Description
The 1958 HMV radio model 64-52 seen here has four operational knobs, a great sound, and plenty of volume (enough to hear it clearly on the other side of the room).
All capacitors (except for four) have been replaced in this receiver, and after operating it every day for about two weeks there has been no sign of sudden noise such as ''silver mica breakdown'', so the four mica capacitors inside the IF transformer cans are obviously okay.
(Phil Coorey is the political editor for The Australian Financial Review, and also a commentator on Australian politics)
About the radio cabinets:-
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1950s Australian radios from a mid-tier or minor brand (such as HMV Little Nipper, Breville, Airzone, Tecnico, Kelvinator etc.) almost certainly had their cabinets contract-moulded behind the scenes by AWA, Philips (Hendon), Astor/RCA, STC, or an independent trade specialist like Nally, AMC, or Dunlop-Perdriau.
The internal ferrite rod antenna:
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This receiver uses an internal ferrite rod antenna.
When the ferrite rod is at right-angles to the AM transmitting tower, the ''figure of 8'' directional pattern exhibited by the ferrite rod, can, and usually does, reduce both interfering noise along the transmission path and local noise at the receiver site to zero, while at the same time, receiving maximum signal strength.
Radio waves are electromagnetic waves consisting of an electric field at right angles to a magnetic field....A ferrite rod antenna functions as a magnetic loop antenna that detects the MAGNETIC component of a radio wave, rather than its electric field.
This makes it highly efficient at picking up Medium-wave (MW) AM broadcast signals.
The ferrite rod concentrates the MAGNETIC lines of force through itself. This produces a much denser, stronger magnetic field inside the rod than could ever be achieved with a standard air-core rod.The fluctuating MAGNETIC field inside the rod induces a voltage into the antenna coil wrapped around the ferrite rod.
That coil forms part of the tuned circuit of the first stage converter tube which converts the desired radio signal into a lower fixed frequency called the Intermediate Frequency (usually 455 khz).`
When you move the radio for maximum signal and minimum noise, you are positioning the ferrite rod to be at right angles to the MAGNETIC component of the incoming radio signal (not the electric component).
That is WHY you must move the radio to get the best reception.
If you have an older tube radio with a 'long wire' antenna, you cannot tune out the noise like you can with a ferrite rod antenna, because the 'long wire' responds to both the electric and magnetic components of the signal, so moving the radio makes no difference !