Scanner Basics and Frequently Asked Questions
How far will I be able to listen?
Distance depends on
too many factors to provide an easy answer, such as the elevation of your
home, whether there are hills or other obstructions between you and the
agency you wish to monitor; the transmitter power of the agency you wish to
listen to, etc. These and other factors all play a part. Generally
speaking, with a handheld or desktop scanner you can hear in a 10 to 20
mile radius, but that's not set in stone.
What is Trunking?
As public safety agencies and businesses grow they require more and more
radio frequencies for their operations, consequently available radio
spectrum has become more valuable and more difficult to find. To help
resolve this problem, radio manufacturers developed trunking which works on
the same principle as a trunk telephone line. Let's take for an example the
city of Worcester, Massachusetts. This mid-size city used to have two or
three frequencies for the police department and two or three for the fire
department as well as one for public works and one for parks. Now, with
their trunking radio system, they have upwards of 50 or 100 groups of users
on 10 radio frequencies. Here's a listing of just some of their
04-041 Fire Ops A North
04-042 Fire Ops B South
04-044 Fire Dispatch
04-045 Fire Administration
08-041 Police East Patrol
08-042 Police West Patrol
08-044 Police Traffic Enforcement
09-006 Police Auto Theft
12-041 Water Department
12-042 Water Filtration
12-043 Sewer Department
12-044 Health Code/Sanitation
12-045 Street Department
12-056 Snow Emerg./Plowing
12-083 Traffic Signs & Signals
One of the frequencies in the system is the control or data channel,
continuously broadcasting a stream of computer data that sounds like a
buzzsaw over the air. Every time a police officer, a firefighter or a
sanitation worker presses his microphone button an instantaneous computer
command is sent out to all the other users within that person's radio group
to move to one of the nine available voice frequencies in the system. The
channel the group is assigned is almost completely random so there's no way
to follow a communication unless you have a trunking scanner that works on
a principle similar to that of the actual two-way radio. Hence, the
TrunkTracker. One moment an officer in the police east side traffic
division may be calling his dispatcher on one of the nine frequencies, and
seconds later that dispatcher may reply to that officer on a completely
different frequency. So now, a small group of radio users, such as the
Water Filtration division, can effectively have their own radio channel.
It's not a frequency per se, just any one of the 9 available radio
frequencies as long as it's not in use by another talk-group of users.
The two major types of trunking systems are manufactured by Motorola and by
M/A-COM (known as EDACS). A popular business trunking technology is known
as LTR. Most, but not all, public safety trunking systems operate on the
800 MHz band. As the technology has evolved over time, each manufacturer
has some different flavors of their trunking system. With Motorola you'll
hear about Type I, Type II and IIi. Type I requires something called a
fleet map to work properly (although these systems are gradually being
phased out). EDACS has narrowband, wideband and SCAT. There are a number of
LTR style systems, including one known as MultiNet for public safety (there
is no scanner today that can track it) and Passport which is primarily for
business communications. There is also some encryption on these systems
which makes it impossible to monitor. All of it sounds very complicated and
it can be, but here we specialize in providing you with the information to
make it easier to set up trunking for your area and once it's done right
it may never have to be touched again. Note: EDACS, MultiNet and Passport
are trademarks of their manufacturers.
Trunking systems can be complicated to program for novices (although our
BuTel software makes programming much easier), but you'll find that
scanning these trunked systems to be more pleasurable, interesting and
informative than ever before. You can hear both sides of a conversation and
you can listen in to just those groups which interest you.
What is Digital and APCO-25 all about?
Can I listen to cellular phone calls? Can scanners be modified to
listen to it?
Just like your cell phone, a digital two-way radio system converts voice
into ones and zeros and transmits this data to another radio which decodes
the information so the voice communication (sometime sounding a bit
robotic) is heard on the other end. Older public safety radio systems are
often being replaced with the new digital systems. There is no way to
upgrade an older or non-digital scanner. You must buy a digital scanner
(such as the Uniden Bearcat BCD996P2 desktop model or 436HP portable.)
