PTR-175 transceiver

Communication.

VINTAGE AVIONICS

PTR 175

PTR-175 transceiver, DC-only version

Photo E-bay

Plessey PTR 175 VHF/UHF transceiver

The British PTR-175 made by Plessey is an extension of the ARC-52. A VHF transceiver was added, and the channel spacing is 50kHz, both in VHF and UHF.

The inside and outside look the same as the ARC52 ; the plug, cables and control panel are identical. The “hundreds MHz” digit on the C 1607/4 control panel can be set to 1, 2 or 3, rather than only 2 or 3. On the inside, the relay module got more relays and three VHF local oscillators, and the RF preamplifier module got a complete VHF mixer and final amplifier, see this picture.

Versions

Like the ARC52, the PTR175 was available in a DC-only version with dynamotor, and in an ac version (PTR175A) with 3-phase 400Hz supply.

Support is available for the automatic direction finder ARA25, and for a variety of microphones. Even a limited intercom function can be configured. The guard receiver module can be replaced by an fsk demodulator for data transmission which changes the unit name to PTR177.

Frequency range

UHF 3500 channels with 50kHz spacing from 225.00 to 399.95 MHz, AM., 20W RF output.

VHF 370 channels with 50kHz spacing from 117.50 to 135.95MHz , AM, 3W RF output There are separate connectors for the VHF and UHF antennae.

The unit has 46 tubes and a few transistors in the VHF mixer and IF stage.

Diagrams can be found here