If you have enough radials at or below ground you won't need a common
mode choke. You don't say if your inverted L will have an elevated
ground system or not. If the ground system consists of 60 or more
radials you can probably put a matching network out and the feedpoint
and forget about fooling around with common mode chokes and all that.
The RF current on the exterior of your feed line will be so small it
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