[Premium-Rx] On the Relativity Theory Of Signal Strength Meters

[John Fallows]

S-Meters, of course, are not really signal strength meters in most
receivers, they are AGC voltage meters, whose characteristics are determined
by the agc loop and particularly bandwidth filtering.  Given the dynamic
range of modern recievers, signal strength must be presented on a non-linear
scale, i.e. dBm not mw.  S-Meters do a pretty good proxy, although
calibration (which is oftem imaginary at best) is also thrown off by
reduction of RF gain.

Manufacturers have not really taken advantage of their DSP advances to
re-think signal information presentation.  It is kind of wasteful that
modern DSP receivers generally just present S-Meter and perhaps dBm data.
The big emphasis seems to be either retaining an analog meter, or achieving
its look and feel on the LCD display.

More to the point, DSP can provide a great deal of analytical information
such as signal-to-noise ratio.  I suspect that the software defined radio
community may be the ones identifying some new metrics and information
displays that will support users in optimizing receiving chain
characteristics to various signals.

This might be a topic worthy of consideration:  if we forget about our
"traditional receiver controls", what displays and controls might we want to
create to take advantage of digital rather than analog signal proccessing?

73 John Fallows VE6MBA