[BC] Bauer/Sparta 603/Paul Gregg response

[Mike Holderfield]

Hello Mike --

I saw your postings about the 603 - 605.  Your description is right on --  
particularly the reference to the ARRL
handbook. Work on the 603 started on the mid-sixties before Eimac had 
introduced the 5CX1500. Bauer
was located about a mile south of Eimac and a couple of Eimac engineers 
(both hams, of course) helped
in the design of that transmitter. This was before they had their own "black 
box" department. This series
of transmitters introduced the 5CX1500 -- followed shortly by the 602 -- the 
first 2500 watt transmitter.
We called the 3KW version the 603 and the 5KW version the 603A5 and it was 
built during the days when
Bauer was a part of Granger Associates and in the early 70's as part of 
Sparta. The 5KW version of the
transmitter found some interesting homes -- it was the first stereo signal 
in Rome broadcasting Jazz from
the Vatican. In about 1973 we turned to the 3CX3000 and subsequent models 
used that tube -- the 602,
however, continued up through the 80's until we closed the Sacramento plant. 
We had a good experience
with the 5CX1500 until Eimac ran into ceramic problems. Once they solved 
that -- and even introduced a
B version before they found the real problem it was OK until they changed 
the plating process which created
a socket  problem with the suppressor grid. The tube got a bad name during 
this period. There are still a lot
of 602's out there using either the A or B version of the tube. They tune 
differently but there charts in the
book to cover that.

The Bauer-Eimac connection also created the 1KW 607 using the 3-400Z and 
later the 3-500Z -- another
transmitter with the Ham look. Fritz Bauer worked with both Eimac and 
Electro Engineering (modulation
transformer and 12 pulse power supply) to develop the first high level plate 
modulated transmitter using the
4CX5000A (The FB-5000J).

Hope this info is useful to you -- I will send a copy to Barry.

Best regards,


Paul Gregg