Police Jurisdictions and Mutual Aid channels

When you buy a scanner, especially if you have us do your programming, you may hear many different types of police agencies. There are the commonly known departments like city police departments and County sheriff’s offices as well as Highway Patrols. There are also many other federal, state, county and local police agencies.

Police agencies’ jurisdictions vary, based on the type of agency, the location they are in and the type of situation. Usually a state agency has jurisdiction anywhere in the state but usually does not enforce local ordinances inside of cities. A County officer similarly has jurisdiction throughout the entire county but again may not have the ability (absent a contract to do so) to enforce city ordinances. Local police usually are restricted to working within their own borders. County and Local police also have the ability to pursue outside their jurisdiction and usually to make arrests for serious violations outside the community. These laws vary from state to state and some agencies are contracted to provide services in other jurisdictions. For instance a small town might contract with the county or state or even a neighboring town to provide primary police protection, that other agency’s police can then enforce the ordinances for each town.

Federal agencies include the FBI, US Marshall, or DEA. There are many federal law enforcement agencies that are tasked with different responsibilities. Some are responsible for building and campus security at federal facilities and bases. The most well-known include the Customs & Border Patrol (CBP) that protect the nation’s borders, the Federal Bureau of Investigation (FBI) and Drug Enforcement Administration (DEA), both responsible for specific law enforcement actions. There are Military Police agencies at most major bases around the world. The Navy also has police and security aboard large vessels like aircraft carriers as well as bases around the country. Most federal law enforcement agencies use encrypted radios for communications, but sometimes non-scrambled radios are used.

Once agency we should mention is not a law enforcement agency at all. Every flyer’s favorite agency, the Transportation Security Agency (TSA) is not a law enforcement agency. TSA officers do not have arrest powers, they refer actual enforcement actions to the local police authority for the airport in question. If an illegal item such as a weapon or drugs, are found the arrest is made by the local or airport police, not the TSA. They do have the authority to deny one access to the transportation they protect. While most associated with airport entry protection they also appear at rail and bus stations occasionally, usually along with local or federal law enforcement agents.

At the next level is the many state law enforcement agencies include the State Highway Patrol, State Police or State Patrol agencies. Like the famous California Highway Patrol of “CHiPS” TV show fame, many states have Highway Patrols. Some states have “State Police” (common in the Midwest and East). Some are called the “State Patrol”, like those in Wisconsin and Minnesota.

State police officers are often called Troopers and often have a more military rank structure with Major’s and Colonels instead of Chief’s at the top end. Most state agencies primary responsibilities include highway patrol, usually on the state’s Interstate and other major highways. Other agencies fulfill support roles for county and local agencies like crime scene processing or manpower for major events. Most of the time State Police agencies do not fulfill local police patrol responsibilities off the highway like city and county police do. Occasionally State Police agencies will do local patrol for communities that cannot support their own police. For example, for years the Illinois State Police patrolled the city of East St. Louis due to the extreme financial distress the city was in at the time. In Massachusetts and Connecticut they often do not have county police agencies so the State Police step in to assist local agencies that elsewhere would be done by the Sheriff’s Police.

There are also other state law enforcement agencies on and off the highways. Some states have a separate police agency for trucking regulation, DMV enforcement, Fish & Wildlife, and other specialized responsibilities. There are also state facility police agencies, like the California State Police (separate from the Highway Patrol) that patrolled the state capitol complex.

All states have Counties, although Louisiana calls them Parishes and Alaska calls them Boroughs. Most of these states have County (or Parish) Sheriff’s Offices (SO’s). Sheriff’s Offices are usually responsible for road patrol, court security and corrections. In smaller counties there are a single County Sheriff’s Office to handle these three tasks. There may be a small Sheriff’s office with the elected Sheriff and a couple deputies to deal with all this. Larger counties may have separate Patrol, Court and Corrections departments. Some counties also have other law enforcement agencies for specialized purposes such as Conservation, County Hospital or Forest Preserve districts among others.

