Playing with Fire

Scanning with Ed O'Connell

By Michael J. Legeros


This month, the subject is scanning. Our guest is collector and radio hobbyist Ed O'Connell. Also this month, your answers to my question of "what was last year's best Code 3 model?" More on that later.

Ed O'Connell is a part-time emergency medical dispatcher for a two-and-a-half county area in northern New Jersey, as well as an EMT and licensed amateur radio operator. He's also a builder of scale emergency vehicles, and serves as the secretary, treasurer, and newsletter editor of the Metropolitan Miniature Fire Apparatus Association. He's been interested in scanners since first volunteering with his local rescue squad in 1980.

Mike: Ed, what is scanning?

Ed: Scanning is short for scanner monitoring or monitoring two-way radio traffic using a scanner. Scanning is also hobby enjoyed by many people who are interested in knowing what is happening around them. Some may be on and off-duty emergency service providers who want to keep abreast of what is occurring in their town as well as in neighboring communities. Others are radio hobbyists and ordinary citizens who want to hear news as it is happening, or want to be in on the action from the comfort of their living room.

Scanning is a great way to be notified of an emergency situation that may affect you, your family, or your town. You may learn about an evacuation order due to an approaching severe weather situation, a hazardous material incident, or a rapidly spreading fire. These days, being prepared is not an option. Having a few extra moments notice can make a big difference.

M: What is a scanner?

E: A scanner is a type of radio receiver that became popular in the 1970s and that rapidly changes channels looking for radio traffic on specific frequencies. Unlike your favorite broadcast AM or FM radio station, which constantly sends out a signal, two-way radios use a particular frequency for a short time and then it is dormant until the next transmission.

In the early 1970s, multi-band portable radios received broadcast AM/FM as well as other popular monitoring bands that included public safety frequencies. Users would tune around the band to find their local police or fire frequency. Unfortunately, this was the only frequency they could listen to at that time, and if nothing was happening, the radio was silent.

M: So in order to find any action, the user had to manually tune up and down the band looking for activity?

E: Yes. The scanning radio, or scanner, was developed to repeatedly sample a set of specific frequencies, stopping if it detected a signal and resume scanning after that signal stopped. Early scanners were crystal-controlled, requiring one for each channel you wanted to monitor. Most crystal scanners had eight channels; others were available with four, six, or ten channels. Crystals cost about $5 each back then, so if you wanted to listen to many frequencies, it tended to get expensive. It also meant swapping out the crystals from time to time if you liked monitoring more frequencies than the scanner had channel capacity.

M: When did programmable scanners first appear?

E: Programmable scanners were developed in the early-1980s. Crystals were no longer needed and changing frequencies was as simple as pushing a few buttons. This was great news for those who liked to monitor lots of frequencies, or several sets of frequencies, such as when traveling or during special events or certain times of the year.

As communications technology advanced quite rapidly through the rest of the century, newer scanners added new bands such as the 470-512 MHz T-band and the 806-956 MHz 800 band. Newer features included more memory channels (100, 200, 500, even 1000) divided into manageable 10, 20, or 50-channel banks, as well as the capability of searching within two frequency limits. Searching enabled scanner users to monitor activity over a range of frequencies without having to enter each individual frequency.

High-end scanners offered alphanumeric displays and/or coded squelch systems. Coded squelch is used when different agencies operate on the same frequency, such as two police departments 25 miles apart. A sub-audible tone is carried along with the radio signal. Unless the tone matches the receiver, the channel stays quiet. So if two towns use the same frequency but different sub-audible tones, and you are only interested in monitoring one of them, having a scanner capable of decoding these tones is necessary to keep their transmissions apart.

M: What is a trunking scanner?

E: As existing frequencies became busier, public safety agencies needed additional channels for command and tactical operations. Unfortunately, no frequencies were available in most metropolitan areas. A new technology called trunking was developed to make efficient use of a limited number of frequencies. Since almost all frequencies are not "in use" at all times, several agencies could share the same group of frequencies, each assigned something called a talk group. An entire town could operate on the same trunked system, instead of each agency on its own frequency. Small trunk systems use five frequencies while larger systems can have up to 30. And as usage grows, additional talk groups are added using the same group of existing frequencies.

M: Can you give an example?

E: Let's say your town has separate dispatch and operations frequencies for police, fire, and EMS. Thatís six channels right there. Add additional frequencies for public works, animal control, the street department, the water department, the senior citizen's bus, and some extra fireground and detective channels, and it adds up. The frequencies might be on different bands as well; police on UHF, EMS on VHF, fire and other municipal services on low band. Because of the broad range of radio spectrum covered, interoperability is impossible without having the other agencyís radios in the vehicles.

