In article ,
"Bob D." wrote:

What is the bandwidth of standard narrow band FM as we use it on 2 meters?
Is there a rule of thumb based on deviation? (I don't want to get into the
heavy math, I just know it's more complex than AM or SSB.)

Bob-

Although 5.0 KHz peak deviation has been a defacto Ham standard for
around 30 years, equipment manufacturers frequently also have a
commercial product line. They will often adjust equipment the same for
both lines. Recent Ham equipment is being shipped with peak deviation
ranging from about 3.5 KHz to 5.0 KHz. That represents a 3 dB range of
adjustment, which is just noticeable to the ear.

A more appropriate question might be what should the average deviation
be? Many people like to hold the microphone several inches away from
their mouth. They may not like the sound of wind-blast resulting from
holding the microphone next to their mouth. Unfortunately the radio may
be set up for close talking, and might easily have 10 dB lower audio as
a result of holding the microphone away from the mouth.

Ham Radio is not Broadcast Radio. To keep background noises low and
voice level high, I would vote for close-talking and an average level of
around 3 KHz deviation.

Fred
K4DII