GRE PSR-500 Owner's Manual page 132

information about scanning in the specified areas. We also
suggest www.radioreference.com, which includes an extensive
database of conventional and trunked radio system data for
locations all over the USA and the world.
One of the more enjoyable aspects of the scanning hobby is
finding new frequencies on your own. Your PSR-500 includes
powerful Limit Search (LMIT) and Service Search (SRVC) search
capabilities that will help you find active frequencies in your area,
and a Spectrum Sweeper (SWPR) that quickly searches through
selected frequency bands to find nearby transmitters.
PSR-500 User Manual Page 132