1.RADIOTELEX COMMUNICATION

1.1General

Telex subscribers can attest to radiotelex as a reliable and efficient method for sending and receiving teleprinter connections. Telex subscribers, especially those who often use HF-band radio circuits, will also attest that the telex connection is subject to interference from a variety of sources, including atmospherics, fading and noise disturbance. This interference plays havoc with radio signals, re- sulting in the receiving of information different from the intended information. Thus a means must be provided to prevent mutilation of radio signals by interference on HF-band radio.

Radiotelex communication today owes its reliability and efficiency to error detection and correction. The ITU-R defined both a con- stant-ratio code for automatic error detection and requirements for the error correction in Recommendation 476-3.

1.2 Code Description

The DP-6 employs a 7-element synchronous code providing 27 = 128 combinations. Among these 128 combinations, there are 35 constant-ratio combinations having a ratio of 3 (Y) mark bits to 4

(B)space bits. Thus ratio is used to test the validity of each re- ceived character.

Of the 35 combinations, 32 are used for the required alphanumeric teleprinter signals. The remaining three 7-element codes are used exclusively for operational purposes. These are:

Idle Signal α (ARQ Mode), Phasing Signal 1 (FEC Mode)

Idle Signal β

RQ Signal (ARQ mode), Phasing Signal 2 (FEC Mode)

Transmission rate is 100 bauds. If the 4B/3Y ratio is disturbed due to interference, the output of the receiver is blocked to restrict the mutilated character from passing on to the teleprinter.

Frequency Shift

The frequency shift is 85 Hz with a center frequency of 1700 Hz, as specified in ITU-R Recommendation 476-3.

Space Tone Frequency1700+85 = 1785 Hz

Mark Tone Frequency 1700-85 = 1615 Hz

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Furuno RC-1500-1T manual General, Code Description, Frequency Shift
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RC-1500-1T specifications

The Furuno RC-1500-1T is a highly regarded radar system designed specifically for maritime applications, providing vessel operators with robust tools for navigation, collision avoidance, and situational awareness. With advanced features and cutting-edge technologies, the RC-1500-1T stands out as a reliable choice for both commercial and recreational vessels.

One of the main features of the Furuno RC-1500-1T is its high-resolution display. The system boasts a crystal-clear LCD screen that offers exceptional visibility, even in bright sunlight. This makes it easier for operators to monitor the radar’s output, enhancing their ability to detect and track other vessels and obstacles in the marine environment.

Another significant characteristic of the RC-1500-1T is its power and performance. The radar operates on a frequency of 9.3 GHz, providing a range of up to 64 nautical miles, depending on environmental conditions. This impressive range ensures that mariners can detect distant targets, giving them ample time to react and make informed navigational decisions.

The RC-1500-1T also incorporates Furuno’s advanced signal processing technology. This enhances target detection and discrimination capabilities, allowing users to differentiate between multiple targets in cluttered environments, such as busy harbors or areas with a lot of smaller vessels. This technology is especially crucial for ensuring safety while navigating.

Additionally, the system comes equipped with various operational modes, including different range scales and advanced filtering options. Users can customize their radar display to highlight specific target types, improving the radar's effectiveness based on situational needs.

Safety features are a vital aspect of the Furuno RC-1500-1T. It includes an Automatic Radar Plotting Aid (ARPA) function, helping operators track targets and predict their movements. This bolsters the vessel's ability to navigate safely, particularly in challenging visibility conditions.

Furthermore, the compact design of the RC-1500-1T makes it easy to install on a variety of vessels without taking up extensive space. Its robust construction ensures it can withstand harsh marine environments, making it a durable solution for long-term use.

In conclusion, the Furuno RC-1500-1T radar system combines advanced technology, user-friendly features, and high performance to provide mariners with crucial navigational information. Its capabilities cater to both experienced sailors and newcomers alike, reinforcing its position as a leader in marine radar technology.
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