RCA BHF-100B

GENERAL DESCRIPTION

BHF-100B High Frequency Broadcast Transmitter

photo RCA BHF-100B

GENERAL

The RCA Type BHF-100B 100 KW Shortwave Transmitter is designed for high-fidelity radio-telephone transmission in the International Broadcast bands. Continuous coverage of the frequency range from 93.7 meters (3.2 megacycles) to 11.5 meters (26.1 megacycles) is provided through band-switching. The transmitter employs a high-efficiency type of phase-to-amplitude modulation.

All r-f and modulation components are housed in four equipment cabinets and an exciter / modulator assembly. Except for a cabinet located in a rear area. Floor area requirements for transmitter installation have been kept to a minimum while providing adequate work space and free access to components. The entire transmitter, complete with input equipment and an accessory control console, can be housed easily in a building 6.7 meters (22 feet) by 9.1 meters (30 feet).

The BHF-l00B has many built-in reliability and protective features.

Ample cooling is provided for all r-f and modulation components by a 244-cubic meter per minute forced-air system supplied by a single blower external to the equipment cabinets.

All necessary power distribution and switchgear equipment from the point at which the 380/460-volt, three-phase power enters the system is supplied as part of the transmitter. Full d-c and a-c overload protection is provided throughout. Door and panel interlocks are used extensively to protect operating personnel.

For reliability, all power supplies use silicon rectifiers operating well below their maximum ratings.

Designed for use with or without a control console, the transmitter may be controlled remotely by the addition of the BTC-1B Control Console Equipment listed in the EQUIPMENT LIST. Provisions have been made in the transmitter wiring for remote control operation.

CONSTRUCTION

The cabinets which house the transmitter r-f, modulation, and control components are aluminum; the cabines bases are steel. All components in the cabinets are accessible for maintenance and servicing through full-length doors or through panels secured to the cabinets with quick-release fasteners. Wiring interconnections among these units are made by individual cable runs through a special duct installed on top of the cabinets. The power-distribution equipment is floor- and wall-mounted. All high-voltage a-c and d-c cable runs are made through conduit or wall-mounted square ducts. The location of the major components or associated group of components in the transmitter cabinets is shown in figure 2. All doors and panels that provide access to areas containing high voltage are interlocked. Any of these interlocks will remove high voltage and also will automatically ground the high-voltage d-c output circuits. Convenience outlets for 110-volt a-c power are installed in the control and distribution unit and the rack-panel assembly housing the exciter/modulator, drive regulator, and power supply unit for use with 110-volt test equipment. An external stepdown transformer must be supplied, if 220-volt building service is all that is available. Compartment lights are provided in the control and distribution unit for ease of operation and maintenance of the control components.

photo RCA BHF-100B

TUBE COMPLEMENT
RF stages		AF stages and modulator		Rectifiers
Number	Type	Number	Type	Number	Type
4	ML-6697
4	4CX10000
4	7094

THIS TYPE OF TRANSMITTER IS INSTALLED IN THE FOLLOWING COUNTRIES
	ITU	Country	ITU	Country
	EQA	ECUADOR	PAK	PAKISTAN
	PLW	PALAU	USA	USA
	CVA	VATICAN CITY