@ All
This is being posted as I found it on http://people.clarkson.edu/~ekatz/scientists/meissner.html
Not sure if this is the answer to other OU avenues but it sure looks interesting for a REALLY OLD TRIODE !
"Alexander Meissner was born on September 14, 1883, in Vienna, Austria. He studied at the Vienna College of Engineering, earning the doctor of technical science degree in 1902. In 1907 he joined the Telefunken Company of Berlin, where he conducted research on radio problems. He improved the design of antennas for transmitting at long wavelengths, devised new vacuum-tube circuits and amplification systems, and developed the heterodyne principle for radio reception. In 1911 Meissner designed the first rotary radio beacon to aid in the navigation of the Zeppelin airships.
In 1913 he was the first to amplify high-frequency radio signals by using a regenerative (positive) feedback in a vacuum triode; this principle made it possible to build radio receivers more sensitive than any earlier type. In June 1913 Meissner used this electronic circuit to transmit speech."
Regards,
Paul