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Old November 27th 04, 03:50 PM
James Bond
 
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The 756 pro is "properly" calibrated, each S-Point is individually
calibrated.

Sam
"xpyttl" wrote in message
...
"Reg Edwards" wrote in message
...

Most people appear to be fatally attempting to use, in reverse, their
favourite S-meter as a means of calibrating the Standard. No wonder we

have
so many different standards around.


We have seen a dozen or so posters indicate that S9=50uv

Nowadays, very few rigs have analog meters. Instead, they have a computer
that can take that AGC voltage and display it however the computer
decides.

In the Icom calibration procedure for the 706, there are three calibration
points known by the computer ... S0 (0 uv), S9 (50 uv), and S9+60 (50 mv).
The calibration procedure sets these three with known inputs, and
presumably
the computer interpolates from there. That really isn't a bad
calibration,
and I'd be surprised if other modern rigs were much different.

Now it is quite likely that there is some dependence on the AGC voltage
with
frequency, but again, in a modern rig that should be manageable.

What isn't so constant, of course, is the antenna. The voltage at the
receiver could range over several orders of magnitude for the same signal
depending on the antenna. So in terms of providing input to the sender,
the
S meter reading is still of limited usefulness, even if we all had
calibrated radios and agreed that S9=50uv.

..




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