[CQ-Contest] RE: Aren't M/Ms Annoying?

[Bill Tippett]

NT5C wrote:
 >All weekend in CQWW, a certain well-known M/M was camped on 21200.5, and 
was of course audible down to 21199 or so. Does anyone care anymore? Sure 
they were on USB, but isn't it true that no part of our signal is supposed 
to percolate outside the legal band? I'm sure there must be a technical 
justification that I'm missing.

         There is.  When you set your receiver passband to 21199 in USB,
it is typically receiving from 21199 to 21202 (3 kHz bandwidth), so
naturally you "hear" the portion of the station's signal that falls within your
passband (i.e. 21200.5 to 21202).  This does NOT mean their signal is out
of the band.  To check for emissions below 21200, set your passband to
LSB and your receiver to 21200.0.  Any emissions should be at least
40 dB down to meet FCC regulation 97.307.  Yours is a very common
misconception and even some ARRL Offical Observers do not understand
this so don't feel bad.

                                         73,  Bill  W4ZV