[Hallicrafters] 5894 Tube for the HA-6 Transverter

[David C. Hallam]

Is there anyone who knows about differences in the 5894 tube used in the
HA-6 6 meter transverter?  I picked up two tubes at a hamfest yesterday.
One is marked 5894A and the other has no identification.  I have tried all
the usual tricks to raise numbers with no success.  The unmarked tube
appears identical to the 5894A with two exceptions.

The anode surface has three radiating fins instead of two.
The anode connector pins on top are about 60% larger in diameter.

In other respects the tubes are the same; the glass envelope is the same and
the base pins are the same.

Is this tube just an improved version of the 5894A or what?

David
KC2JD/4