Originally Posted by S/V Illusion
Fo receiving AM, you don't need coax. Run the longest wire you can as most AM broadcast is in the low end of the HF spectrum, i.e., long wavelength. Connecting it to anything attached to the boat's ground can create susceptability to lots of conducted noise
The reason I ran coax was to get away from the RFI of various digital goodies in the area of the radio
In urban areas, it wasn't a problem but when you're out in the islands, you need a lower noise floor.
Thus, the headstay, and no noise (at least on my boat).
Further, almost every AM/FM radio
I've ever repaired (in a previous life I did exactly that for 30 years) there's no DC coupling from the center lead of the coax to the chassis.
There is at least one capacitor before it goes to the first stage.
I did not connect the coax shield to anything at the headstay location, only at the radio's antenna plug