Astre Systems, Inc.

Headlines

(reprinted from October 1990 TELEVISION BROADCAST)

Chinese Broadcaster Buys Astre Rig

MODESTO, CA--Astre Systems here has delivered its first UHF TV transmitter to the People's Republic of China. The 30-kW transmitter, operating in the PAL-D/K format, went on the air in August, 450 miles northeast of Beijing.

Liaoning, China

The Liaoning Broadcast and Television Tower, said to be the sixth largest
structure of its type in the world, looms over the province of Liaoning
in northeastern China. Astre has installed a new transmitter at the site.

The transmitter includes two complete exciters and two identical klystron amplifiers, each capable of 30 kW output. A special waveguide diplexer arrangement allows either klystron to quickly supply about 18 kW multiplexed in the event of a problem with either klystron. The changeover is typically less than 30 seconds and can be done remotely.

The PAL-D/K format, a 625-line, 50-Hz system occupying 8 MHz of bandwidth, posed some special problems in the design of the transmitter. But before shipping, it was powered up in the Modesto Astre facility.

The Astre Systems transmitter is the first U.S.-made transmitter to be used in the Liaoning Broadcast Center in the province of Liaoning. Four VHF and three UHF channels operate from the facility, which includes a 1,000-foot steel and concrete tower. It's reportedly the sixth tallest structure of its type in the world, covering an ADI of over 7 million people.

The Astre transmitter operates on channel K-15 or 486-494 MHz, and it shares the topmost antenna on the tower with channel K-21