[Kenwood] Kenwood TS-900

[Aidehua at aol.com]

I've gotten into collecting Kenwood stuff.  I recently picked up a  TS-900 
set that I like very much.  Wondering if there was more than one  version of 
this.  Some sources say there is a TS-900 "S" and then just the  TS-900.  
Wondering if this is true, and if so, what are the  differences?
 
73,
Ed NI6S