> Why not use triode/or supercathode connected 8122s or 8072s instead of the
> 8875s? Same socket. Cheap price and you can still get abt 50 of the 8072s
> in Scandinavia. The G1 can take 100 mA and the G2 using the same cup
> construction should be able to handle even more current as it has a
> thermal connection with the outside world and larger diameter.
You have to watch some of the "supercathode" configurations.
Some destabilize the PA, especially near the operating frequency
on the higher bands.
The capacitor divider scheme only works properly when the tube is
in a class 1 service, with no grid current. An inductive tap,
assuming the the inductor is an autotransformer with high mutual
coupling and low ESR, works OK if the tube has a bit of grid
current.
The screen or screen and suppressor or beam forming element
should always be at RF ground, so don't use the system that
elevates the screen or suppressor elements for RF.
> Can anybody familiar with those tube curves look into the 8122/8072 curves
> if they are linear enough run in my suggested application?
Usually triode connection curves are not available for tetrodes. I
have no idea how that tube would behave.
73, Tom W8JI
w8ji@contesting.com
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