Radio Reception On Motorcycles Using Class-D Amps - Installation Advisory – Rockford Fosgate

After installing a Class-D (Class-AD) amplifier on my motorcycle, I loose AM/FM radio reception.
The amplifier is mounted on top of the radio. What could be the problem?

Installation Advisory
Reduced AM/FM Radio Reception In Motorcycle Installs Using Class-D and Class-A/D Amps

ISSUE:
Class-D and Class-A/D amplifiers have power supplies that switch on and off at high frequencies, which can emit EMI (Electro-Magnetic Interference) signals into the air. These signals can cause interference with signal processors, wireless devices, and radio waves including AM and FM signals. Modifications in amp designs have been made to keep this to a minimum. However, devices that are in close proximity to the amp can still suffer from such interference.

SOLUTION:
1. Mount the amplifier as far away as possible from the motorcyle’s radio, antenna and antenna cable.

NOTE: Antenna placement seems to be key. Bikes with a rear whip antenna seem to be O.K. Fairing mounted aftermarket antennas do not work when amplifier is mounted to radio.

2. Keep amplifier cables - which carry interfering signals - away from radio, antenna, and antenna cable.

3. Provide a good amplifier ground. Ground cable should run directly to battery. Grounding an amp to motorcycle fairings or forks is insufficient due to higher current requirements of amplifier.

4. Aftermarket tuners are more susceptible than factory tuners to noise issues. Amps mounted close to aftermarket radios have more interference than amps mounted to factory Harley-Davidson radios.

5. Some stations might get skipped by the SCAN function, but if manually tuned, will come in fine.

2014 & NEWER MODELS ONLY:
2014 factory Harley-Davidson radios have a “Cat Scan” - if not set up right - will not allow tuner scan to stop on all channels. A software reset may unselect previously chosen AM/FM search categories. To resolve, enter “Cat” menu and check each genre to include when scanning radio stations.

• Download Product Advisory PDF

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