[Amps] 813's

[Gudguyham at aol.com]

In a message dated 5/27/2006 5:17:52 P.M. Eastern Standard Time,  
chris at g3vbl.co.uk writes:


The  ARRL publication "Single Sideband for the Radio Amateur" Fifth 
Edition  1970 also has these amps on pp138-141.



I too have seen these amp articles and indeed the tubes were mounted  
horizontally by the author whom I do not remember his name. Assuming Collins did  in 
fact make a transmitter with 813's in the horizontal, I would think it is OK  
to do so.  I do not know what tubes their "service manual" called for but I  
think RCA tubes were used by the military which I think also carried a VT type  
designation.   Now there may have been a "mil spec" type of 813 which  
allowed this type of mounting but I really doubt it.  I would think that  the mil 
spec would have dealt with other issues in regard to the tube.  I  would think 
that a tube would have to be somewhat "ruggedised" to be used in a  military 
setting.
 
On the other hand I am not aware how the Collins transmitter was set up in  
relation to vertical vs horizontal if you know what I mean.  Does anybody  
know?  Sometimes units are built as modules  and then orientated   differently in 
the final unit which may change the orientation.   If that indeed is not the 
fact with the Collins, I would assume it is OK to run  them horizontally. 
 
 So I guess the final issue would be to know if the  orientation in the 
Collins military radio was in fact horizontal and  if there was a "special" version 
of this tube for military purposes to deal with  this fact?  Does anybody 
know this? 
 
 I once had a set of NOS military issued 813's in their original  packing and 
if I recall there were some markings on the tube (looked like an  anchor of 
sorts) which might have signified "NAVY"  73 Louie  W1QJ