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Introduction
SHORT WAVE (SW)
Your world receiver can receive a number of wavebands. Most of these
are known and tuning to the required station will soon become a matter
of routine, as the stations are always to be found at the same place on
the dial and are thus tied to a fixed wavelength and frequency.
- With short wave this is unfortunately not always the case. Short-wave
transmitters have to change their wavelengths fairly often. In the short-
wave range between 10 and 100-metre wavelength (frequencies of 30-
3 MHz resp.) nine bands between 10 and 50 metres are allocated to
short-wave broadcasting, with another four bands between 60 and 120
metres for broadcasting in the earth's tropical areas. The latter are
roughly located between the latitudes of 30º north and 30º south, i.e.
"around the equator. Most short-wave broadcasting bands, indicated in
the frequency range table, are allocated for the whole world and can be
used for international broadcasting. They are so far the only
wavelengths which allow direct radio reception over long distances. So
in addition to the broadcasting services, there is a large number of
other users of short wave, for example radio amateurs, shipping and
aviation, radio navigation etc.
TROPICAL BAND (TB)
Some versions are equipped with a tropical band TB. The TB (tropical
band, 60 - 120 metres) is a part of the short-wave band and is used for
broadcasts in tropical areas.
TIME ZONES
The earth rotates around its axis in 24 hours and around the sun in one
year.
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These movements are responsible for the time differences and the
seasons on earth. Due to the direction of rotation of the earth it is
always earlier in the day to the west of where you are and later in the
day to the east of where you are.
The earth is divided into 24 time zones with a difference of one hour
between adjacent zones. The system is based on one standard time
zone, namely UTC (Coordinated Universal Time), previously GMT
(Greenwich Mean Time). Generally speaking, short-wave stations
announce their broadcasts in UTC.
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