[Fox_Tango] 6LB6's

[Dr. Gerald N. Johnson, electrical engineer]

My RCA tube manual has slipped away from the computer. At least trying
to find it I turned over a pile or two.

I don't have RF experience with these options. My last sweep tube rig
used a single 6KD6.

As WB9HNJ notes, the limits are plate dissipation and the terminal C,
especially input, output, and feedback (presuming the pin connections
are similar enough). Given choices, I'd prefer 6146(A or B) to any sweep
tubes because while the 6146 won't do the peak power, it also won't melt
on a long "AH". Sweep tubes tend to have a larger cathode and ham rigs
tend to run them to the limits of the cathode, not the plate, and also
have marginal linearity. One of the secrets of the clean signal from the
Collins S-line was RF feedback around the 6146 that are inherently far
more linear than any sweep tube. So going to 6146 cleans the bands a
little compared to over drive sweep tubes, and even more compared to the
modern sand state finals. The internal shielding against feedback is
present in the 6146, absent in the sweep tube.

73, Jerry, K0CQ

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