This is a fairly common issue with "common mode" RF interference from the CB radio's transmission entering into the intercom.
Often the "fix" can be as simple as routing the antenna cables as far away from the other system cables as possible and verifying that the antenna's ground is perfect.
Honda ran into this same trouble in 2006 with the Airbag models and created a service bulletin ( http://www.goldwingfacts.com/1800%20Service%20Bulletins/1800SB19.pdf ), which also introduced the addition of ferrite core-chokes in pigtails (small extension cables) for the intercom system .. these pigtails help to remove the RF from the audio signal.
I don't enjoy paying Honda's price for these cable bits,and simply added some cinexpensive ferrite beads onto the existing harnesses to achieve the same effect.
I'm certain that something similar would be available to you locally, as this type of signal interference is quite common in AM transmitter operation.
I believe that this squeal is the driving force behind why the OEM CB radios all seem to be set for such pathetically low levels of modulation, which so greatly reduces their usable range.
Often the "fix" can be as simple as routing the antenna cables as far away from the other system cables as possible and verifying that the antenna's ground is perfect.
Honda ran into this same trouble in 2006 with the Airbag models and created a service bulletin ( http://www.goldwingfacts.com/1800%20Service%20Bulletins/1800SB19.pdf ), which also introduced the addition of ferrite core-chokes in pigtails (small extension cables) for the intercom system .. these pigtails help to remove the RF from the audio signal.
I don't enjoy paying Honda's price for these cable bits,and simply added some cinexpensive ferrite beads onto the existing harnesses to achieve the same effect.
- To decouple any RF from the outside of the CB antenna cable, I added a snap-on ferrite bead near both ends of the CB cable.
- To protect the intercom amps and inputs, I fitted some smaller beads onto bike's harness just inside of the headset connectors and again another bead to the 5-pin DIN connection.
I'm certain that something similar would be available to you locally, as this type of signal interference is quite common in AM transmitter operation.
I believe that this squeal is the driving force behind why the OEM CB radios all seem to be set for such pathetically low levels of modulation, which so greatly reduces their usable range.
