Talking about the application of Motorola walkie-talkie in large-scale activities
One of the distinctive features of modern large-scale performances is the large scale, the participation of many performances and technical departments, the complicated command and coordination relationship, and the large traffic. The requirements for the function, reliability and real-time of the communication system are higher than in the past. For substantial improvement, it is necessary to establish a high-tech, high-standard, reliable, high-efficiency, high-security, and fully-functional communications command and dispatch system. Motorola walkie-talkies have successfully guaranteed the normal operation of communication systems for countless large-scale events. Now I will give a brief overview on some of the key issues of the 60th National Day celebration party.
1. System structure
There are many aspects of the internal communication system in large-scale performances that need to be guaranteed, including the chief director and executive director's chief command system, the internal communication system of various technical, production, performance, and logistics teams. The command system of the performance department and the broadcasting system to the actors. A comprehensive platform involving wired systems, wireless systems and broadcasting systems. Therefore, the common practice is to use a matrix call system that can integrate wired and wireless systems as the basis. In this, each wired and wireless sub-system is connected to the call matrix through different interfaces and interface devices, and the cross-connection relationship of each input and output port of the matrix is controlled by the computer. The matrix system is a four-wire system. Generally, a main matrix is set up to manage the main wired and wireless interfaces. In order to ensure the reliability of the system, the dual-fiber ring network redundancy design must be adopted in the multi-matrix design. Its advantage is that the operation of the entire system will not be affected when one connection line fails.
2. System functions and design points
The internal communication system composed of the above-mentioned network can integrate all wired communication systems, wireless communication systems and broadcasting systems very flexibly and conveniently, realizing wired and wireless conference calls, point-to-point calls, broadcasting, multicasting and other calling functions, through the Olympic Games The practice of the opening and closing ceremonies proved that this design can fully meet the needs of modern large-scale performances and is very convenient.
Among them, the wired system is mainly the dispatch panel and the Party-Line system. The dispatching panel can easily integrate multiple communication channels on one panel, which is very convenient for system commanders, such as the executive director of the show, the main operators of the lighting, sound, stage machinery and other departments. In addition, for the executive director's panel, the communication channels should be concentrated as much as possible. The principle is to use the least channels to call all those who need to receive instructions. In the use of the Party-Line system, it is found that it is best for a party-line line to have two independent channels, because most fixed-position operators need to hear the command password of the system, and also need to hear the instructions of the executive director to judge During the performance, you may need to listen to the music with cue on the scene to prepare your own actions in advance. This is also very critical. Almost all Party-Line users require the use of dual-channel bodypacks when guaranteeing the opening ceremony of the Olympic Games.
The wireless system mainly includes ordinary single-duplex walkie-talkie, wireless duplex pocket and third spinning system cluster access. Ordinary analog walkie-talkies are widely used in large-scale performances due to their convenient use and quick calls. The Beijing Olympics and the 60th National Day Gala both used Motorola professional walkie-talkies. The opening ceremony of the Beijing Olympics used about 1,000 Motorola walkie-talkies, and the 60th National Day Gala used nearly 1,300 Motorola walkie-talkies. Analog walkie-talkies are widely used, covering all work positions with a few calls, and require high equipment performance. It is required to have enough working time and communication distance, and also have high requirements for the waterproof and dustproof of the equipment. Motorola CP1300/CP1660 all meet the above requirements, especially the reliability and endurance of the equipment.
Using the corresponding transmitting and receiving base station equipment can access the analog wireless channel used by mobile users into the internal communication system. The usage mode is divided into the simplex mode of sending and receiving the same frequency (Figure 1) and the half-duplex mode of sending and receiving different frequencies. The single rainbow mode is simple and convenient. The call between the people can be connected to the internal communication matrix system but does not depend on the base station equipment. The half-duplex mode is for the wired system call intercom users, the working mode is the duplex mode, and no copper time is generated. The wireless conflict during speech is more conducive to the use of higher-level commanders.
The simplex mode base station equipment transmits and receives at the same frequency, it is necessary to set up a switching mechanism to ensure that the same frequency receiving module is turned off when the transmitting antenna is working.
3. Aspects that should be paid attention to in actual operation
In the actual operation of the system, there are many problems that need special attention.
In large-scale events, wireless frequency resources are crowded. As a command communication system for performances, a large number of wireless channels are generally required. For example, at the opening ceremony of the Beijing Olympic Games, the number of ordinary analog intercom channels reached 56, and the number of National Day 60th anniversary party reached 45. In the case of a half-duplex system, each individual channel requires two frequency points. With such a large number of frequencies, considerable effort must be spent on intermodulation interference between frequencies, especially third-order intermodulation interference. You need an experienced wireless engineer to apply for a frequency without intermodulation interference through scientific calculations, and at least ensure that the frequency you apply for will not interfere with your own system. In addition, it is necessary to monitor one's own working frequency spectrum to find out all kinds of external interference at any time and eliminate it in time.
Since the wireless system is connected to the internal communication matrix system through the access device, it is very convenient to integrate the wired system and the wireless system through programming.In addition to the scheduling panel, the wired Party-Line bodypack can also connect one of them or All channels are connected to the wireless intercom channel.