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
very short range, local
4 MHz
400-800 miles
popular race and regatta channels
6 MHz
600-1200 miles
excellent skywave, short range
8 MHz
800-1600 miles
medium range, day and night
12 MHz
1200-2400+ miles long range “high seas”, days and
evenings
16 MHz
1600-3200+ miles long range “high seas”, days
22 MHz
2200+ miles
very long range, days
26 MHz
2600 + miles
few skywaves until 2009
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
