amdx Inscribed thus:

I have an FM radio inside an aluminum boat. The radio worked ok with
the AC cord as the antenna but I got interference when I used my
laptop. I found the circuit that ran from the power transformer to the
antenna input on the
FM IC. I installed a connector that is used on car radios and wired
the center pin
to the foil that went to the FM IC (capacitor on pcb isolated) and the
shield side to
dc ground near the IC. I then plugged in a telescoping car antenna and
it worked
great on the bench .
So I installed the antenna on the outside of the boat and the radio
inside, now one station I listen to is weak, but if I unplug the
antenna and let the center pin touch ground of the connector on the
radio it comes in great. Just curious why it is working this way.
BTW, the mod did cure the computer hash.
Mike

Sounds as if the antenna is fed with co-ax and has too much capacitance
across the input. Put a trimmer capacitor in series with the centre
pin and see if that improves things. Try 2-20 or 5-50pf.

--
Best Regards:
Baron.