I'm fixing up some older ham transmitters. 811 or 6146 finals, etc. in
the 50-200 watt class.

Invariably these have sat on the shelf for so long because the RF choke
for the final died a horrible death (sometimes charred beyond
recognition) in their final use. I myself have fried/burnt several RF
chokes and other final components in Heathkits etc. but that was many
years ago when I could order exact spare parts. Sometimes a capacitor
or two is burnt up too, but these I already have in the junkbox or can
buy off-the-shelf.

The chokes that burned up seem to be between 1mH and 2.5mH or so, and
were lattice-wound on what seems to be a ceramic form. Maybe it's a
ferrite, but I don't think so.

6146/811/sweep tube handbook construction articles from the 50's show
similar RF chokes in their circuits and part numbers like "National
R-100" and "Ohmite Z-214".

I look in modern catalogs and I see molded (almost certainly ferrite
core) RF chokes in the right inductance (low mH) and current (100mA to
a few hundred mA) range but they look nothing like the old
lattice-wound choke. Are these suitable substitutes for the originals?
Something in the back of my head says that ferrite core losses with
all that RF across the choke will make the thing burn up at transmitter
RF power levels even if I'm below the DC current limit for these parts.

AES lists some pi-wound 1mH and 2.5mH RF chokes (ferrite core) that
look more like the original. Better idea for these?

If I wanted to learn to rewind the original chokes (very often they
double as ceramic supports for the anti-parasitic RL network and plate
caps) are there any web resources that would tell me how to wind my own
lattice-wound RF chokes? I've wound my share of simple solenoidal
coils in repair/homebrew endeavors, but the slices in these RF chokes
seem very ornately wound. I think there's a Lindsay or similar book
about coil winding, is that on my "gotta own" list?

Oh well, back to replacing those smoking electrolytics in the power
supply, I know how to do that!

Tim.