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An ICOM IC-7300 Radio Tuned to the 20 Meter Band. The ICOM IC-7300 is a multimode 6 meter, 4 meter (ITU Region 1 only) and HF base station amateur radio transceiver. [1] The IC-7300 was announced to the public at the Japan Ham Fair in 2015. [2] The radio has 100 watts output on CW, SSB, and FM modulations and 25 watts of output in AM. [3]
Morse code is called the original digital mode. Radio telegraphy, designed for machine-to-machine communication is the direct on / off keying of a continuous wave carrier by Morse code symbols, often called amplitude-shift keying or ASK, may be considered to be an amplitude modulated mode of communications, and is rightfully considered the first digital data mode.
Aurorae only occasionally affect signals on the 2 metre band. Signals are often distorted and on the lower frequencies give a curious "watery sound" to normally propagated HF signals. Peak signals usually come from the north, even if the signal originates from a station to the east or west of the receiver.
One of the first challenges faced by amateurs implementing packet radio is that almost all amateur radio equipment (and most surplus commercial/military equipment) has historically been designed to transmit voice, not data. Like any other digital communications system that uses analog media, packet radio systems require a modem.
The D-STAR open radio system was developed by Icom based on digital radio protocols developed by the Japan Amateur Radio League and funded by the Ministry of Posts and Telecommunications. [6] This system is designed to provide advanced voice and data communications over amateur radio using open standards.
Cancelling a local transmit signal requires a combination of analog and digital electronics. The strength of the transmit signal can be modestly reduced before it reaches the receiver by using a circulator (if a shared antenna is used) or antenna isolation techniques (such as cross polarization) if separate antennas are used.
There have been several system improvement programs, including the Integrated Communications Security (ICOM) models, which have provided integrated voice and data encryption, the Special Improvement Program (SIP) models, which add additional data modes, and the advanced SIP (ASIP) models, which are less than half the size and weight of ICOM and ...
Systems that use NXDN also support mixed analog FM and digital NXDN equipment, including direct radio-to-radio communications. This allows system owners to migrate to a narrowband, digital system without replacing the entire system at once. NXDN equipment is currently FCC type-accepted for use on VHF (137-174 MHz) and UHF (406-512 MHz) bands.