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Transmission power ranges between 1 and 25 watts, giving a maximum range of up to about 60 nautical miles (111 km) between aerials mounted on tall ships and hills, and 5 nautical miles (9 km; 6 mi) between aerials mounted on small boats at sea level. [7]
Very high frequency (VHF) is the ITU designation [1] for the range of radio frequency electromagnetic waves (radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency ...
VOR stations are short range navigation aids limited to the radio-line-of-sight (RLOS) between transmitter and receiver in an aircraft. Depending on the site elevation of the VOR and altitude of the aircraft Designated Operational Coverages (DOC) of at max. about 200 nautical miles (370 kilometres) [5] Att.C, Fig.C-13 can be achieved.
The U.S. National Distress System was established in the early 1970s [1] as a VHF-FM-based radio communication system that has a range of up to 20 nautical miles (40 km) along most of the U.S. shoreline for the United States Coast Guard.
A similar broadcast on MF is initially announced on 2182 kHz, with a further frequency specified, e.g., 1770 kHz. VHF optimum range is approximately 30 nautical miles (nmi), effectively line of sight, whereas MF range is much greater at approximately 150 nmi, allowing ships in the Atlantic Ocean and North Sea to receive the broadcast.
The National Distress and Response System (NDRS) was established more than 30 years ago as a VHF-FM-based radio communication system that has a range of up to 20 nautical miles (37 km) along most of the U.S. shoreline.
HF's position in the electromagnetic spectrum.. High frequency (HF) is the ITU designation [1] for the band of radio waves with frequency between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters (ten to one hundred meters).
With a low power home station and a simple antenna, range would be around 50 km (30 miles). With a large antenna system like a long yagi, and higher power (typically 100 watts or more) contacts of around 1 000 km (600 miles) using the Morse code (CW) and single-sideband (SSB) modes are common. Ham operators seek to exploit the limits of the ...