Anyone notice today's export radios with FM are more susceptible to adjacent channel interference on AM than an older radio like a Cobra 148GTL? If you don't care about FM or wire in some sort of switching, there is a way to improve that. Most radios with FM, only have one 455Khz. ceramic filter in their IF strip. In order to work with both AM and FM, a lousy compromise had to be made. FM on this band is plus or minus 5Khz. maximum deviation and the right filter for that would be 10Khz. wide. AM is about 6Khz. wide and these radios use a filter that is 8Khz. wide. Too wide for AM and too narrow for FM.
Get a Murata 455 filter out of an old 8719 Uniden board to use it for AM in these radios and notice the improvement. It's not just less bleedover and heterodynes. It also improves the signal to noise ratio by reducing the high frequency content in any white noise and interference.
Get a Murata 455 filter out of an old 8719 Uniden board to use it for AM in these radios and notice the improvement. It's not just less bleedover and heterodynes. It also improves the signal to noise ratio by reducing the high frequency content in any white noise and interference.
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