There's now digital Phase I as well as the newer Phase II. It's important
to find out what is being used in your area and we can help (call or
email us) or
check out policescanners.net.
Digital scanners decode APCO-25 non-encrypted transmissions automatically
(encrypted communications cannot be decrypted, it is not legal and not
possible). A few agencies operate in encryption full time. There are also a
few non-standard digital radio systems that are not monitorable at this
time such as OpenSky and European Tetra. Many agencies also used MDT's
(mobile data terminals), the computers in the patrol cars as well as cell
phones for private communications. Cell phones, mobile data terminals, the
few non-standard digital modes and particularly encrypted communications
cannot be scanned. There is no scanner for them. Again Scanner Master can
help you determine what is being used in your area.
What are PL and DPL (private line & digital private line) or CTCSS
and DCS sub-audible tone codes?
Many scanners have the ability to program both a frequency and a
sub-audible tone code (PL/DPL). It's not required that you use it but it is
recommended if you have the PL/DPL information. As many agencies and
businesses share radio frequencies they use these codes to insure that they
only hear others within their department or company. You can do the same.
PL helps limit interference by pre-selecting only those transmissions your
most interested in and filtering out unwanted conversations. PL data is not
always available but most scanners today provide a method of automatically
determining the PL or DPL in use.
By federal law monitoring private phone conversations is prohibited. No
scanners made in the last 10 years have been capable of monitoring cell
phones or are capable of being modified to do so. Most cellular phones are
now TDMA or CDMA digital which is completely different from APCO-25 digital
What accessories do you recommend?
What is this Close Call feature of some of the Uniden
Close Call allows the scanner to instantly tune to most any standard
(non-cellular/Nextel) radio transmission within your line-of-sight, or in
some cases even further. So, if you're at a mall, a sporting event, or
happen by an accident scene for example and you don't know the local
security, event or police/fire/EMS channels, Close Call will automatically
tune your scanner to the frequencies being used. If you've been waiting for
the right time to buy a new scanner, buying a scanner with Close Call is a
great reason to finally make the move.
How can software help me with scanning?
Other than some of the low-end scanners, most scanners today are computer
programmable. Using a serial cable and software you connect your scanner to
your PC and then you can create multiple files for different areas or
events to which you might take your radio. For trunking scanners and/or
scanners with alpha-tag capability, programming on a computer (usually in
spreadsheet like form) is considerably easier than programming on the
scanner itself. More advanced software allows you to also control your
scanner from the PC and log activity, record audio, and do much more than
you could ever do on your scanner alone. Uniden includes demo software with
their scanners but Scanner Master recommends the BuTel ARC (Advanced Radio
Control) software which is widely considered the world's best. It's
extremely easy to use, loads and works seamlessly with your PC, and it's
very powerful and feature rich.
Antennas - There is no better way to improve reception, whether for
base or mobile scanning, then by adding an outside antenna. For home or
office scanners we recommend a base station antenna, such as the Discone
for all-band monitoring. If you want to really improve performance on a
single radio band, check out our professional base station antennas, either
omnidirectional or directional for most receiver gain. Aiming a yagi (beam)
antenna at a station or region that uses a common band (such as 800 MHz
trunking or 460 MHz UHF) will pull in signals you never dreamed of. For
mobile scanners we urge you to mount a mobile antenna somewhere on your
vehicle. Getting the antenna out from under the steel roof of your car or
truck will provide a huge improvement. Not everyone wants another antenna
on their car so we offer various types and mounting options. For portable
scanners you can buy antennas tuned to specific bands (such as 800 MHz) for
improved trunking performance for example, but other bands will suffer.
Software - For all scanners with a PC connection we highly
recommend scanner software which will make programming easier and operation
more enjoyable. If you're not convinced go online and check out the demo
software from Butel that we offer for many models.
