Here is Robert Bazian's (editingrus@yahoo.com) amazing radio. It uses only one transistor for gain but manages to pick up several stations clearly with no external antenna and it drives a speaker, too! You don't have to put your ear up to the speaker, either; there is plenty of volume. His receiver uses a ferrite loopstick antenna and a specially constructed RF transformer and it could be described as a "regenerative reflex receiver". It amplifies the RF with regeneration, detects the RF with a diode, and then uses the same transistor to amplify the audio. And, it manages to stay very well-behaved over tuning and volume settings.
Note the special RF transformer to the left of the speaker and the long loopstick antenna. His secondary winding on the loopstick is located some distance from the main coil giving him great selectivity and a full tuning range. The large speaker gives excellent sound.
Here is his schematic:
Now that is pretty simple!
Robert does it again with this nicely-working radio that uses two, 6E2 magic eye tubes...only! Check out the video.
