Topband: matching an inverted-L

[k1my]

Hi Steve and all ....

Be gentle with me as I am not a "builder." Help me understand this. What is
a "largish air variable capacitor" and where do I get one? How much? What is
the capacitance range that I am looking for? How big does it need to be for
1.5KW on an inverted L? I assume that I put it in series with the L at the
bottom of the vertical leg. What do I then tune for? Minimum SWR at the
radio/amp? How broadbanded are these things? Or do I really need to change
the capacitance when moving within the 160 band?

Lastly, I have read that some people have tuned their towers with a coil? I
know that Hi Gain used to sell/spec a coil for the Hi Tower to use it on
160. What am I missing here? L or C or both? Or is an inverted L different
from a insulated vertical?

Again be gentle on me, I am not a techie.

73, Bruce K1MY