Hi Marty,
I, too, have an SB-221 which is still "cherry."
First, you'll have to take out a trap in the input circuit which will not
pass anything above about 25 mhZ.
A second problem is that there are not enough positions on the band switch,
but if you're willing to skip 15 meters, you can make out. If you really
watch for them, sometimes band switches can be found, or another with 5
positions can be subsituted.
The third problem is the input matching network and you'll have to start from
scratch on that. Also, you have to change the input band switch.
Fourth, you'll have to find or make a 10M inductor, though that should not be
a big problem.
All in all, it's just a big mess and you will pretty much ruin the re-sale
value of the amplifier. That's why I haven't dove (or diven? HI) into the
project.
If you do, please share your results with the rest of us trepidacious 221
owners.
73
Mike
WØYR/4
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