In small counties the Sheriff’s Office might be the only law enforcement agency in the county, there may be no cities in the county or those that exist may not have their own police departments. If an incorporated community has no police department then the Sheriff usually handles law enforcement for the town. Some towns contract with the Sheriff to be their police, often with dedicated officers and vehicles. In some states some or all of the counties have little if any authority. In Delaware and parts of Massachusetts the Counties are pretty much just lines on a map and they do not provide police patrol.

The Sheriff or other county based agencies may also be responsible for other duties such as tax collection, Justice of the Peace, and other administrative services depending on the state and local rules.

Cities, Towns, Villages, Townships (in some states), Boroughs and other municipalities usually have a police department or contract with a neighboring community, State Police or the Sheriff for law enforcement. As a basic service of the municipal government, local police are usually the first response to most emergency situations in the town. They are also responsible for many routine and non-routine services that vary widely from town to town. Local police respond to 9-1-1 calls, document and investigate property and personal crimes, traffic crashes and many other incidents.

There are often specialized police departments for parks, colleges and other schools, public hospitals, and many other taxing districts. Some places even have police departments run by sanitary districts or other large government land owners. In some states in the Northeast there are groups called “Fire Police” which have no actual police power but provide traffic and crowd control at fires and other events.

Local, state and county police departments often participate in Mutual Aid agreements. These allow them to assist each other for emergency and routing incidents and cooperate on incidents that spread over multiple jurisdictions.

OK, so since this is a blog about scanners, what does all this blather mean to me and my scanner? Well, all of these agencies use radios to communicate. If they work together then they need to talk to each other. This is done a couple different ways. The first is by one agency having the other agency’s channels available to them. They could have them added to their own radios or carry a separate radio for that purpose. For example, Mayberry PD might have Mt. Pilot’s channels in their radios.

Another way is to use designated Mutual Aid channels. Most states have some sort of channels made available for police departments to communicate with each other, Illinois has ISPERN and other discrete channels for this purpose. Sometimes this is on a large regional or statewide trunking system like MARCS in Ohio or Palmetto in South Carolina.

Less convenient is the relaying of communications by dispatchers. Mayberry Deputy Fife would call his dispatcher who would call the dispatcher for Mt. Pilot who would then contact the Mt. Pilot officer and relay what Deputy Fife said.

The many large statewide trunked radio systems, like those in Colorado, Minnesota, Illinois, Indiana, Ohio, North Carolina and South Carolina include many shared statewide and regional mutual aid channels to allow multiple agencies to communicate with each other. This allows the Highway Patrol to talk to a Sheriff’s office as well as local police etc.

Before large or regional trunked radio systems, when many states used Low Band (30 thru 50 MHz.) some states had a Statewide Sheriff’s Channel or some other statewide channel or channels that agencies could use to talk to each other. Illinois for example had 39.50, which was called the Statewide Sheriff’s Net. This was a common channel to almost all counties and many city police departments and they could talk to almost anyone else. The Illinois State Police had 42.50, which they used for all State Police Districts and all troopers had that channel. A special switch in the ISP cruisers’ radios allowed them to hear 39.50 and talk back on 42.50, the Sheriff would have the opposite arrangement. This allows each agency to talk on the channel they were licensed for (and that the radio was tuned to) but still communicate with each other. Other states had similar systems. Nebraska had a set of statewide channels for Police, Fire and EMS on 39 MHz.

Eventually Low Band was replaced by “High Band”, usually about 150 thru 160 MHz. and many states replaced the old channels with new VHF channels common to many agencies. Indiana, for example had the old “Plan A” channel of 155.130 (Base) and 154.890 (Mobile) that was a common dispatch channel for many agencies statewide. In addition separate channels were used for police emergencies like 155.475 (the nationwide Police emergency channel) that Indiana called ILEEN and 155.370, which most Midwest states used as “Point to Point”.

Another example was in Illinois, not only do they have a statewide police channel called ISPERN (on the same 155.475 channel as next-door Indiana) but a statewide Fire channel, EMS network, EMA channel and even a channel called IREACH that can be used by any governmental agency to talk to others.

