The XLF-20C? & XLF-20M? look exactly like the original PLF-10C? & PLF-10M?, the differences are in the electrical circuits.
All noise or interference enters a 2-way radio thru the antenna system or the 12 volt DC lines.
The XLF-20C? & XLF-20M? are rated at: 6-16 Volts DC "20" amps continuously, and are known as "COMMONMODE" filters. Unlike the PLF the XLF's address a WIDER range of interference problems and will reduce or eliminate not only DC noisewhich include alternator, turn signals and windshield wipers, it will also cancel any RFI that is coupled into the DC line, and due to it's design there is absolutly no voltage drop thru the filter. In addition the commonmode filter provides the highest isolation to both RF and Noise.
Commonmode filters will reduce or eliminate noises in all 12 volt electronic components, these include 2 way radios, audio systems, including AM/FM receivers, stereos, amplifiers and video components.
The instructions on the backer card now give instructions for a simple test that will determine if the noise/interference is thru the Antenna or DC lines.
All noise or interference comes into your radio either through the antenna system or the DC power lines. The XLF-20C? and XLF-20M? will effectively cancel or reduce the noise coming through the DC power lines. To determine if the noise you are experiencing is coming in through the antenna or DC power line, conduct this simple test:
1. Start the vehicle and listen carefully to your radio's receiver noting all interference and noises. Start and stop the various DC switches and motors in the vehicle (windshield, wipers, turn signals, etc.)
2. Unscrew the antenna from the back of the radio and replace it with a dummy load.
3. Repeat step #1 and compare noise levels.
4. Any noise or interference that remains after the antenna system has been replaced with a dummy load, will be reduced or eliminated by using the XLF-20C? or XLF-20M?.