Unknown model, RK. According to the serial register for Radio (1936) Ltd they were 5 or 6-valve broadcast band sets made in 1946 to 'R. Lang Spec'
2/9/1946 - 5-valve broadcast bank model RK, serial 91703-91800 (98 sets) - No magic eye fitted
2/9/1946 - 5+-valve broadcast band model RK, serial 91801-91924 (124 sets) - Magic eye fitted
The two sighted examples have both been Golden Knight branded - it might have been a special order for them - and could have been simply a different dial glass from an existing model
General Construction Notes for Radio (1936) Ltd:
Early Radio Ltd. schematics did not show the models, just the year, valves and bands, so some sleuthing is required to find the right one.
Early 30's Ultimate models with three digit model numbers indicated both the number of valves in the set, and the price it retailed for - for example, the model 856 was an 8-valve radio which retailed for $56 pounds. The equivalent Courier models were reversed, so an Ultimate 856 was a Courier 568 (theoretically, at least). This was the Auckland price though, and often the sets would retail for 1 or 2 pounds more in other centres, presumably to cover the freight cost of moving them around the country from the Auckland factory.
Note the use of old resistance terminology on older schematics: ω means ohms and Ω means megohms.
Some 1936-onward 3-letter chassis codes vary the last letter between brands, for example:
BBU - Ultimate model BB
BBR - Rolls (and Golden Knight) model BB
BBC - Courier model BB
All use the same chassis.
Golden Knight, Courier and Rolls appear to use the same copper-painted chassis while Ultimate chassis' are painted silver
After the war a new model code system was introduced, whereby radio models all began with R - the first model being the RA, a dual-wave 5-valve set commonly released in a pressed tin cabinet.
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