M: How do trunking systems work?

E: In a trunk system, a control channel maintains the status of the system through a computer. The remaining frequencies are used for voice traffic. Each radio is assigned to one or more talk groups. Talk groups are virtual channels; the voice frequencies are like chat rooms. When a radio user keys the microphone, the computer sends a signal to the other radios in that talk group and assigns an available frequency to use for that transmission. Once the message is sent, and the frequency is no longer in use, it becomes available again. A reply may or may not be on the same frequency. If all frequencies are in use, a busy tone is sent to the user keying the microphone, and he has to wait until a frequency is free. Different priorities can be assigned to talk groups, so police, fire, and EMS have priority over public works, animal control, and the senior citizen's bus.

M: What if your scanner can receive the trunking frequencies, but isn't a trunking scanner?

E:  Most scanners are capable of monitoring the frequencies used by trunk systems, but do not have the capability of following the talk groups. In those cases, users scanning through the frequencies will hear fragments of conversations of all the users of the system, as well as the computer-generated data noise on the control channel.

M: Can all trunking scanners tune into all trunking systems?

E: Not necessarily. There are three main analog trunking system protocols used in the United States. All three use proprietary infrastructure, and are not compatible with each other. Motorola, the most popular, has what they call Type I, Type II, and Type IIi systems, which is a hybrid between the first two. EDACS (GE, Ericsson, M/A-Com) is the second most popular, followed by LTR (EF Johnson), which is mostly used by businesses.

If you want to monitor a trunked system in your area, make sure you have the proper scanner by knowing what particular system(s) are used. Not all scanners can follow all systems and spending a few hundred bucks on the wrong type of scanner can be a costly disappointment. I know, it kind of happened to me. The neighboring town uses a narrow-band EDACS system and my two primary scanners are not compatible with it. They can follow an EDACS system, just not a narrow-band one. But these two scanners have several of the features I need, so I had to sacrifice monitoring this one town.

M: What is a digital trunking scanner?

E: The latest top-of-the-line scanners are analog trunking models with added circuitry to receive digital signals. Several years ago, the Association of Public-Safety Communications Officials (APCO) supervised the development of a digital communications technology called Project 25. Interoperability between users was a key initiative. They also wanted to avoid the proprietary system issues that occurred with analog trunking. APCOís Project 25 established a standard for digital radios that all manufacturers had to meet to assure interoperability. Digital technology makes more efficient use of the radio spectrum by allowing closer channel spacing than analog communication. The radio converts the voice message into a digital packet and the receiver converts the digital information back into voice. Analog scanners lack the circuitry to convert the signal back to voice, so transmissions sound like static.

M: Are digital trunking systems catching on?

E: Digital public safety communications isnít widely used right now, but some agencies have adopted the technology. Others are reluctant. Like any new technology, digital systems have their detractors. Some users have complained about audio and signal quality, other users have questioned the reliability of the systems. Since digital systems are new, it is also an expensive project for a town to purchase all-new equipment. If digital systems are in use in your area, you must have a digital scanner to monitor them. Digital-capable scanners are relatively expensive, but as demand increases, prices should come down.

M: How does a buff start scanning?

E: Itís as simple as finding out the frequencies used in your area, getting a scanner capable of monitoring those frequencies, and then sitting back to enjoy the action. Scanning is a dynamic hobby; the more you participate in it, the more you quickly learn about it. Your first scanner can be a lower-end model. In fact, an entry-level scanner is the best bet for a newcomer, as programming the advanced models can be a bit tricky and time consuming. You can get a good basic scanner for under $100. The latest digital-capable scanners cost around $500.

M: Where can they find frequencies?

E: There are many places where frequency information is available. Numerous books have been published; some are much better than others. Scanner Master publishes several excellent regional frequency directories edited by local hobbyists. The directories list not only the frequencies, but also the actual channel usage, and are broken down by state then by county. Some listings include coded squelch information and even vehicle numbering schemes. The old stand-by book, Police Call, is available in several volumes covering several states. The book contains a vast amount of raw frequency data arranged by state and then by town. While the information is good, it can be difficult to determine the use of each frequency listed.

The internet also has numerous scanner-related discussion groups with links to various sites with frequency information. As with books, the quality of the information varies widely.  Search the internet for frequencies and discussion groups. Yahoo Groups has many such groups under the topic hobbies/amateur & ham radio. Many of the groups have links to frequency sites. A good website for frequency information for all areas of the country is Radio Reference.

