Looking For A Digital Radio Scanner?
The features and functions available in digital radio scanners can make the selection process seem complicated. Sales people can easily detect an absolute novice in search of high tech devices. Sales commissions can cloud the morals of some sales people and you can leave with some high-priced overly complicated scanner that leaves you feeling lost. Do some research and you will keep the salesperson more honest. If you are purchasing online, research is even more important.
The first step in researching digital radio scanners is to learn the basics. Digital radio scanners are designed to receive and process digitally encoded signals transmitted between various two-way radio systems in public use. The use of digital signals, unlike the recent mandated changeover of television to digital, is voluntary. Both older analog signals and newer digital transmissions are in use. All currently available scanners still receive the analog signals.
Non-encrypted digital signals meeting the APCO P-25 standard can be processed by digital radio scanners. Encrypted signals, cell-phone messages and portable radio digital signals are not processed by digital scanners. Digital radio scanners cannot be modified to process cell-phone messages. Prior to 1994 it was possible to buy scanners that could receive cell phone and cordless phone signals. Since that date an FCC rule has required ALL Scanners Sold in the USA to be Cellular frequency Deleted (Blocked).
FCC regulations do not prohibit the sale, ownership or use of digital radio scanners. Scanners must be FCC approved, of course. Some state and local governments have laws in effect limiting scanner use in vehicles or while committing a crime. Scanner regulations include a clause against scanned use to "break existing laws." Checking local rules is advised and the information presented is not legal advice.
The basic functions of digital radio scanners are quite uniform over the many brands and models available. Buying a high-priced scanner will not mean better reception and a low-priced scanner will have as good (possibly better) reception. Price differences are often based on special features or additional band coverage.
One common complicated-sounding technical term is trunked signals. A trunk is a pool of frequencies (channels) shared by multiple users and departments. The advantage is that all frequencies share the load. No one frequency carries almost all the transmissions while others remain unused. Communication can be over any of the trunked frequencies at any time - making following the communication with a scanner almost impossible. Digital radio scanners with trunk support have built-in technology to make use of some of the many versions of trunk lines.
A couple other terms you will encounter are PL and DPL. Some digital radio frequencies are shared by two or more departments. Each department's transmissions begin with a PL tone that specifies the department. Digital radio scanners with the feature can be set to ignore or accept transmissions from specified departments.
The close call feature will detect a transmission within a close distance (two hundred yards... Etc) and jump to that frequency even if it is not programmed for it.
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