https://antiqueradio.org/radiola3.htm
The Radola 3 is the craziest circuit that I have ever seen. One coil rotates 90 degrees within another. It has no tuning capacitors or electrolytic capacitors. My working Radiola 17 doesn't have any any electrolytic capacitors just iron core chokes. I added an electrolytic to the power supply reduce hum. The 17 plugs in and has tuning capacitors, quite and advancement in just for 2 years 1924 to 1926. The 17 has no AGC the volume goes up and down as you approach it. Within a few more years superhetodynes came out with AGC, tuning capacitors, and electrolytic capacitors. I wish cold fusion was moving that fast. It is interesting to work with these nascent technologies. It is quite odd to realize that most modern homes do not even have a stand alone radio today, What would they have predicted about this in 1924? Frank
