Hi, I'm sorting through a pile of stuff from an SK estate and have found a box of 4 coils labelled "Coils No. 6 RFT, 19 to 30Mc RCA 253671-502, Box No. 1, Carton A". The coils are on what looks like perspex ribbed formers with adjustable slugs. Can anyone ID what these are for? I'm guessing they are from a spares kit. 73, Roger Basford, G3VKM