I made an Eico FM radio kit about 52 years ago. It used vacuum tubes and was very sensitive, had good selectivity for all the FM radio stations around me and had low distortion. When FM stereo was invented a year later then I made a stereo multiplex adapter kit for the radio that also worked well.
About 50 years ago I used a tunnel diode in an FM transmitter then I used it in a regen FM radio. The regen radio worked very poorly.
About 50 years ago I used a tunnel diode in an FM transmitter then I used it in a regen FM radio. The regen radio worked very poorly.