FRT-39 Series Transmitters
Technical Materials Corporation

When Technical Material Corporation made their popular GPT-10K transmitter to military specifications it was called the FRT-39. During its production run, three aditional variants were introduced as the product matured.

The Royal Canadian Navy procured the GTP10-K as the AN/FRT-39D.  Besides Coverdale, there were also examples of this transmitter at CFS Massett and CFS Bermuda.

FRT-39/GPT-10 photo and specifications courtesy TDP web site, Belgium. <>

Frequency range - 2 to 28 mHz
Power output: 10 kw PEP
Modes of operation: SSB, ISB, AM, CW, FSK, and FAX
Output power : 10,000 watts peak envelope power; Emergency : 1,000 watts
Frequency Control: Synthesized frequency control in 100 (cps) incremental steps
Keying: FSK : 75 baud (100 wpm) maximum 50v, 100v, 20 ma, 60 ma, all neutral, floating, or  either side grounded. 12 to 1,000 cps shift.
CW : 140 baud maximum.

Mains Power Input: 210-250vac, 50-60 cps, three phase,  approximately 50 amps/phase (20kw)
Operation at 390-480vac, 50-60 cps, three phase, approximately 25 amps/phase, was also available.

Here is a short chronology of the AN/FRT-39 development:

Radio Transmitting Set, HF, 2-28 MHz, 6 bands, 1 channel. A 5,000 watt
band switched transmitter used for fixed plant, point-to-point,
ground-to-air and shore-to-ship comm. Primarily designed for SSB
operation but may also be used for CW, FS, DSB, AM, MCW and SS
suppressed carrier.

Interchangeable with the AN/FRT-39 except for output power raised to 10
KW and it has a 7.5 kHz audio bandwidth in lieu of a 3 kHz bandwidth.

Synthesized sideband excitation added.

Oscillator-Power Supply group improved.

Oscillator improved.


1) EricEarl,  KG4OZO Atlanta  <eearle(at)>
2) Military List Equipment Page
3) TDP web site, Belgium. <>

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July 18/06