[OT] Locating source of FM radio interference

[Michael ODonnell]

Something near our house has recently started
generating spectacular amounts of radio intereference
that's most noticeable around 89MHz.  I have no
portable radio equipment of any kind except a humble
little $10 handheld with a normal telescoping antenna
that seems not to be very directional, or at least I
don't understand its directionality.  Is there some
way I can use it to do some sort of triangulation on
the source of interference?  Maybe some particular
way of holding/orienting it, or selectively/partially
shielding it, or tuning it, or...  ?