"Richard Harrison" wrote in message
...
In the telephone industry, the most common reference level is one
milliwatt.

Ditto the RF industry.

Signal loss is common.

Pretty ubiquitous... something about the three laws of thermodynamics... ;-)

Other dB units are easily contrived. There are dBw (dB referenced to one
watt), dBk (dB referenced to one kilowatt), dBRAP (dB above reference
acoustical power which is defined at 10 ro the minus 16 watts), etc,

The cable TV industry likes to use dBuV, for whatever odd reason.