Just a wild guess....
There is enough pickup die to leads to hear the station at the input of the 45mhz mixer and?
its second harmonic 90mhz plus DBMs make very good phase detectors (that means
they also can detect frequency changes).? I'd bet you are not far from the station.
IF the input low pass filter is right this should not happen but if you have wire loops?
you can get around the back of the filter.? Shielding is your friend.
FYI I grew up in the shadow of a AM BC station and everything I did picked it up
even ma bells telephones!
Allison
