"Bill" wrote
I think it all boils down to signal to noise.
If you are trying to communicate with another station and he is putting
out
100 watts and is not being copied and then he puts out 110 watts and you
can
copy him that is what counts.

===============================

Bill, sorry to be so pessimistic.

If, because of bad signal to noise ratio you can't copy him when he's using
100 watts, then, as sure as eggs don't bounce off concrete, there's no hope
of any detectable improvement by increasing power to 110 watts or 0.4 dB.

Suppose when he's using 100 watts you can hear only 25% of words (or morse
characters). So you can't copy him.

If he doubles power to 200 watts you will still read only 40% of what he
says. So you still can't copy.

If he doubles power again to 400 watts you will be able to copy 60% of what
he says. You will still be in big trouble.

At 800 watts 80% of words (or characters) will be OK but it's not solid
copy. Requests to repeat will be common.

At 1600 watts 99% of words (or characters) will be OK and that's solid
enough.

There are many assumptions in the foregoing crude analysis. But as many have
experienced it is typical.

Claude E. Shannon's (of Bell Labs) original classical paper on the subject
of "Communication in the Presence of Noise", Jan. 1949 can be downloaded (I
have just discovered) by doing a Google on the title. Radio and phone
engineers had been trying for 40 years to describe in precise mathematical
terms the effects of noise and cross-talk in a communication channels. The
transistor had just been invented. So had PCM pre-war. But progress in the
design of the vast communication digital networks then envisaged and which
we now see was being impeded by the lack of understanding of the effects of
ever-present random noise.

It was basically a problem in Statistics. But Shannon went off at a tangent
back to Geometry where Pythagorus the ancient Greek had begun. He translated
the statistical problem into one of calculating the number of small spheres
which can be packed inside a much larger multi-dimensional sphere. The
calculating procedure acquired the everlasting name of "Ball Packing". It is
not difficult to understand. It was Shannon's dazzling multi-coloured flash
of inspiration which did the trick. His name has gone down in history. Think
of him the next time your electric light dimmer-switch goes faulty.
Following Shannon progress forged ahead. In-words such as signal-to-noise
ratios and error-rates became very popular.

A one-dimension sphere is a dot. A 2-dimension sphere is a flat circular
disk. A 3-dimension sphere is a ball. Followed by N-dimensions, all of which
have a surface area and and a volume involving Pi.
----
Reg.