Radio noise

[rlricks]

The reception in my SL-40 is clear as a bell until I start the engine then it is almost unreadable. Any suggestions for a fix?

 

[Walt]

Find the noise source by turning off each item one at a time until you find the source, then fix the offending system.

 

[Bavafa]

Also check your mag wiring and make sure you have used shielded wire and that is grounded only on one end (mag side)

 

[Mich48041]

Make sure that the antenna base is well grounded. Disconnect the antenna, then start the engine. If the noise is gone, you will know that the noise was traveling through the air. If the noise is still there, then it is coming through the wires.
The magneto shield is grounded at both ends, however the shield is not continuous from end to end, being separated at the center conductor splice on the forward side of the firewall. Make sure that the shield is NOT spliced.
Check the voltage regulator to make sure it is well grounded (not mounted on a painted surface). And check the battery ground wire where it is attached to the airframe (no paint).
Let us know if you find the noise source.
Joe Gores

 

[Andy J]

Check the squelch setting on your intercom.

 

[mcattell]

Had similar issue. Do you have a Garmin portable GPS with audio wired to audio panel and powered from ship's power? If so unplug audio from Garmin and problem will go away. Will fill you in on fix if that's problem.