I believe this D.C. Milliamperes meter could have been used in an early war bomber radio set up? It’s dated 1938, manufactured by Edward Turner, with the A.M. Crown and the ref number 10A / 3458, model 444. Does anyone recognise this, and know what it was fitted to?
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By: jamesinnewcastl - 21st April 2013 at 17:37
Interesting that it is a linear moving coil ammeter and only marked up to 100mA, moving coil meters are DC – the ones I’ve seen on the 1154 and 1155 set-ups are usually ‘Hot Wire’ types used to measure RF current in a direct manner and usually much higher current, in fact 4A is shown in the previous drawing. Being ‘hot-wire’ they had non-linear scaling (again see previous drawing).
It is in exactly the same sort of case as the 1154 and 1155 with an in-circuit and out of circuit type switch (i.e. don’t waste precious antenna power showing me the antenna current!)
It’s possible to have a linear meter for the purpose but with different internal circuitry, this one seems to be an exception to the general rule – worth looking into more perhaps, rarer, later?
Cheers
James
By: Peter - 21st April 2013 at 15:16
Here is a schematic showing that part in a lancaster.
By: anneorac - 21st April 2013 at 10:38
It was part of the T1154/R1155 set up so was found on a host of aircraft (and boats) from about 1941.
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April 21, 2013 at 7:53 am