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RECEPTION SET No. 1 (AUST.)
Sketch from Provisional Handbook
The Reception Set No.1 (Aust.) was a special communications receiver designed for interception reception in special Wireless Sections and for general communications within and above Corps. on CW and MCW telegraphy (W/T), and Radio Telephony (R/T). It covered a frequency range of 138 to 410 Kc/s (2174 to 731 metres) and 495 Kc/s to 25 Mc/s (606 to 12 metres) using 6 plug in coils to cover the range..
NOTE that the Reception Set No.1 (Aust.) was adapted from the Kingsley Radio KCR/11 that was used by the RAAF as the AR7.
A separate power supply was provided which allowed the receiver to operate from either 230-240v ac, from mains supply or a petrol generator, or from 12v dc provided by two 6 volt 150 ah. secondary batteries. The current consumption on ac was 0.32 amps at 230v. On dc it was 4.75 amps. The Power Supply had a 3 position switch on the front: 12VDC - OFF - 230VAC.
The IF was 455 Kc/s. The selectivity with the crystal filter off was:
6 Kc/s off resonance
20 db down
At ± 12 Kc/s off resonance -- 40 db down
At ± 18 Kc/s off resonance -- 60 db down
|RECEIVER||79 Pds. 35.9 Kg||29 1/8" 740 mm||11 7/8" 302 mm||13 7/16" 342 mm|
|POWER UNIT||40 Pds. 18 Kg.||22 1/8" 562 mm||8 1/8" 206 mm||8 5/8" 219 mm|
|TWO BATTERIES||66 Pds. 30 Kg.||73 3/4" 1873 mm||10 1/2" 267 mm||10 3/4" 273 mm|
|SPARE VALVES||8 1/2 Pds. 3.9 Kg.||10" 254 mm||9" 229 mm||7 1/2" 191 mm|
The receiver used the following valves:
V1 6U7G 1st RF Amplifier
V1B 6U7G 2nd RF Amplifier
V2A 6K8G Mixer - Oscillator
V1C 6U7G 1st IF Amplifier
V1D 6U7G 2nd IF Amplifier
V3A 6G8G 2nd Detector - AVC AF Amplifier
V4A 6C8G BFO and Meter
V5A 6V6G AF Output
V6A 6X5GT Half Wave Rectifier
V6B 6X5GT Half Wave Rectifier
V1B1A Vibrator (Rectifier KRC11)
The manual notes that if either the 6U7G or 6K8G valves were replaced, the set should be returned to the ordnance workshops for realignment.
The aerial was arranged to accept either a doublet or a single wire and earth. At the rear of the case there was a compartment covered by a sliding lid. Inside the compartment were terminals marked A1, A2 and E. A1 and A2 were used with a doublet whilst a vertical aerial would be connected to A1 with an earth connected to E and A2 jumpered to E.
The tuning was accomplished by a large vernier dial as used on the HRO, AR7 and AMR100/101 style of receiver, driving a 4 gang capacitor.
The IF frequency was 455 Kc and the set had a Crystal filter.
FROM SKETCH OF No.1 IN PROVISIONAL MANUAL
The front panel controls were as follows - from top left:
SIGNAL "S" METER.
On the second row:
AVC/BFO SWITCH. A toggle switch that switched off the AVC and applied the BFO signal when switched to BFO.
"S" METER ADJUST to set the "S" meter to zero.
SELECTIVITY used when the crystal filer was in circuit.
CRYSTAL IN-OUT. A toggle switch marked IN-OUT.
PHASING. Used to adjust the phasing of the crystal when in circuit.
On the bottom row:
RF GAIN with PHONES No.1 SOCKET below. If headphones were plugged in the speaker was muted.
COIL BOX RECEPTACLE
AUDIO GAIN. In the anti-clockwise OFF position the set was on STAND BY. The HT was switched off but filament voltage remained applied to the valves. PHONES No.2 SOCKET below, which did not mute the speaker..
The construction of the set was identical to the AR7, with a sheetmetal chassis, reinforced by spotwelded gussets. The whole was copper plated for low electrical resistance and then cadmium plated for corrosion resistance. The Power supply was similarly fabricated. The 3 position switch on the Power Supply is the same as for the AR7, a 19" rack mount version..
The Reception Set No.1 Power Supply.
(courtesy of Chris Gill)
The No.1 set differed from the AR7 in that it was fitted into a drip proof metal case with compartments either side to hold the spare 4 coil boxes. (The set was issued with 6 coils, A to F. With one in the receiver and two either side in the compartments, where was no. 6 stored?) A sheet metal lid enclosed the set and coil compartments, with clips to hold it in place. The lid carried the headphones. As detailed above, the connections for speaker, 600 line and aerial connections were made in a compartment set into the rear of the case, and protected by a sliding metal cover. Flying leads connected between the terminal block and the set itself. There was a hole to allow the power lead socket to plug directly onto the power plug on the rear of the receiver. The set could be withdrawn part way from the case to replace valves but to remove it completely, firstly screws holding the rear panel of the case had to be removed to free that panel, then the wires could be disconnected.
The case and lid of the No.1 were painted Khaki green No.3. However, there are reports of some being painted black and others are silver like the RAAF AR7.
Spare valves, fuses etc were carried in a Case, Valve and Receiver, No.2.
All the components of the Reception Set No.1 were allocated Army part numbers and nomenclature such as "ZAA337, Condensers Variable, No.27 (Aust.)", etc.
Provisional Pamphlet, Reception Set , No. 1 (Aust.) Also called Provisional Handbook. Reception Set No.1 (Aust.) 23 Dec. 1942.
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