Reg Edwards wrote:

It may be of interest -

Doubling the length and diameter of a solenoid and reducing the number of
turns of thicker wire to maintain the same inductance, doubles the Q until
radiation loss resistance begins to predominate.

And it's a big coil for radiation resistance to predominate.
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Reg, G4FGQ

....and like i mentioned, put a (cylindrical) shield around it and you
still have a high Q and a lower frequency *due to the higher distributed
capacitance.
Alternately, use it as a slow wave structure in a (resonant)
cavity)...

(same difference)