FEBC’s Bocaue, Philippines TX Site

FEBC International Association uses a short wave transmission site owned and operated by local affiliate FEBC, Philippines in Bocaue, Philippines. This site has been in use since the 1950’s and was completely renovated with new transmitters, new antennas and a remodeled transmitter building between approximately 1998 and 2003. With a smaller sister site in Iba, Philippines FEBC broadcasts 42 hours a day of Gospel programming to SE Asia and China. This page describes the facilities and equipment.

Bocaue Antenna Selections

TCI Antenna Array
4 TCI HRS Antenna Arrays target (L to R) China, Myanmar, SE Asia and Indonesia

The workhorses for the Bocaue site are the 4 massive TCI antenna arrays. These are square arrays of broad band dipoles in front of a reflecting screen that form a focused “beam” of short wave radio energy. The arrays are arranged to point generally to China, Myanmar, SE Asia and Indonesia. Each beam can be steered +/-15 or +/- 30 degrees from the center to further target desired listeners. Each antenna has a switch that allows half to be used which provides a wider horizontal pattern when needed to cover a selected area of the world.

Schematic of a single HRS 4/4/.5 Antenna Array
Areas of the World that can be Reached by Bocaue TX Site

The Antennas at the site are technically HRS Type which means horizontally polarized, reflectorized and steerable (electrically). Pictured at far left is an HRS 4/4/.5 antenna which is the type we use for China and for Indonesia. The blue wires are the 16 dipoles arranged 4 across and 4 down. The reflector screen is obvious behind the dipoles. The antenna parts on the ground feed the radio signal in and provide for the electrical steering of the antenna. The China antenna is an HRS 4/4/.5, the antenna for Myanmar is an HRS 4/4/.7 which is higher above ground in order to radiate farther from the station. The SE Asia antenna is an HRS 4/2/.5 to provide a deeper pattern for good coverage of all of SE Asia. The Indonesian antenna is another HRS 4/4/.5.

Each antenna is just under 300ft tall and a littler wider. It’s almost impossible to get a good picture of them against the sky. The photos below show some of the parts of the antenna, the pattern switching gear, the giant “curtain rod” that suspends the antenna like a sail, the counter weights that are connected to the curtain rod by a pulley at the top of the tower and some of the FEBC team who ran the project to build them.

Bocaue Transmission Lines

The transmitter building at Bocaue is located almost 1/2 a mile away from the antennas. This is due to how the site developed historically and to the fact that the antennas themselves sit in the middle of an area of fishponds. FEBC designed, built components for and erected the transmission lines and the steel and concrete structures and poles that carry them. Sites like this one are not common in the world so the transmission lines are not off the shelf. The whole facility is designed to survive major typhoons (hurricanes in the western hemisphere) so everything is big, heavy and strong. For the technically inclined these lines are 300 ohm balanced lines made from 4 strands of #4 solid copper wire. Below are some pictures of the structure and lines including some during construction to give an idea of how big everything is.

The Switch Bay

The five transmitters in Bocaue are arranged through the switch bay so that any transmitter can drive any antenna. This allows flexibility if there is a need for service that stretches into the broadcast time. The switches are normally operated by compressed air as ordered by the computerized automation system which chooses the antenna/transmitter connection and the antenna steering and pattern choices based on a broadcast schedule that is edited by our staff.

Transmitter and Control Room

Bocaue has 5 Continental 418 series F transmitters. They are very efficient, requiring around 150KW of electrical power in to produce 100KW radio signals out. The transmitters they replaced took up to 250KW of electrical power to supply the same output signal. Today the transmitters cost about $1 per minute to operate, so shortwave broadcast isn’t cheap. The site is also home to radio DZAS a 60KW AM radio station covering central Luzon in the Philippines including metro Manila.