Ron-
I have a couple of Radios No.16 lamps- I can measure tomorrow.
In the mean time, here are pictures of one that I polished up and sent to Velo-Lumino to be retrofit with modern LED internals. Pictures by Velo-Lumino.
https://www.flickr.com/photos/hudson...h/31822285082/
Robert Hudson
Petaluma, California