt signal is used often the signals are very
weak in terms of "S" meter reading.  But, the signal
is perfectly copiable!

When you give someone who is used to getting the 60 dB
over 9 reports an S-3 or S-4, he/she is "insulted" and
will usually come back giving you an even lower
reading!  Frankly, there are very few signals on the
bands that go as high as 20 dB over S-9 on any of my
receivers.  In fact, at times, their signal may not
even read on the "S" meter.  But, so long as the
signal is "out of the noise level", they are "perfect
copy".

I don't like to give out "S" meter readings these days
because of all the problems with the unreasonably high
readings of the newer equipment!  If the station has
given me at least an S-9, and if he is copiable, then
I usually say 5x9 just to keep the peace!  Otherwise,
I conviently avoid giving "S" meter readings!

Glen, K9STH


--- Kenkai@xxxxxxx wrote:

The S meter on my 75S3 seems sluggish.  Signals which
are 20 over 9 on my Icom transceiver meter barely
register on the Collins meter. I calibrated the meter
and adjusted the rf gain control so the the receiver
hears well.  Anyone have any ideas?  


=====
Glen, K9STH

Web sites

http://home.comcast.net/~k9sth
http://home.comcast.net/~zcomco


		
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