Icom M802 User Manual page 10

Here is a simple formula to figure an approximate range of reception.
MHz x 100 = expected minimum range
MHz x 200 = expected maximum range
Marine SSB channels, and their approximate range, are listed here:
2 MHz 0-200 miles
4 MHz 400-800 miles
6 MHz 600-1200 miles
8 MHz 800-1600 miles
12 MHz 1200-2400+ miles
16 MHz 1600-3200+ miles
22 MHz 2200+ miles
26 MHz 2600 + miles
Most marine SSB transceivers are loaded with all worldwide ITU
channels, identified with 3 or 4 digit designators beginning at 401, and
ending at 2510. RARELY will you hear anything but static. But within
each ITU BAND are specific marine SSB channels. While some are
simple "talk or listen" (SIMPLEX) channels sharing a single frequency,
most are simultaneous "talk and listen" (DUPLEX) channels made up of
closely spaced but separate transmit and receive frequencies.
Most DUPLEX ITU channels, such as ITU no. 411 and ITU no. 2203, are
associated with major shore stations and telephone interconnect
facilities. Domestic and international GMDSS rescue agencies,
including the US Coast Guard, use a duplex channel in each band for
weather broadcasting and routine communications. While competition
with global sat phone networks has pushed most of the telephone
interconnect stations off the air, we still have one powerful USA Public
correspondence station, WLO, in Mobile, Alabama with companion
very short range, local
popular race and regatta channels
excellent skywave, short range
medium range, day and night
long range "high seas", days and
evenings
long range "high seas", days
very long range, days
few skywaves until 2009
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