The SRT-502 was a replacement for the PV500 LM and PV500HM2. It was designed primarily for ship-to-shore or ship-to-ship communications. Included in the set, were two HF transmitters (3 to 28 MHz) for long distance work and one low frequency unit (100 to 550 kHz) for shorter distances. All three transmitters shared a common power supply. Modes of operation were CW, R/T and RATT, however, the LF transmitter was not designed for R/T operation and it also ran at a lower power level than its HF counterpart.

The high frequency transmitter was capable of producing a power input of 1000 watts in high power operation, or 300 watts in low power mode. Internally, the HF amplifier employed two 4-400A tubes in parallel, while the LF amplifier employed a pair of 4-125 tubes. Any two transmitters could be operated at the same time with high power input or alternatively, all three transmitters could be operated in low power mode.

This example of the SRT-502 transmitter is held by the MARCOM Museum, Halifax. The entire transmitter was designated #116-892 by Canadian Marconi.. (Photo by Sandy McClearn)

Nameplate photos by Tom Brent

Per BRCN 213, the following crystals were available for use with the AN?SRT-502. The highest SRT-502 serial number recorded thus far is #124.

Each of the three sections of the transmitter were provided with a customized TUNING and CALIBRATION CHART.When not in use, these documents were stowed at the very bottom of the transmitter in its own holder .This documentation provided information for VFO control.

This document was specific for HF#1 transmitter  aboard HMCS Chaudiere. (Via Tom Brent)

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Contributors and Credits:

1) Tom Brent

Aug 28/23