Rather a nice AVO "All wave Oscillator" circa 1952.
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This item utilises two L63 valves which are half of a 6SN7 and first introduced in 1938 as a direct copy of a 6J5 to achieve RF frequencies adjustable up through to the 10metre band. If CV1067s are fitted they are from post 1958 and if VR67, they were the Post Office type numbers from 1946.
A good view of the 400hZ modulation on the selected frequencies.
