200PT-1A  Transmitter and 200PT-1D Plate Modulator


Basis CW transmitter: 200PT-1A
Frequency Range: 1500 to 6300 KHz in five bands.
Power Output as a CW transmitter only  - 100 watts.
Power  Output as a Phone transmitter: 250 watts
Frequency control: Crystal is assumed since there is no VFO.

In order to use Phone, the transmitter  must first be field modified to output 250 watts.
The procedure for doing this is in the manual. New primary coils need to be installed in the final output stage. If ordered from the factory as a pair, , no modifications are necessary.

Modulator Assembly: 200PT-1D
Modulator output power 250 watts.
Modulation type: Plate
Maximum power consumption: 115 Volt,  60 Hz 9.5 amps

At the left is the Marconi 200PT with the LTT-4 transmitter on the right. Both are on display in  the radio room of the St. Roch, a historic RCMP patrol boat berthed as an indoor exhibit at the Vancouver Maritime Museum. (Image courtesy Vancouver Maritime Museum)

A close view of the lower portion of the 200-PT before it was repainted.. (Image courtesy Vancouver Maritime Museum)

This placard was found  to be affixed to the 200PT example held by the Vancouver Marine Museum. It is suspected that the numbers are referencing a photo of the unit in the equipment manual. Normally, the word INDEX would not be the title of  such a placard. The bottom two entries had to be changed from Higher to High and Lower to Low.   (Photo by John Gilbert)

The label on this 200PT manual suggests that the -!A is the RF portion of the transmitter. 
This  manual label suggests that the -1D was the modulator which was paired with the -1A unit. 

Contributors and Credits:

1) Guy Mathias Vancouver Maritime Museum Curator   <collections(at)vancouvermaritimemuseum.com>

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Dec 13/07