Note:
Short wave (SW)
Radio broadcasting transmit has a strong time and frequency variations, the same radio broadcasting station have sometime broadcasting , sometime do not broadcasting, they may be used without frequency broadcasting in different time periods. Therefore, there must be a Frequency time table or according experience to receive, otherwise, it is difficult to find it
Single sideband (SSB)
It is the need to have a known frequency listening, attention, is observe listening, not listening, Observe listening like a walkie-talkie, as has been guarding at that frequency, only can hear when there are broadcast or have conversation
Air Band (AIR)
Location to be close to the airport in order to receive.
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