Dave, as stated in my OP, this is a 5/8 wave antenna. It is the antenna
that I have bought and that I will use temporarily. This will be for a very
temporary use, and I agree with your suggestion about a marine 1/2 wave,
which I will do later on.

My question is "about" how much to trim for 156 mhz use. I will use an
SWR meter to get it right on spot, but I would like a feel for how much to
trim. It is tricky to calculate , even using the "468" formula,
because of it being base-loaded.

73 de Jim K4PYT