Hi Bill and Co...
:From: Bill Aycock <baycock@HIWAAY.NET>
:..I have acquired parts of a commercial mobile tube rig
:.. The final is marked "Amperex", and is numbered 5894B
The 5894 and similar numbered tube were very common
in the Two-Way Communications Radios through the 60's
and early 70's. The good old Motorola Research Line
("Motrac - Sensicon Series"), RCA ("Really Crappy Audio")
Radio Carphone and the General Electric Master Progress
Line ("Master Pro")used them as finals for most of their
VHF Hi-Band Radios. In both mobile and fixed applications.
The 5894 is considered a big brother or upgraded version
of the 829b tube and they use similar sockets. The 5894 is
almost a third larger and has "upgraded ratings." There
was and article in a past Amateur Publication where
someone mounted a transmitter strip in a box with fixed
power supply, using only the separated final section.
I have a copy of it in my files somewhere.
Here's the meat and potatoes...
I've converted a number of these old strips down to the 2
meter band. You will have to add capacitance to the final
section, it's very dependant on the "band-split" (section of
the VHF band where the strip was built for operation by
the mfgr), how much additional work you'll have to do. I've
even hack-saw'd off the final section to make smaller box
amplifiers.
5894 at "full tilt" will put out 90 watts plus, but you'll burn it
up quickly with long key downs. I used the FM IMTS
Telephone continuos duty values and obtained 35-45 watts
all day, every day for many years in my GE EP-38 chassis
Master Pro FM Repeaters. Prudent operation has a fan
blowing air past the tube in operation. The VHF Master
Pro transmitter strip actually mounted the tube in a Heat
Sink final assembly. The Motorhead version was air cooled...
Older Handbooks and the FM and Repeater for the Radio
Amateur contain amplifier circuits using this tube and the
829b. I even have an 829b amplifier in the back room.
What a whooping 35 watts on 2 meters...
cheers
skipp
http://sonic.ucdavis.edu
http://pilot.ucdavis.edu
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