Whilst some pieces of Air Ministry electronics from the ‘40s are well documented and occasionally seen up for sale, others, such as this Test Set 43, are almost unheard of. When we received this oscilloscope, it was in a heavily modified condition and had to be rebuilt from the ground-up. Like many other sets of this type, the cathode ray tube is the well-known VCR138; fortunately surviving in good working order as you see here.