| Here's the story of one AM tube radio's journey to FM |
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Back in the late 50s, most stations broadcasted on AM only. FM did not become prevalent in broadcasting until well into the 70s. True, FM was first demonstrated in 1936. Armstrong broadcasted via FM as early as the 40s. By the end of the 70s, approximately half the listeners in the US were listening to FM stations.
Vacuum tube radios were primarily AM only receivers through the 60s. There were some manufacturers throughout this period which made FM and dual AM and FM receivers but it was less common. |
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FM is a different electronic design than AM. While the amplification stage is pretty much the same, FM demodulates incoming signals by frequency while AM demodulates by amplitude. The electronic circuit design to perform one versus the other is different.
In other words, you cannot modify an AM radio to receive FM by just swapping out a few parts. You need to re-engineer the electronic circuit. It would be more time consuming to do this than it would be to replace the chassis altogether. Replacing the chassis has its downsides associated with it, and not just all about the electronics.
Like, where will you mount the switch to go from AM to FM? Are you going to drill a hole in front? Where are you going to find a matching knob?
What about the tuning dial? Are you going to re-print the scale so it has AM and FM frequency readouts? How's that going to look... |
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| | Here’s a table top radio that looks like a portable. Rare model and color combination. The metal back serves as an antenna for this radio. How clever! Manufactured by Motorola in 1959 is in excellent working and physical condition. Picks up AM stations clearly and loudly up and down the dial without need of external antenna attachment. | | |
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| | Cool mid-century deco styling on this vintage radio. The entire top, sides and back are rounded like an old 40s Greyhound bus. Tabletop tube AM radio manufactured by RCA Victor in 1940's excellent working and physical condition. Cabinet is original factory glossy brown bakelite. | | |
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| | Tabletop tube AM radio manufactured by Silvertone in late 1950's excellent working condition. This radio is the epitome of mid century modern styling! Rare and beautiful! This model features perfect combination of styling, colors and textures to epitomize late fifties. Absolutely stunning to behold. | | |
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