RadioReference.com provides a list of police scanner frequencies for many local counties and cities in the United States. RadioReference.com also lists many other radio frequencies used by emergency services, federal departments, businesses, airports and ham-radio stations.
RadioReference.com lists radio frequencies under the Databases section of the website, and it provides a map to select the desired location and offers detailed search options, such as Frequency Search by Metro Area and FCC License Proximity Search. RadioReference.com also provides radio frequency listings for many other countries, including Canada, the United Kingdom and Australia.
Individual listing pages on RadioReference.com also provide links to Internet rebroadcasts of select frequencies on Broadcastify.com. Broadcastify.com also provides maps and lists of live feeds on its homepage. Certain mobile apps for smartphones provide live feeds of police frequencies, such as 5-0 Radio Police Scanner, according to App Advice.
As of 2015, many police frequencies are no longer available to public listeners as police departments switch to encrypted radio systems, reports The Verge. Journalists are particularly upset when police departments encrypt radio systems because they have long relied on open frequencies to keep track of breaking police stories. However, police departments argue that criminals use open frequencies to plan crimes around the movement of police.