Ian Ropper GM0UHC drew an attendance of 24 for his talk on 27th April on the restoration of the classic Marconi WWII RAF R1155 Receiver & T1154 Transmitter as used in the Lancaster bomber and other aircraft. Visitors from the Livingston & District Amateur Radio Society and from the Museum of Communication in Burntisland were particularly welcome.
Ian described the problems in restoring this equipment, now about 70 years old: the rubber insulation on connecting wires just cracks off; electrolytic capacitors have dried out; resistors are unreliable. The equipment must be stripped down to the plain chassis, complicated by the fact that the various parts of it were spot-welded rather than bolted together. Lettering on the front panels just flaked off when cleaning was attempted, requiring re-painting and re-lettering. Ian installed modern electrolytic capacitors inside the cans of the now-unobtainable original capacitors to preserve the appearance of the equipment, and all the resistors were replaced. Parts such as the PT15 pentode PA valves were purchased via E-Bay.
Ian demonstrated his working equipment which generated much interest from the crowd.
Ian's website will shortly have a section on his T1154 restoration, in addition to his existing pages on Racal RA17 / RA117 restoration: http://www.chavfreezone.me.uk/
Photographs by Ian Ropper GM0UHC, Peter Dick GM4DTH and Alan Masson GM3PSP:
The excellent attendance of 24 filled the room.
The working equipment demonstration. In addition to the R1155 and T1154 (centre),
Ian also showed the dummy load (left) and his home-built power supply (right).
In the aircraft, power was provided via dynamotors.
Schematic of the entire system in a Lancaster bomber.
One enthusiast built an entire Lancaster mock-up in his attic.
Ian's R1155 and T1154 equipment.
Ian's R1155 receiver is identified as an AD8882B, possibly a prototype.
Front of Ian's T1154 transmitter.
Melvyn GM4HYR and Mike GM8KCS examine Ian's restored T1154 out of its case.
Ian GM0UHC takes questions after his talk.