There are some newer nationwide mutual aid channels for police, fire, EMS and mixed operations. Not often used, they are available and detailed in many area’s plans but it is rare to hear them used for the intended purposes. Part of the problem is the clunky naming protocol and huge numbers of channels. V-Fire-31, 8TAC94, UTAC42D and their brethren all are listed in guides but rarely actually used.

Later on, as the large regional and statewide trunked radio systems started being built these systems include many regional and statewide mutual aid channels. Some systems have regional networks that allow any user to talk to any other user anywhere in the area, as well as statewide channels that work anywhere in the state. With the higher capacity of these systems more specific channel assignments can be made to tailor the operation.

Large trunked radio systems do have some drawbacks. They can be complicated to work for many users, and with the bewildering array of channels available that could confuse people to where they may not know what channel to use or how to find it. Like the wide variety of mutual aid channels on VHF, UHF and 800 in the more recent past, the overwhelming choice of channels and confusion about how to access them make it more likely for users to revert to having the dispatcher call the other agency on the phone.

You can dedicate a large chunk of your scanner’s memory to interoperability (big word meaning Mutual Aid) channels and not hear much, if anything for months until one day it starts hopping with a big incident. Check Radioreference.com for the Mutual Aid channels used in your area.

Hamvention Here we come!

Once again Scanner Master will be at the Dayton Hamvention! This is the largest hamfest of the year and we will be in our regular booth, # 3303 in Building 3. Be sure to stop by and see Rich Barnett, Rich Carlson and Gommert Byson of Butel in the booth!

Hamvention is open to the public on 9A-5P Friday, May 17 and Saturday May 18, and 9A-1P on Sunday, May 19 2019 at the Greene County Fairgrounds in Xenia Ohio. On Sunday only the admission is free this year!

Please stop by our booth if you attend this year, we will have scanners and accessories for sale and will be happy to say hi!

Classic Scanners that changed the hobby

We all love scanners, you would not be reading this if you didn’t. There are certain scanners that, much more than others, are so remarkable that they change the market or make a lasting impression on the hobby. Scanners that introduced new features, made other features popular or just were so darn good that they are beloved by the community will be discussed here.

If you have a favorite scanner that you think should be listed please let us know! The ones I discuss are scanners that I think helped define the market at the time and are real game changers. While some are obviously dated and obsolete today at the time they were introduced they really made a huge impact.

There were also a few real duds here and there. Bearcat once made a scanner that you inserted into an 8-track player. For those too young to know what that was, an 8-track player was used to listen to music recorded on magnetic tape held in large plastic cartridges in the days before cassette tapes, they were wildly popular in the 1970’s. This scanner was in the shape of one of these cartridges and had 4 crystal-controlled channels. It was a neat idea but worked poorly.

GRE Designs:

GRE built and designed many scanners for Radio Shack back in the day. Later they developed their own line in parallel with the Radio Shack line. Coincidentally both Radio Shack and GRE closed up operations for different reasons at about the same time and Whistler Group bought the GRE product line. Whistler continued to produce scanners for Radio Shack based on the Whistler designs for a short time and afterwards brought out their own line of WS and later the TRX scanners.

Radio Shack had a great advantage in that they had a huge retail infrastructure around the world and for years sold a wide range of scanners. While most were GRE built even Uniden made some of them.

PRO2004/5/6

The PRO2004 was introduced in 1986 and was probably the most revolutionary scanner of the day. It had 300 channels when 16 was considered average and 50 was considered remarkable. Its wide-open frequency coverage actually caused it to be recalled from stores to have the cellular frequencies blocked, this was easily defeated however, and the radio even had the proper spacing for them. They were coveted by the MilAir listener and helped create a large cottage industry for modifications and accessories. It spawned the PRO2005 and PRO2006 successors, similar in operation but in smaller cases with some other tweaks and additional memory.

PRO43

The PRO43 was introduced in the mid 1990’s and was the first handheld widely available that included the Mil Air band so were coveted by the airshow crowd. With 200 channels one could program in a ton of channels or do a search of the band. The tiny size made it easy to keep in a shirt pocket or camera bag.

