Dan Jacobson wrote:
"A Yagi doesn`t help, as we are depending fully on the null."

Dan also wrote:
"I am the owner of great sheets of metal."

If "your favorite FM station, 90 Mhz," differs in direction from its
interfering "competition, and only with a horizontal dipole at a certain
azimuth", a Yagi made by adding a director and a reflector should
increase signal to noise ratio.

Great sheets of metal can be used as a corner reflector for a favored
dipole. A 90-degree reflector can give about 10 dBd gain. A 60-degree
reflector can give about 2 dB more gain than the 90-degree reflector.

J.D. Kraus documented the corner reflector, Proc. I.R.E., 28, 513-619,
November 1940. Consult Kraus, "Antennas" for complete information, 1950
edition, page 328.

Best regards, Richard Harrison, KB5WZI