Except that it isn't actually a radio but an oscillator that you could use to build a radio (by mixing the output of the oscillator with some input signal that you want to demodulate, and then to use the LF output of the mixer, aka the difference frequency).
But the article doesn't do that, and then goes off to show how you can turn this oscillator into a primitive (unmodulated, so only a carrier wave) transmitter.
(fun thing to do: wind that coil from thinner wire and demonstrate the microphony effect by talking to the coil, or glueing a plastic toothpick to it and a membrane to make it more sensitive).
If you really want to build a single transistor radio:
It is a radio and has FM modulation. Doesn't need complicated mixing for FM if you can skew the osc resonant frequency quickly I.e you don't need an IF system. In this case the transducer does that.
Its not CW, as that is switching the osc on and off.
This is as basic as it gets however. Noisy, full of harmonics but nevertheless cool. I've seen stuff not much more complicated than this doing some impressive distance.
"So now you should in theory have a working FM transmitter. How do you test it? Well you could build an FM receiver, which would almost be identical, just in reverse. However, I believe this would be an excellent opportunity to demonstrate the utility of SDR. With a $20 USB dongle from Amazon and the following tutorial, you can operate your own SDR receiver from your computer."
So no, it's not a radio. The radio is in the dongle, the other part is just an oscillator. So it's more likely about 1/2 million transistor radio or thereabouts (estimate of the # of transistors on the chips in that dongle).
The 'crude mixer / demodulator' can be done with just one transistor, this just isn't that.
It is a radio transmitter (and therefore a radio) regardless of what the TFA says. If you drag our your field strength meter or scanner and tune it to around that band, you're going to get a signal. Probably not a very strong one but it's still there. The big chunk of wire hanging off it is clearly an aerial so it even shows intent of being a radio.
Seeing as it's 49MHz, it'll even show up on analogue baby monitors etc.
But the article doesn't do that, and then goes off to show how you can turn this oscillator into a primitive (unmodulated, so only a carrier wave) transmitter.
(fun thing to do: wind that coil from thinner wire and demonstrate the microphony effect by talking to the coil, or glueing a plastic toothpick to it and a membrane to make it more sensitive).
If you really want to build a single transistor radio:
https://www.google.com/search?client=ubuntu&channel=fs&q=sin...
Shows plenty of results, one of which is the article linked here.