PRO96

The PRO96 was the first P25 scanner that worked on the newer 9600 baud trunked systems, together with its mobile cousin, the PRO2096, one could now listen to these systems directly rather than in a conventional mode. It also provided a data source usable with software programs such as PRO96Com and has data detection modes that were well liked by radio enthusiasts.

PSR800/WS1080

The PSR800 was introduced in 2011, just before GRE went out of business. It was rebadged as the Whistler WS1080 soon thereafter and eventually morphed into the WS1088 and TRX-1 Mobile versions of the stillborn PSR900 became the Whistler WS1095, WS1098 and TRX-2. The PSR800 was the first scanner co work on Phase 2 P25 systems and was one of the first scanners with the on-board database and ZIP Code programming.

Uniden – Electra – Bearcat

Uniden Bearcat scanners originated with the Electra line back in the 1960’s and 70’s. After purchase by Uniden they retained the Bearcat branding and designs. Eventually Uniden bought the Regency brand and rebadged some existing Bearcat designs with Regency names.

Uniden became the biggest player in the market. Bearcat scanners have had great success with many groundbreaking designs over the decades. Here are just a few of the ones we think really made a huge difference:

BC-III

The BC-III was introduced in 1975 and was a VHF/UHF crystal scanner that was one of the most popular scanners of its day. It was unusual in that it allowed both UHF and VHF in the same radio in the days when that was not common. The speaker was huge and provided such good audio that years later, when the scanner itself was no longer useful, hobbyists would wire it up to be used as an external speaker for more modern scanners.

BC101

The BC101 was introduced in the mid 1970’s and was one of the earliest programmable scanners. It was programmed by setting the channel switches in a pattern for the specific frequency as listed in the programming guide. While kind of clunky, for the time it was revolutionary to be able to program a scanner without crystals and it had a huge 16 channel capacity.

BC210

The BC210 was introduced in 1977 and was Bearcat’s first direct entry programmable scanner. Imagine in the days when one would buy crystals for each channel, need programming combs or have to look up binary codes in a guide that they were now able to enter a frequency directly into a scanner. It was unheard of!

BC100                                                          

The BC100 was introduced in 1981 and was the one of first mainstream handheld programmable scanners. The first versions had a threaded antenna connector and later versions had a BNC. It used AA rechargeable batteries but they were internally mounted so a screwdriver was needed if you wanted to swap them out. It was a revolutionary handheld scanner that could be keyboard programmed without need of crystals, a new concept at the time.

BC235XLT/BC245XLT

The BC235XLT was introduced in the mid 1990’s and was the first TrunkTracker, it would scan Motorola trunked radio systems on 800 MHz. at the time. Before that one would have to enter the various channels into a scanner memory, lock out the current control channel and make a guess as to the actual users as there was no way to otherwise discriminate among them. The compact form and huge (for the time) capacity of up to 300 channels were huge selling points. The similar BC245XLT that came out a few years later added computer control and EDACS trunking to the mix.

BC780XLT

The BC780XLT was introduced in 2001 and changed the hobby more than almost any other scanner ever had. With 500 channels, the ability to track several formats of trunking, wide frequency coverage (including the Military air band) and great performance it remains a great scanner for many to this day. It was really the cream of the crop of the day.

BCD996/396 Series

The BCD996T was introduced in 2006 and replaced the BC780XLT as the flagship scanner, along with the portable version (BCD396T) it provided P25 reception and bullet proof reception along with up to 6000 channels of dynamically allocated memory. It spawned the BCD996XT and 996P2 mobiles and 396XT and 325P2 handhelds with similar features and carried on the Family arrangement of scanners where a handheld and mobile version were created. The 996/396 series introduced GPS enabled programming as well.

Home Patrol

The HomePatrol was introduced in 2010 and was the first ZIP Code enabled scanner. This truly revolutionized scanning and made it available to the masses who did not want to program a scanner, now they can just enter the ZIP Code to load the channels into the radio.

