Topband: Needed: Rule of Thumb

[Wayne Willenberg]

I have a 5' high chain link fence located  50' from where I would like to
put up an 80M vertical.  Obviously, I need to move the fence and
have plenty of room to move it. On the other hand, I want to minimize the
distance I move the fence due to the expense.

Is there a rule of thumb about how far away objects should be located to
prevent interference with the radiation pattern of a vertical?

Thanks for your help.

Wayne, KK6BT