TH-41 Transmitter

The TH-41-B transmitter, is a high-power,  transmitter for ground fixed station used in long distance point-to-point communication. It consists of nine large cabinets containing the following: rectifier power supply, modulator, LF RF unit, four HF RF units, two RF exciter units and one separate remote control unit. Each RF unit con be operated on 10 preset channels (either crystal or master oscillator frequency controlled), except the LF unit which uses master oscillator frequency control only.

Three transmitting units can be operated simultaneously on either CW or FSK. When voice is used, only two units may be operated at a time (one unit modulated and the other on CW or FSK.
Complete remote control of all functions is provided by Master Remote Control Unit 141-398 from distances up to 5 miles over four pairs of standard telephone lines.

The transmitter RF units are designed to operate into a 600-ohm balanced or unbalanced transmission line; however, on L type matching section is included in the HF units to provide on impedance matching range of 70 to 2,500 ohms. The LF unit uses a T-type matching section for 72-ohm coaxial cable RG-34/U, or equivalent.


Frequency range: LF -  80 KHz to 200 KHz, single channel, master oscillator (MO) frequency control.
                               HF -  2 to 28 MHz; 10 preset channels  per RF unit. Either MO or crystal control
                                        may be used.

The Royal Canadian Navy used the TH-41 transmitter in its shore stations.  In 1963, these crystal frequencies were available for the transmiiter.

Power Output : 5,000 watts

Modes: CW,  FSK and  AM voice
Power requirements : 40.5 kva, 208/220 v, 3 phase, 60 Hz.
                                      250 w 115 V SIngle phase 60 Hz when MO oven heaters are used.
                                      150 additional watts when remote control equipment is used.

Dimensions: 125 in wide x 81 in high x 37.5 in deep.
Weight: 10,000 pounds. Ships in 15 packages.
Circa: June 1952

TH-41 (Photo courtesy Pinetree Line)

The complete TH-41 (Photo courtesy JPtronics Org)

TH-41 major components (Data courtesy JPtronics Org)

Contributors and Credits

1) Pinetree Line
2) JPtronics

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May 25/20