SDS100/200

The SDS100 handheld scanner was introduced in 2018, followed in 2019 with the mobile SDS200. These use the HomePatrol database but also provide excellent performance on digital simulcast systems. These systems have been the bane of scanners for as long as they have been around but finally a consumer scanner had good performance on them. With the color customizable display and ability to handle almost any type of radio system they will be the top of the heap for years to come.

Regency/RELM:

Regency, like Electra Bearcat, was an Indianapolis based scanner manufacturer that had some well-loved designs, especially in the 1970’s. Best known for its early crystal scanners, they had a large following. After many years they sold their scanner line to Uniden but a decade later came out with a new line of scanners under the RELM name that lasted only a couple years.

TMR-8H

The Regency TME-8H was an 8-channel VHF only crystal scanner from the late 1960’s. It was my first scanner, my dad had bought it for me so I could listen to him when he was working as a police officer in our hometown. We had the local channels at the time and with 8 channels I could hear all the local police and fire operations easily. 

ACTR20-6

The Regency ACTR20-6 was a 20-channel 6-band crystal-controlled scanner introduced in 1975. This was the days when an 8-channel scanner was a luxury, and one could spend more on crystals than on the scanner itself.

AOR

AOR is better known for high-end receivers rather than traditional scanners but some of their products made it to the mainstream scanner market. The AR8000 was the most notable but there were a few others that became popular. AOR receivers do not follow trunking so are pretty much relegated to the advanced hobbyist or specialty uses.

AR8000                                                       

The AOR AR-8000 was introduced in 1994 and was an early full-range and all-mode scanner with 1000 channels. It covered just about anything with antennas at the time, covering the entire shortwave, VHF and UHF bands, from 500 KHz. To 1900 MHz. It did most analog modes, including CW and SSB and was computer programmable and controllable. It was popular to use with the OptoElectronics Scout recording frequency counter and one could buy a special cable and battery door (that allowed the cable to plug into the radio) to connect the two devices. This allowed one to get a hit on the Scout and hear the traffic on the AR8000. While current scanners have the CloseCall or Spectrum Search these days this was revolutionary at the time. It was also known to have great sensitivity and worked well on the cell bands.

Other Brands:

There were many other popular brands like Robin, Midland, Cobra, RCA and others. Some were rebadges of radios made by Regency, Bearcat or GRE but many were (or are) their own designs. Many department stores of the day like Montgomery Wards, Sears and others also sold Regency or Bearcat scanners rebadged with the retailer’s name.

Close Call is not a programming option

One of the questions we often get here at Scanner Master is how I can listen to whatever is around me. While the ZIP Code scanners are the way to go for this some people think that by using the Close Call feature one can listen to all the activity in the area.  While this would be a great idea it really doesn’t work that way.

Close Call and ZIP Code scanning have some similarities but are really two different animals. Close Call (and the similar Whistler/GRE/RS feature called Spectrum Sweeper or Signal Search) is a near-field receiving option that scours the bands for strong signals and locks in on them. You can then see the frequency displayed. This is great but it has limitations.

The range Close Call works at depends on the strength of the signal, it has to be very strong to trigger. Portable radios usually have to be within a few hundred feet, mobile radios within a block and base stations or repeaters within a few blocks. Sometimes you can get stations further away but that depends on so many factors like antenna, frequency, elevation etc. that anything beyond those distances is considered luck.

Close Call is a great way to find new frequencies, especially at less documented sites like shopping malls and events. It is a great tool to find all those walkie-talkies used at locales and events but cannot be used as a replacement for proper scanner programming. One feature it lacks is the ability to look up a channel in the database or programming of the radio.

ZIP Code programming is recommended for those traveling thru an area if you don’t know what frequencies are being used there. Chances are the main channels are already documented on Radio Reference and thus should be in the internal database on your ZIP Code enabled radio. Uniden ZIP Code scanners also support the use of a GPS to automatically update the location as you move.

Be sure to use the right location service for your needs. Need to find new local (VERY local) channels? Use Close Call. Need to listen to specific services or systems in a particular area? Use the ZIP Code feature.

Monitoring Aviation with a scanner

Listening to aircraft and airports with a scanner can be fascinating for both the aviation enthusiast and casual listener. For plane spotters scanners are an invaluable tool to determine what aircraft will be where.

