In this video I grab these two ancient bits of aviation technology from the 1940’s. They are vacuum tube radios specifically designed for aviation use as navigation aids.
You’d dial in the frequency of the airport you were trying to find and listen for the repeating Morse code signal. If it was getting stronger, you knew you were heading in the right direction. Conversely, if it faded or went away, well…. you weren’t.
The Learadio is a neat little item, but I cannot find much information out there about it. It’s like it doesn’t exist. No schematics, advertisements, nothing. It can run off AC power, and pick up standard AM radio which is a bonus. I guess when you got where you were going you could listen to the news or the ball game or whatever. If you have a line on a set of schematics or really any information at all except what’s already available on antique radio museum I’d love to see it.
The Motorola is a little more accessible, but since 1) its only battery powered, requiring a B-cell which I don’t have, and 2) its only for the the long wave signals, and 3) doesn’t have a speaker and I don’t have the required high-impedance headphones needed…. I just crack it open and take a look.
There are still some of these NDB stations transmitting out there. If you have a shortwave radio that will tune below the AM broadcast band and a decent antenna you can likely pick up one or two late at night.
Just another weird little corner of my collection that really serves no useful purpose other than to be interesting to look at, and interesting as a historical footnote.