[Kenwood] Need TS-520 history

[Mike Steussy]

Ahoy!  I'm writing up a little paper for my radio club on what I believe 
are the four most famous transceivers of the tube era.  One of these has 
to be the TS-520 (series).  I have information on the genesis of the 
other three (KWM-2, TR-4, HW-101), but am lacking info on the 520.  If 
you have information that might help me, please send or point me to the 
site.

Thanks & 73,
Mike Steussy AE4R
Vienna VA