Private citizens could now use a tabletop receiver with special tuning crystals to pick up local police, fire, and ambulance calls. Users could also eavesdrop on the chatter at air traffic control centers and emergency weather channels. Modern digital police scanners no longer require tuning crystals to pick up these remote conversations. At BestReviews, we use a combination of consumer feedback, independent lab testing, and expert interviews to provide readers with the most unbiased shopping advice possible. If you would like to learn more about police scanners and how to choose the right one, below are some important information to consider. The channel capacity of a mobile unit exceeds that of a handheld in most cases, and the controls tend to be easier to use. On the downside, certain channels could be highly distracting to drivers. Perhaps you want access to a radio scanner while walking through your neighborhood or hiking in a remote location. Many handheld scanners are the size and weight of a military walkie talkie, not a compact smartphone. Handheld scanners generally offer a smaller range of channels than other model types, but they easily pick up local police and fire broadcasts. Neighborhood crime watch volunteers and those who travel alone at night may find a handheld scanner quite beneficial. Desktop scanners, also known as base scanners, are perhaps the most popular choice among amateurs. A desktop scanner sits on a flat surface and runs an electronic scan through all of the local channels selected by the user. When a channel becomes active, the scan stops until the broadcast is over. Owners have the option of locking on a particular channel for specific information or locking out channels that are either inactive or continuously on. Some desktop units include an internal antenna, but others require a booster or external antenna for maximum performance. The most advanced radio communication systems use digital signals for both transmitting and receiving information. While many digital police scanners can receive analog and trunked frequencies, the reverse is definitely not true. An analog or analog-trunking police scanner cannot translate digital broadcasts. Digital transmitters fall into two camps: Phase One and Phase Two. Potential buyers should learn which police scanner online of digital transmission their local agencies use before investing in an advanced digital model. To address this issue, some transmitters bundle multiple frequencies to form a trunk line. We liken this to the older analog telephone system: if one outgoing frequency is in use, the transmitter automatically searches for the next available frequency in the bundle. The same holds true for incoming transmissions from police scanner online cars. Because these frequencies change so often, only scanners designed for trunked systems will work. Before you buy a trunking scanner — analog or digital — make sure your local agencies use trunk lines. An analog-only police scanner can receive a number of local radio transmissions. This applies to rural areas and smaller cities in particular. Investing in a basic analog police scanner makes economic sense if the user is aware of these limitations and if local agencies have no immediate plans to upgrade. How much should you pay for a police scanner. Of course, if your local agency has upgraded from analog to digital, the cost of an analog scanner is a moot point. In this scenario, you would need a upgraded scanner in order to pick up any signals at all. Similarly, scanners with the ability to receive trunked signals are going to cost more than basic analog models. Digital scanners with analog and trunking capabilities are the best, but these sit at the top end of the pricing spectrum. Many medium to large municipalities still use analog or analog-based trunking systems, as digital upgrades are expensive. Since the passage of a federal communications law in 1934, almost all radio frequencies are considered public. The exceptions are encrypted military channels and frequencies used for smartphone communication. As such, agencies and individuals using radio-based communication devices have no expectation of privacy. Some scanners can receive wireless baby monitor transmissions, in-store employee communications, and other sensitive information. Nevertheless, owning and operating an unmodified police radio scanner is legal in the U. However, as we mentioned above, some states prohibit the use of a mobile scanner while driving. Using scanner information to aid and abet a crime is also illegal. Because public agencies are fully aware that the public could be listening in, they sometimes use code language or other channels of communication to protect sensitive information. This is legal, and in fact, both dispatchers and responders are trained to maintain professionalism during all publicly accessible transmissions. Because of this, some first-time scanner owners are disappointed by the lack of drama behind most dispatch calls. Are police scanners legal to own in the U. Yes, police scanners are just as legal to purchase and use as any other radio receiver. However, some states forbid scanner use while driving. And, of course, you may not use information gathered from a scanner to aid criminal activity. Why should I invest in a police radio scanner. You may want to buy a police scanner for personal or professional reasons. Exchanges between the dispatcher and the emergency crew help the owner know precisely where the incident is located and what precautions he or she may need to take. Do I need any special licensing or registration to operate a police scanner. Why should I buy a police scanner when I can listen to streaming broadcasts online or through an app on my smartphone. While a free website hosted by radio scanner police scanner online or scanner manufacturers does provide access to popular broadcasts from around the world, the content is limited compared to what an actual scanner can pick up. Many people buy scanners so they can hear local police, fire, and ambulance communications — not just real-time emergency calls in cities such as New York and Chicago. What police scanner online I expect to hear during a police scanner listening session. Both officers and dispatchers are trained to remain as professional as possible on public airwaves. These codes vary from agency to agency.