[Boatanchors] Tube Id.

[telegrapher at att.net]

I'm thinking that the 6100 is a 6C4.  Is that right?  The other i'm 
curious about is a 6201.  It's the tube in the product detector of the 
51J-4 which according to another piece of information is a 12AU7.  Are 
these some of the FAA numbers?  I've got a shoe box full of tubes with 
similar numbers that did come from an FAA location.  Used so i don't 
know their status nor what they actually are so i can't test them. 
Maybe i'll make up a list and post it here to see what data i get back.

Thanks for help in advance.

Larry
W0OGH