It is 100% legal in the United States to purchase, own and operate a
scanner radio with a very few minor exceptions. We note that because radio
law sometimes, but extremely rarely, changes, and because we are not
attorneys, you should check your state, local and federal laws if you have
There are a few states that have laws on the books regarding the use of
scanners in motor vehicles. Kentucky, Indiana, New York and Florida come to
mind. There are a few additional states where it's illegal to use a scanner
in the furtherance of a crime. Click these links below (which may or may
not be up-to-date) for further information:
It is illegal to intercept cordless phone communications (most cordless
phones today are spread spectrum and cannot be monitored anyway. It's also
illegal to monitor cellular phone conversations and for the last 10+ years
the major scanner manufacturers, by federal law, have not produced a
scanner capable of monitoring the cell phone band. At any rate, because
99.9% of all cell phone calls now are CDMA, GSM and other highly advanced
types of digital (not APCO-25 digital), cell phone calls couldn't be
It is also illegal to decrypt encrypted communications. Most public safety
communications that use DVP/DES and other types of highly-sophisticated
encryption couldn't be decrypted without years of work and a supercomputer
anyway. Luckily, relatively few public safety agencies in the U.S. use such
systems. In other parts of the world, particularly we know in Europe, the
public safety radio systems cannot be monitored.
Scanners are a well regarded and respected tool for the news media, public
safety agencies themselves, and for the general public. Americans like to
be in the know. They like to be aware of what's going on around them and
they like to help the police and fire services whenever possible, by
reporting crime, fire, and the like. Knowing what the local authorities are
doing and perhaps helping (without interfering -- very important) after
having heard something on-the-air, benefits us all.
So scanners are completely legal to own in your home, on your person, and,
in almost all states, in your vehicle. They help you build a healthy
respect for the job our public servants our doing while at the same time
keeping you in the know. Buy a scanner radio today and be informed and
How Scanners Deliver the News as it Happens
This is a long way of asking, "Why are scanners so great?" Or, "Why are
scanners such a useful and enjoyable product for everyone? There are many
reasons why and below we've just begun to cover them. We all want to know
what's going on around our city, our nation and the world, but it's the
local news that's most important to us. It's what's happening in our
community, in our neighborhood, that we most want to follow. We can watch
TV, read a newspaper or look online for our news. But in all cases it takes
time for a reporter/photographer to go to the scene of a fire or a bank
robbery and report. With cutbacks in news organizations of late, most
public safety incidents won't be reported on at all, or the report will be
delayed. And, if you're just curious why that police car raced down your
street, you're likely never to know by just relying on news services.
With a scanner you solve all these problems. With a scanner you hear the
dispatch* and then can generally follow the police and fire communications
as they report from the scene.
So with a scanner you learn of the news "as it happens" rather than
relying on some news service to, perhaps, go to the scene and file a
report. The media relies on scanners, too, so by using a scanner you'll
know right when your local TV and radio station knows when something
important is happening.
With a scanner you'll also be entertained. Let's face it, listening to
police chases live is unbelievably exciting. Hearing firefighters call for
more water pressure as they're inside a building fighting a fire is
thrilling. Hearing planes and trains be dispatched and routed is just plain
fun. And in all cases you're admiration for the jobs these public servants
and private professionals are performing only grows while your knowledge
and understanding of their work increases.
You can have a scanner on in the background while you watch TV. Some
people even go to bed listening to a scanner at night and, over time,
instinctively know and wake up when something exciting or important is
happening - you can tell by the tension in the voice of the dispatchers and
officers in the street who are communicating.
Particularly for kids, when you're listening to a scanner you're
practically riding along in that patrol car or you're in that fire truck
racing to a scene of a fire. It's really mesmerizing, entertaining,
informative and educational all at the same time.
And, particularly for adults, perhaps those who are concerned about
crime in their neighborhood or dry brush around their homes during the fire
season, a scanner will keep you abreast of what conditions are in your
area. Are police responding to suspicious persons on nearby streets? Do you
hear the fire department being called out to hose down homes in the
development a few blocks away? This is invaluable information that you can
find nowhere else or not nearly as quickly. A scanner radio does it
So we hope you'll consider buying yourself or a loved one a scanner
today. For information, for entertainment, for peace-of-mind, and more.
There's nothing like a scanner.
Copyright 2015 Richard Barnett, Scanner Master Corp.