Radio Society of Great Britain RSGB callsign G3PTH membership badge

A scarce original circa 1950's 'Radio Society of Great Britain lapel badge', small gilt diamond shape example, inlaid with black enamal, depicting a radio mast, with additional ribbon scroll below bearing the callsign 'G3PTH', the reverse impressed 'Maker G5LJ'. Very good condition, complete with original lapel fitting, no damage to the enamel. Height 28mm.