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On Mon, 30 Jun 2008 08:08:28 -0700 (PDT), Connah
wrote: Perhaps the image of the first IF and the tx/rx split is the same? Hi, Brad! Thanks for your input. I must admit, I am ignorant of the subject of images though I have heard of this topic repeatedly. Would you mind explaining your thoughts in layman's terms or pointing me to a site where I could educate myself on this? I'm very interested in learning about. Thanks again, Brad! Have a good one. Matthew Every modern radio receiver uses intermediate frequencies in the demodulation process. This results in better quality signals being fed to the audio anplifier; thus, better quality sound from the loudspeaker. Usually the IF is given in the specs of the scanner, and by convention, 10.7 MHz is used in consumer radio sets. To get the image frequency of any given channel, double the IF and add and/or subtract the result to/from the given frequency. For example, my local NOAA frequency is 162.4 MHz. Image frequencies for it will be at 162.4 MHz. ± 21.4 MHz., or at 183.8 MHz. and 141.0 MHz. (2 X 10.7 MHz. = 21.4 MHz.) Tune your scanner to a given station's image frequency, and you may hear a signal strong enough to make you think that the station is operating on that channel; or stations operating on an image frequency may effectively jam reception of a desired frequency. Which as Brad points out, may be the case with your base/handset channel pair. Receivers which employ multiple intermediate frequencies aren't as susceptible to this issue. ~db~® |
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