Inside a WW2 RAF R1224A Battery Superhet: Mazda Octals, Muirhead Dials and No Serial Number

While rummaging in my other storeroom I came across my two RAF R1224A receivers. They're five-valve battery superhets from about 1941–42 covering 1 to 9 MHz in three bands, used at airfields, and they're an odd mix: a Muirhead slow-motion dial, a reaction control on a superhet (cheaper than a BFO), grid bias batteries like a 1920s set, and a valve line-up of 1930s domestic types, metallised Mazda octals and a British 7-pin frequency changer. It looks like they built it from whatever was to hand. One set has been worked on (by me, years ago, I think). The other is 100% original, varnished, perhaps tropicalised for the Far East, and has no serial number at all. Was it ever issued? I take the first one out of its case, pull the valves (with a story about Mazda octals from when I was 15), and look at the coil pack, the stores numbers on everything, and underneath the chassis. Next time: a battery eliminator and getting it going. In this video: 0:00 The best bits 0:25 Two RAF R1224A receivers 1:16 Stores numbers and the front panel 3:42 Tuning ranges: 1 to 9 MHz 4:30 A wartime odds-and-ends valve line-up 6:01 Batteries and grid bias 6:41 The second set: tropicalised? 9:38 No serial number: never issued? 10:53 Out of its case: the Muirhead drives 11:46 Pulling the valves 14:02 Mazda octals: a lesson learned at 15 15:38 British 7-pin and the frequency changer 17:01 Stores numbers, IF transformers and the trimmer 17:48 The output transformer 18:50 The coil pack 20:16 Underneath the chassis 21:27 Reaction instead of a BFO Do you know more about the R1224A, its companion transmitter, or the 10D/13047 vs 10D/13074 reference numbers? There's very little published on these, so please share in the comments. Military receivers playlist: (add a "Military receivers" or "From the collection" playlist link) The VCR139A 405-line TV project: https://project405.co.uk #R1224A #militaryradio #RAF #ww2 #vintageradio #valveradio #boatanchor