Michael A. Terrell wrote:

Ken Scharf wrote:

BTW dB means deci-bell, why not use a WHOLE BELL.
(and the brass figligee with bronze oak-leaf palm to anybody
who can guess who this unit of measure was named after!)



Well, it wasn't named after Watson, so that only leaves one man...




Art Bell?

-ex

"Steve Nosko" wrote in message
...
Actually I believe the unit is a Bel. Yes 10 dB is one Bel. For some
reason nobody uses the bel...or for that matter the milibel, microbel,

This may interest some.
I believe, although can't find the actual reference now, that the decibel
was used rather than the bel from the start because the numbers were very
close to those of the m.s.c. used before it.
The following are from "Signal Training" Vol 2, Part 3 (Line telephony and
Telegraphy) 1936, HMSO, an Army training manual:-

" The decibel.- The standard unit for measurement of telephone transmission
in this country [UK] is now the decibel, which is one-tenth of a bel, and
has superseded the mile of standard cable."

and

"1 decibel = 1.084 m.s.c. = 1.151 decineper"
"1 m.s.c. = 0.9221 decibel = 1.0616 necineper"

and just to explain the decineper

"In the majority of European countries the unit of measurement for telephone
transmission is the decineper, which is one-tenth of one Neper. The unit is
named after Napier, the originator of Naperian or natural logarithms, i.e.
logarithms to the base e. The neper is a measurement of the total
attenuation and can be defined as the natural logarithm of the ratio of the
currents at two different points in a network or apparatus, or as half the
natural logarithm of the ratio of powers at two different points in a
network or apparatus."


The book doesn't show an upper case B for Bel in db so that must have come
later but it does use the plural as in "30dbs" so should we be using dbuVs
etc? I've used an artificial cable box for 75 ohm video but have never seen
a reference m.s.c., originally an actual lump of cable but later a series of
switched networks.

John
MW1FGQ