There are several types of monitoring and these can be broken down into several basic types:

  • Airport traffic and ground control
  • En route traffic control
  • Air to Air
  • Ground operations

These same 4 categories are used in both civilian and military aviation; they just use different frequencies.  Military tends to be a lot heavier on the Air-to-Air traffic than civilian aviation but otherwise they are remarkably similar in structure.

Let’s start out at the local airport. There are several types of airports out there that can be pretty well categorized into 2 types: “Controlled” and “Uncontrolled”. Some Uncontrolled airfields have a ground station, some have no radio facilities at all. Most Controlled airports have separate Tower and Ground control channels and busier airports may have several of each.

Controlled Airports

Controlled Airports have a control tower that is open at least part of the day. One or more Controllers are in charge of the movements on and around the airport, the distance of the controlled airspace depends on the local conditions and area. Any aircraft operating to or from or in the vicinity of the airport has to communicate with the Tower controller.

Controlled Airports usually also have a Ground Controller; he controls movements on the ground of aircraft and vehicles on the airfield. Smaller controlled airports sometimes combine the Air Traffic Controller with the Ground Controller but larger or busier airports have separate controllers. Air Traffic Controllers operate on the “Tower” channel and ground controllers operate on the “Ground” channel. If only one person is operating then the controller will often talk on both the Ground and Tower channel at the same time.

Very busy airports, like O’Hare, Atlanta, Phoenix, L.A. etc. may have multiple Air and Ground controllers for different sections of the airport. In Phoenix for example there are Air and Ground Controllers for the north side and different controllers for the south side of the airport.

Each controller has his own frequency assigned just for him. At a small controlled airport there may be a single Tower channel and a single Ground channel. Busy airports may have 3 or more of each.

Controlled airports also usually have an “ATIS” channel. ATIS stands for Automatic Terminal Information Service. ATIS systems transmit continually on a recorded loop and includes such information as local weather conditions, what runways are in use, any special information the pilots might need (like obstructions in the area of the airport etc.) and other important information. These are great to listen to when you first arrive at the airport to watch planes but since it continually transmits you will want to lock it out pretty quickly. The recorded messages are usually a minute or so in length and plays over and over again. When condition changes they will update the ATIS message. ATIS messages are assigned a letter and the next letter up is used when they change the message. After “Z” it goes back to “A”.

Other channels seen at larger Controlled Airports include “Clearance Delivery” (channels used to provide and verify flight plan instructions), “Ground Metering” (channels used to stage aircraft before they are released to move towards the runway for takeoff) and special channels used to coordinate things like fuel trucks, de-icing operations and others. Very busy airports like O’Hare and Atlanta may have dedicated ground channels for gate areas separate from the regular Ground Control channels.

Less busy controlled airports may only operate their control tower for specific parts of the day, usually something like 6:00 AM to 10:00 PM. After hours the “Tower” channel is used as a CTAF channel like as done at uncontrolled airports.

CTAF Channels / Uncontrolled Airports

Common Traffic Advisory Frequency (CTAF) is used at airports without operating control towers. This includes controlled airports when the tower is closed and airports with no control tower at all. The CTAF could be the tower channel (at a controlled airport after hours) or some other frequency, usually a Unicom channel.

Uncontrolled airports have no control tower so all operations are handled by the pilots themselves according to rules and conventions. The CTAF is used to coordinate actions on and around the airport. Usually the pilots will broadcast their intentions on the CTAF channel so other pilots will be aware and can act accordingly. You will hear a pilot say in the blind something like “Cessna N12345 inbound Mayberry 2 miles out for Runway 21, entering right pattern”. This means the Cessna airplane with registration N12345 is 2 miles away from the airport in Mayberry and plans to land on Runway 21 and will enter the airport’s pattern to the right of the runway.

Other aircraft, vehicles on the ground and plane enthusiasts will be able then to look out for a Cessna coming in. If a plane is already doing something that might conflict with out Cessna then he will either hold back and let the Cessna do his thing or let the Cessna know to watch out or even alter his plan to accommodate him. If an airport maintenance vehicle is out working he will be able to tell if a plane is on the way in and keep clear of him or even tell him to watch for him.

