On 06 Mar 2007 05:40:40 GMT, Ed
wrote:

I wonder how to calculate or guess what it is at all.

Hi Ed,

The more practical consideration is: "What can you do about it?"

The loss is going to be in frame and chassis connections where the
loss is going to predominate. Another matter is getting over the idea
that what sticks up the air is the principle part of the antenna. You
may as well get used to the idea that it is only a tuned radial for
the bigger element, your RV. And what polarization is that RV going
to present to the world? (Probably horizontal.)

73's
Richard Clark, KB7QHC