Radios (and Transmitters)

May 28, 2019
 |  No Comments

The “barn radio” project is concluded (mostly).

The “barn radio” in its custom cabinet, playing happily…

Some sanding, some pre-staining, some staining, some varnishing…

The only missing (and vexing) element are the decals for the knobs. Ya know, “what does what?” The Philco from the prior year, which also needs some cabinet work, has very faded lettering under the knobs. Not sure I want to replicate that. But my usual routine, of using some sort of stick-on tape; that’s not gonna cut it either.

So. Mostly finished.

So what are we listening to on this radio, and all the others that have broken out around the house like a rash?

Well, the AM stations that come in in Rantoul by day are two: 580 KHz (“AM 580, WILL”) and 1460 KHz, WKJR, “Radio Variedades,” an Hispanic language station that swamps anything near it on the dial.

So my FCC Part 15 transmitters are filling the void. These are now five in total: two vacuum tube and three IC/transistor concoctions. I’ve written about one of them here. But then I built:

The Evan Armstrong 3 tube transmitter.
The PLL thing from the website here.
The Vectronics kit I picked up at the ‘Vention.
And … I bought one from Turkey. Had to sign for the package.

Package from Turkey!!!

So, here’s the report card:

The Armstrong schematic, which I built from scratch from his schematic, is a disappointment. It will only radiate a few feet. I’ve modded the output phase of the circuit and attempted to tune up an antenna on it, but it just won’t radiate. I’m an idiot, or I built it wrong.
The PLL thing just gets hot when 12 volts are applied, and doesn’t otherwise do a damn thing.
The Vectronics kit outperforms the the AES kit in every respect and is a total winner.
The one I bought from Turkey works, but I don’t know exactly how well. It does not seem to radiate as well as the Vectronics kit, and it has no antenna tuning facilities that I know of. I have not taken it apart; it was a finished product when delivered. 
There it is.