What's the radio scale bar for?

April 6, 2008 7:33 AM

A number of radios I've owned in my life, in addition to the AM and FM frequency labels, also have a "Scale" label, going from 1 to 10, across the range of frequencies. What's this all about? Is it ever used for anything? I've never heard a radio station say "Tune to 6 on your Scale Bar".
posted by Jimbob to Technology (6 answers total)

Its a long time since I've had a radio... at all, but if I'm thinking of the same thing you are, I think its used for fine tuning.
posted by missmagenta at 7:52 AM on April 6, 2008

It helps to determine how near either end of the spectrum you are.
posted by netbros at 7:57 AM on April 6, 2008

Best answer: In my SWL days I'd sometimes use the scale bar for a more precise location for the station I had been listening to. Frequency numbers on a basic radio are not very precise. E.g., a station might be somewhere between 107 and 109 on the FM dial, but precisely 8.9 on the scale bar. I'll be watching this thread for other ideas.
posted by JimN2TAW at 10:15 AM on April 6, 2008 [1 favorite]

I've always assumed it was marketing BS. More scales means the thing is More Powerful!
posted by gjc at 3:29 PM on April 6, 2008

JimN2TAW has it. They are on all of my old antique, tube-based, multi-band radios. (Some old broadcast radios had many shortwave bands on them... I have one with 5.) Purely a memory aid and convenience thing for ancients who did not feel comfortable with terms like "megacycles".
posted by FauxScot at 6:51 PM on April 6, 2008

It's usually called the "Log Scale" as in "keep a log" (not logarithmic).
Mechanical tuning scales are non-linear so these really were helpful as JinN2TAW said.
posted by Fins at 10:14 PM on April 6, 2008