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Embarrassing "Dippings"

by Peter Tingey  (ex BBC Designs Department)

Having designed a receiving aerial unit UNl/163 I realised that the internal bundle of ferrite rods measuring 8 inches by 1 inches in diameter needed to be encapsulated into a solid block to avoid the shattering of the brittle ferrites if the unit was accidentally dropped. The rods, being fired at high temperature, are rough and misshapen so a rubber sheath rolled onto the assembly, filled with a solution of araldite and left to set, was the neatest solution. Normal condoms needed external support to avoid sagging when loaded with the araldite, so the London Rubber Company was approached and after sending them an aluminium model of the ferrite rod assembly, we received (at no charge) a quantity of extra thick sheaths now called dippings.  A normal condom is a single dipping into the rubber solution, these extra thick sheaths were multiple dippings to increase the rubber thickness. Using these dippings gave perfect encapsulation and after setting the dipping was rolled off, washed and used repeatedly.

The drawings of the UNl/163, with the dippings and instructions, were passed to Avenue House production unit.

After the first UNl/l63 units were manufactured I was told that the cost of a unit was excessive due to the breakages when 'Milling Off' the excess moulding compound from the ferrite assembly.  My enquiry as to why they were requiring machining was that the encapsulation was rough because the dippings were not being used.  The reason given was that the Foreman was embarrassed to give the dippings to his female staff for use in encapsulating the assembly!

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