[Amps] Plate Choke Query

[Jim Garland]

            I'm making a plate choke for a duoband 80m-160m amplifier and
want to solicit any comments. The tank compartment is space-limited, and at
most I can have 4 inches of winding length on a 1 inch diameter form.
Ideally, I'd like to have even a shorter winding length and smaller diameter
form. I'm thinking 150-200 uH would be satisfactory, but if 100 uH would
work, that would be better. Four inches of close-wound 24 AWG wire on a 1
inch diameter form should give about 200 uH. I'll be using either a teflon
or delrin rod for the choke. I don't have experience with delrin, but I like
the fact that it's not as slippery as teflon (and hence easier to stabilize
the coil winding). I've heard delrin has good RF properties, but don't know
that for a fact. (I know nylon can't be used.)  

            The plate impedance of the amplifier is about 700-750 ohms, and
200uH is about 2.2K reactance on 160m. I have no idea about the Q of the
choke, but it will probably be 100 or a bit more. I'll bypass the cold end
of the choke with several 1000pF caps. Since the choke is only for use on
80m-160m, I don't think self-resonances will be a problem. Any comments or
suggestions?

Thanks!

Jim Garland W8ZR