[Boatanchors] Glob Champion

[Glen Zook]

The AX-9909 tubes used in the Globe Champion 300, 300A, 350, and 350A can be replaced, with 5894 tubes, with a fairly simple modification.  The 5894 uses the same tube socket as the AX-9909.  However, the plate connection is made to the top of the tube instead of from the tube base.  The 5894 is actually a twin tetrode and the plates and grids have to be wired in parallel instead of the single connection in the AX-9909.

I made this conversion in my WRL Globe Champion 350A and the power output, at the same power input, is about 10, to 15, watts more than with the AX-9909.  This may be due to the fact that the 5894 was designed for VHF / UHF use and, at HF, the tube may be more efficient.

Since the 5894 was used extensively by companies like Motorola and General Electric in their commercial FM two-way equipment, they are plentiful and relatively cheap whereas the AX-9909 are, generally, pretty expensive.
 
Glen, K9STH


Website:  http://k9sth.com



On Tuesday, December 24, 2013 7:04 PM, john <johnmb at nc.rr.com> wrote:
 
That is a pretty looking rig, barring a few wayward knobs.  They are not 
common, that's for sure.  Tubes shouldn't be a problem with the Amperex 
final modification.

Shipping however.....

Merry Christmas
John K5MO

III 


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