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RECEPTION SET (AUST.) NO. 8C

The Reception Set (Aust.) No. 8C was made in 1950 for use in the Wireless Set No.153, a 300 watt HF Transmitter and Receiver station. The WS. No. 153 was made by AWA and the Reception Set (Aust.) No. 8C shows a close resemblance to the AMR100/101 receiver of WW2. It uses similar plug in coil boxes and a 4 gang tuning arrangement, like the AMR100, HRO and AR7.

Two of the receivers were supplied as part of the WS. No.153, one situated next to the transmitter whilst the other was normally used at a more remote location. The WS. No. 153 could be used in a fixed location or mobile in the Army 4x4, ¼ ton truck.

The receiver was designed for reception of Telephony, CW and MCW. The audio signal was available through a small in-built monitor speaker and at two 600 ohm line jacks.

The frequency range was continuous from 1.85 Mc/s to 26 Mc/s in four bands. Plug in coil units covered the bands as follows:

Figures for sensitivity and selectivity are not provided in the manual but would be similar to the other sets of the period and purpose. It was fitted with a crystal filter with provision to vary the selectivity and neutralization. The IF was 455 Kc.

The set included an integral power supply operating from 100, 110 or 120v or 200, 220v or 240vac at 50 to 60 cycles. Power consumption was around 70 watts. It also included a vibrator for operation via 12v dc batteries. As a safety measure the ON-OFF switch was interlocked with the input voltage selector so that it had to be switched off before changing voltages.

The case of the Reception Set (Aust.) No. 8C was therefore of similar height to the AMR100 but much wider, to accommodate the speaker and power supply. It was fitted into a heavily ribbed sheet aluminium case shock mounted within a tubular carrying frame that formed part of the mobile installation frame for the overall equipment. A ribbed aluminium front cover was clamped on, with a sealing gasket to aid water resistance.

The set alone weighed 74 ¾ pds (34 Kg) and was 28” wide x 13 ½” deep x 10 ½” high (711mm W x 343mm D x 267mm H). When fitted into the carrying frame it weighed 93 ½ pds (42.5 Kg) and was 31 ¼” wide x 18 ½” deep x 15” high (794mm W x 470mm D x 381mm H).

This shows the complete WS 153 in its waterproof cases and Carry Frame. At the top left is the case containing the major and Minor Rectifier Units that provided LT and HT to the Transmitter and Receiver. On the right is the case for the Radio Frequency Unit, the transmitter. The Reception Set (Aust.) No.8C is in the case underneath. Not shown is a curious cylinder housing the operating controls and mounted with the plugs and sockets for the interconnections between the various items.

The receiver had nine valves plus two rectifier valves and a vibrator, The chassis also carried a spare vibrator. They were all fitted with clamps to prevent them working out of their bases. The valve line up was as follows:

                        V1A                 6U7G               1^st RF Amplifier
                        V1B                 6U7G               2nd RF Amplifier
                        V2A                 6J8G                Mixer
                        V1C                 6U7G               1^st IF Amplifier
                        V1D                 6U7G               2^nd IF Amplifier
                        V3A                 6G8G               2^nd Detector, AVC and 1^st Audio Amplifier
                        V4A                 6V6G               2^nd Audio Amplifier
                        V5A                 6J5G                Local Oscillator
                        V5B                 6J5G                BFO
                        V6A                 6X5GT            Rectifier
                        V6B                 6X5GT            Rectifier
                        V181A             VS123             Vibrator

It seems unusual to use such old valves in a 1950's set but the specifications would have been written and the design commenced not long after WW2 when such valves were current.

RECEPTION SET (AUST.) No. 8C

The aerial could be a doublet, or single wire and earth and there was also a socket for a co-axial cable.

The tuning was arranged with the same style of tuning gang and reduction drive as seen in the HRO, AR7, and AMR100.

The controls across the front panel were, from top left:

AERIAL and EARTH.

CO-AXIAL FEEDER for a 70 to 80 ohm cable.

RED PILOT LIGHT to indicate power on or off.

SELECTIVITY CONTROL.

DC 10 AMP FUSE in the 12 volt supply leads

AC 3 AMP FUSE in the 110/240 volts supply line.

HT 250ma FUSE in the HT line.

Back to the middle left the controls are:

AF GAIN

600 OHM LINE JACK (2) for either headphones or a remote audio feed.

MUTING JACK. The set could be muted remotely from the Wireless Remote Control Unit H (Aust.)

AERIAL TRIMMER

MAIN TUNING DIAL

RF GAIN

CRYSTAL SWITCH

SELECTIVITY SWITCH

PHASING CONTROL

SPEAKER SWITCH to turn it on or off.

ON-OFF SWITCH. The main power switch.

AC INPUT PLUG. The spring loaded cap was painted blue. The WS 153 used colour coded connectors on the numerous interconnecting cables cables to prevent mistakes. The primary receiver was normally powered with ac via the WS 153 but the remote set could be powered from ac mains of batteries depending on location.

DC INPUT PLUG for Connector 3 point (Aust.) No. A.9.

Then across the bottom of the panel are:

BFO CONTROL.

PLUG IN COIL RECEPTACLE.

FACILITY SWITCH. This is a 4 position switch 1) HT off but heaters on, 2) On with AVC on, 3) On but AVC off, 4) BFO on.

LAMPS OPERATOR. 12 volt leads could be connected to these two terminals for a Lamp Operator’s No. 8 (Aust.)

POWER SELECTOR. A 3 position switch for 110v, 240v or 12 v dc.. As indicated above it is interlocked with the On-Off switch to prevent accidents.

EARTH. An alternate earth terminal.

The 3 spare band coils were housed in a metal case with a waterproof lid and a carry handle.

The construction of the receiver was conventional but special effort was made to keep it moisture free. All control shafts had rubber seals and the speaker had a plastic sheet protector. The chassis bolted into the case with a rubber sealing gasket round the periphery. The lid also had a rubber seal so that the set was immersion proof. The lid held a canvas flap that could be attached over the receiver to keep water off it.

References.
(Z1/ZAA 3088) User Handbook for the RECEPTION SET (AUST.) NO. 8C. 1950

Please note, this article is copyrighted.

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