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Military Microwaves Supplement
LBA Technology has designed, built and delivered to Taiwan an advanced technology medium wave triplexer system for the Broadcasting Corp. of China (BCC). This is the second successful multiplexer project undertaken by the North Carolina company for the BCC.
The project is especially notable because the tower site posed an engineering challenge. The triplexer had to be incorporated into an electrically short tower in the middle of a lake, with the tower base and triplexing equipment fitted snugly on a small platform area 30 feet above the water.
Half a world away from Taiwan, LBA senior engineer Marvin Brewer simulated the electrical requirements by NEC modeling. He specified installation on the tower of an LBA Technology Q-Cage™ broadbanding kit to improve matching impedances and then designed a triplexer system in three independent ATU – RF filter combinations. The system’s weatherproof cabinets were clustered around the base of the tower base in a way that allows full access to them for maintenance. LBA Technology shop experts fabricated, adjusted and tested the entire system.
A triplexer allows the simultaneous use of three medium wave AM transmitters on a single antenna. Triplexers combine an antenna-tuning unit and a rejection filter section for each frequency, which effectively sort out and pass through desired frequencies and reject undesired frequencies. The triplexer system for BCC was designed for 531, 648 and 963 kHz, and 10,000 W power at 125 percent modulation for each frequency.
The triplexer system was delivered through Broadcast Electronics in Quincy, IL, an international transmitter manufacturer. LBA has partnered with the Illinois company on projects in the US, the Middle East, Far East Asia, Afghanistan, Iraq and the United Kingdom.
LBA Technology routinely custom-engineers multiplexers so broadcasters can feed multiple transmitters to common antenna systems. It is a cost-effective way to minimize the physical plant requirements of AM broadcast stations. With almost 50 years of experience, LBA provides a wide variety of AM broadcast antenna solutions for all power levels worldwide.
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