[AMRadio] RE: SWL'ers and AM (Also Philco and RCA too!

[Donald Chester]

So, was the purpose of Locktal tubes to get around the RCA copyright, or to 
prevent the tubes in automobile radios from working out of their sockets 
from the vibration?

It has been my experience with locktal tubes in house radios that the 
sockets become noisy and intermittent.  However, the physical construction 
of the tubes is very similar to that of miniature tubes.  I suspect the 
concept of miniature tubes borrowed heavily from locktals.

Don K4KYV