- battery chargers
- blower fans
- DC-to-AC inverters
- depth sounders
- electric fuel pumps
- engine alternators
- engine ignition systems
- engine starter motors
- engine tachometers
- fans
- fluorescent lights
- high-amperage wire runs (e.g., power
feeds to bow thrusters, anchor windlasses,
and electric winches) - lighting transformers
- radars
testing for electromagnetic and radio frequency interference 89
- shore-power isolation transformers
- trim tab motors
That’s a fairly long list of culprits. And
what are the common victims of EMI/RFI?- AM/FM stereos
- audio systems
- autopilot direction sensors (fluxgate
sensors) - computerized engine controls and their
wiring harnesses - flat-screen TV monitors
- depth sounder transducer cabling
- DGPS receivers
- Loran-C receivers
- magnetic compasses
Interference is caused by unwanted radio frequency energy. The energy is picked up by antenna systems and wiring cir-
cuits and fed to receivers, which may not be able to distinguish between noise and signals if they share similar frequen-
cies. (Reprinted with permission from Boatowner’s Mechanical and Electrical Manual,third edition, by Nigel Calder)