M: Are scanners against the law in some places?

E: Scanner laws vary widely from state to state. Some states have no restrictions, while others are quite strict, especially regarding mobile or portable use. Some states even require a permit. Check if there are laws applicable in your area. A good radio-related hobby shop should be able to point you in the right direction. Also ask other area scanner users or your local police department about laws regarding scanner use. In many states, licensed amateur radio operators are permitted to have mobile scanners.

If mobile or portable scanners are permitted in your area, be discrete with their use in public. Strolling through the local mall with the security channel blasting from your belt is a pretty stupid way to attract a lot of unwanted attention, especially in this day of heightened awareness of homeland security. Keep the volume low or consider using headphones or an earpiece to avoid drawing suspicion in certain places.

M: Are there laws against listening to certain frequencies?

E: With the exception of cellular and cordless phone frequencies, and encrypted communications, you are entitled to receive just about any type of radio signal as the airwaves are considered a public place. Early cellular and cordless phone users believed that their devices were secure. What they didn't realize, and what the cell phone companies did not tell them, was that they were actually using radios that transmitted unsecured signals in all directions.

When a high-ranking Washington politician was overheard on a scanner saying something on his cell phone that later came back to bite him, the powerful cellular telephone industry association lobbied for the passage of an anti-monitoring law in the late-1980s. At the time the law was seen as a serious threat to the scanning hobby. Fortunately, that wasn't the case. But the result of the law is the reason cellular phone frequencies are excluded from scanners sold in the United States.

The radio spectrum is for the most part a public place. Two-way radio users need to remember that they shouldn't say anything over the air that they wouldn't want anyone to hear, or that they wouldn't want to see as the top story of a newspaper or newscast.

M: What are ten-codes and what is "plain text"?

E: Back in the early days when public safety radio frequencies were located just above the AM broadcast band, police departments used codes for routine messages, partly for brevity, and partly for some bit of secrecy. "10-4, 10-8, 10-12," and so on. However, it didn't take long to figure out what they were saying.

Because there is no standard set of codes, using "plain text" or the actual words to speak your message is favored. This avoids confusion when two agencies need to communicate with each other and the meanings of their codes are different.

For example, if a police officer says "10-8 at the 10-20, 10-13" and means "On scene of an armed bank robbery in progress, send assistance," another law enforcement agency might translate his message into "Out at my home for meal break." While that is an extreme example, you can see why plain text messages are preferred.

M: How many scanners do you have?

E: I currently own five scanners. My primary scanners are a Radio Shack PRO-2067 mobile and a PRO-92 portable that I keep in my truck. Both are 500-channel analog trunking scanners that have the same internal workings in different cases. Both can be cloned with each other; can be programmed through a computer, and feature an alphanumeric display and tone-coded squelch decoding. In my computer room/office, I have a RELM (Regency) MS-200 200-channel computer-programmable conventional mobile unit with alphanumeric display and tone-coded squelch decoding. In my hobby workshop, I have a Uniden Bearcat 200-channel conventional scanner with CTCSS decoding only. The final scanner, currently in reserve status, is a RELM HS-200 portable, which has tone-coded squelch decoding but no alphanumeric display. I also have scanning capability in my amateur radios in my truck.

M: What else can scanners monitor, in addition to emergency radio traffic?

E: Railroads, boats, aircraft, amateur radio, NASCAR, snowplows, taxi companies, and towing services are also popular monitoring subjects. In fact, the monitoring possibilities are almost endless. If radios are used, and you know the frequency, and the frequency is within your scanner's operating range, you can listen to them.

M: Do you have a favorite scanner?

E: Actually, it hasn't been invented yet. I've made do with each of the scanners I have owned. But in each case, I had to make some sacrifices, because no one scanner has had all the features I want in one package.

M: Do you have a favorite scanning site?

E: Strong Signals is a great resource for questions about scanners and scanning in general. There is a ton of information there gathered from various sources.

M: And what is your pick for the best Code 3 release from last year?

E: The Harrison Mack CF pumper. I love the classic lines of the Mack CF. While both versions were very attractive, Iíd tip my favor to the all white one. Simple, yet classic elegance.

Ed O'Connell can be contacted at Mike Legeros can be contacted here. Both welcome your comments, questions, or corrections.

A version of this column originally appeared at Code 3 Collectibles.


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Copyright 2017 by Michael J. Legeros