Brad wrote:
"I want to build a fat dipole for FM listening for my brother-in-law,
who refuses to get a rotor."

A twin-lead dipole may be fat enough. These are sold at Radio Shack and
other outlets for just a few dollars and can be used to determine if
such an approach is satisfactory. You can still build an "improved
antenna" if the bought antenna works on site.

Best regards, Richard Harrison, KB5WZI