[CQ-Contest] CM500 noise exclusion

[Art Boyars]

Somewhere in the ongoing thread K9YC addressed the the issue of the
MICROPHONE's excluding outside noise.

My original concern (not clearly expressed) was with the headphones'
keeping out the sounds from the furnace.

YC's point is valid.  However, with neither of the two boom headsets that I
have used has a QSO station ever complained that they can't hear me over
the furnace noise. They just complain that they can't hear me.  In SS SSB I
managed only ELEVEN Califorina QSOs.

73, Art K3KU