Radio Shack PRO-76 - Manual (Page 33)

33
AVOIDING IMAGE FREQUENCIES
You might discover one of your regular stations on another fre-
quency that is not listed. It might be what is known as an image
frequency. For example, you might find a service that regularly
uses a frequency of 431.875 also on 474.675.
To see if it is an image, do a little math.
Note the new frequency 474.675
Double the intermediate frequency of 21.4 MHz (42.800)
and subtract it from the new frequency –42.800
If the answer is the regular frequency 431.875
then you have tuned to an image.
Occasionally, you might get interference on a weak or distant
channel from a strong broadcast 42.8 MHz above or below the
tuned frequency. This is rare, and the image signal is usually
cleared whenever there is a broadcast on the actual frequency.
RESETTING THE SCANNER
If the scanner’s display locks up or does not work properly after
you connect a power source, you might need to reset the scan-
ner.
Caution: This procedure clears all the information you have
stored into the scanner. Before you reset the scanner, try turn-
ing it off and on to see if it begins working properly. Reset the
scanner only when you are sure it is not working properly.
To reset the scanner, turn it off then turn it back on while holding
the
2 and 9 keys. CLEAr appears.
20-313.fm Page 33 Friday, January 7, 2000 3:09 PM