Description
What are those two ''tin cans'' on top of the 1947 AWA 500MY radio chassis ?
Well.....it's quite simple really.....under each of those two aluminium ''cans'' is an IF (Intermediate Frequency) transformer consisting of a primary and a secondary coil.
The primary coil is tuned from the TOP of the can, and the secondary coil is tuned from the bottom of the can (under the chassis).
Watch the video closely to see how the IF transformers are tuned using a ferrite slug which varies the INDUCTANCE of each coil by moving the slug up or down.
t should be noted that this receiver does NOT employ a separate RF amplifier stage, and as a consequence, the sensitivity on reception is only in the vicinity of 10 to 50 μV. As a comparison, a well designed communications receiver of that era had a much improved sensitivity of around 1 to 5 μV. (microvolts) due to the addition of a separate Radio Frequency Amplifier stage.
If you're located a long distance from the transmitter(s), the poor sensitivity of this receiver will result in ''background noise'' when you attempt to tune in the station....or...you may not even be able to hear the station !
You can see the underside of the chassis here https://www.youtube.com/watch?v=Sz7P0Zb0Z4g