"James" wrote in message
. ..
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


You can start bu scaling the antenna length . That is devide 146 by 156
and get around .94. Then multiply the length of the element by .94.
As pointed out the loading (matching) coil will probalby need to be modified
somewhat for a perfect match, but this should get you close.