Anybody looked at tube perveance values?

[Old Tele man]

One famous book, Radiotron Designers Handbook, 4th Ed., 1952, by F. Langford-Smith, uses G for Perveance (page 2 bottom):

http://frank.yueksel.org/other/RCA/R...cteristics.pdf

Another is Spangenberg's book, Vacuum Tubes, 1948, pages 202-203 (triode) and 239 (tetrode):

https://ia801803.us.archive.org/34/i...s%20(1948).pdf