200PT (1A and !D) SPECIFICATIONS:

Basis CW transmitter: 200PT-1A
Frequency Range: 1500 to 6300 KHz in five bands.
Power Input  as a CW transmitter only  - 100 watts.
Power  Input  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 transmitter held by the Vancouver Marine Museum.  (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.

200PT-1D PLATE MODULATOR
Type 53796 and 53796H

In the field, the modulator is easily retrofitted to the 200D transmitter using Marconi's  kit # 93796
When used with the 200D transmitter, the following characteristics are  observed:

* Audio output: 250 watts.; Class C telephony.
* Frequency response: +/- 2db from 200 to 500 cps.
* Noise Level:  45 db unweighted below full modulation.
* Distortion: At 75% modulation, distortion  is below 10%.
* Audio Input: Modulators suffixed with the letter H means they can operate from a 500 ohm telephone line.
* Mains power: 115 VAC 25 or 60Hz, 500 watts

DIMENSIONS
Height - 33 5/8"
Depth - 16 "
Width - 19 3/8
Weight: 275 pounds

TUBE LINEUP
First audio               1x 6C5
Modulation driver   2 x 6L6
Modulators             2 x  6C5
LT rectifier              1 x 5Z3
HT rectifier              2 x 866

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Contributors and Credits:

1) Guy Mathias Vancouver Maritime Museum Curator   <collections(at)vancouvermaritimemuseum.com>
2) Peter Anderson
3) John Gilbert

Nov 1/25