[PVRCNC] S Meter Calibration

[Brian Alsop]

Guys,

Interesting reading:

The contest rate sheet has a link to extensive studies showing how bad 
present generation equipment
S meters really are for a wide variety of xcvrs. Generally accepted 
standards are 50 microvolts for S9 and 6db/S-unit.

The correct link is:
http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/SMeterBlues.htm#

They show most Rx's have only a few db/s-unit.  They also show a total 
range from S0 to S9 of about 25 db instead of 54 db. 

This seems to explain why one can hear so many signals below S0 so 
clearly. 

Calculations using the link's figures shows that most current generation 
rigs have SO of about 3 microvolts--assuming S9 is 50 microvolts.  Most 
RX's can detect 0.15 microvolt signals in a quiet environment.  Thus 
there are really 4 S-unit available for detection below S0! 

The old HQ-129X receiver really did have 6 db/s-unit and 50 microvolts 
for S9.  S0 was truly at or near the RX's limits of detection.

Maybe the current generation rigs need an S-meter with negative S-unit 
values.   That ought to help sales.  "My receiver is hearing signals 4 
S-units below S0 what is yours saying?"

Marketing corrupts......

73 de Brian/K3KO