There's some disagreement over it, but it does seem likely that Lilienfeld built a working radio with his FETs. We know he drew a schematic of one and it's spec

There's some disagreement over it, but it does seem likely that Lilienfeld built a working radio with his FETs. We know he drew a schematic of one and it's specific enough that it seems likely it was the result of practical experimentation. Here's one quote: In 1981 the semiconductor physicist H. E. Stockman said "Lilienfeld demonstrated his remarkable tubeless radio receiver on many occasions, but God help a fellow who at that time threatened the reign of the tube."