Other channels on the Aircraft bands

There are many other types of channels you might come across on the aircraft bands. Some of these are listed below. Some of the descriptions and uses seem to merge or conflict but all in all the whole system seems to work pretty well.

Unicom

Unicom is often misunderstood and confused with other terms like MultiCom and CTAF. Unicom is a radio station that is used to coordinate activities but it is not staffed by a controller. An airport might have a Unicom station staffed by an airport employee or a business on the airport. There might not be someone monitoring the Unicom station at all. The Unicom channel is usually used to coordinate activities such as fuel and tie-downs, requesting ground transportation and other activities. At uncontrolled airports that have a Unicom channel assigned it is often used for pilot reports and coordination but this is more of a Multicom type operation being done on a Unicom channel.

Most controlled airports also have one or more Unicom channels assigned, often 122.950. Pilots can use the Unicom channel to contact service businesses to arrange for fuel, cars, passenger service, tie-downs and other needs.

Multicom

Multicom is similar to Unicom but there is no ground station involved. The only radios used are those in the aircraft and occasionally ground vehicles. Most air traffic operations at uncontrolled airports are actually a Multicom operation being done on a Unicom channel.

Air-to-Air channels

Air-to-Air channels con be fascinating to listen to. The most infamous is 123.450. This is often used for informal chit-chat amongst pilots. Here in the USA it is common to hear pilots exchanging pleasantries or complaining about the weather. Often a group of private aircraft travelling together might use it to coordinate flight speeds and directions.

Over the oceans, in particular the North Atlantic between the USA and UK, airliners are supposed to monitor 123.450 since they are often out of range of traffic control centers.

There are many other air-to-air channels assigned for specific uses, including Search & Rescue (SAR), Balloon operations, and training. In the Phoenix area where there are many large flight schools there are training areas with specific channels assigned to them in a similar fashion to a MultiCom/Unicom channel to coordinate activities there.

Emergency Channels

There are several channels specifically assigned for emergency use. 121.500 is the most well known. Often called “Guard” (since you are supposed to stand guard on the channel) it is the channel that one would switch to in emergencies or if no other channel exists for an important communication. 243.000 is the military equivalent.

121.500 used to be used also for ELT’s (Emergency Landing Transmitter), these are devices that transmit a specific set of beeps when a crash or hard landing is detected. Most of these have moved off to new channels but occasionally one may pop up here and there.

Ground Operations

Many airports have some sort of facilities for fuel, repairs, tie-down etc. These will often use the local Unicom channel to allow pilots to arrange these services. At controlled airports 122.950 is commonly assigned as a Unicom channel for these purposes. Some airports might have alternate Unicom channels for different FBO’s (Fixed Base Operators). Bill’s Aircraft Fuel Company may operate on one channel and Toms Flying Gas might operate on another.

Pilots can be heard calling an airport’s Unicom operator while en route to the airport to arrange a fuel truck, ride for the passengers, or to find out where they want him to park the aircraft.

At uncontrolled airports the CTAF channel is usually the same as the Unicom channel. Pilots can be heard giving position reports, coordinating operations, getting weather reports or saying hi to his buddy.

Controlled Airports usually have more ground operations and associated radio traffic. Besides the Ground controller (who controls all aircraft and vehicular movements from the gates to the runway) and Air Traffic Controller (who handles all the aircraft in the airport’s airspace as well as on the runways) there may be Gate Controllers, De-Icing operations, fuel trucks, and others operating on aviation channels. On regular Land Mobile (business and public safety) frequencies may be all kinds of operations like baggage smashers, porters, aircraft tugs, personnel transportation, security, police, fire and EMS and more. Even the newsstand in the terminal may use radios to allow the clerks to chat.

Ground Control is a fascinating system to listen to. The Ground Controller usually works in the control tower, often on the level above the air traffic controller. He is responsible for any movements on the airfield except on the runway. This includes aircraft and vehicles. The guy out cutting the grass next to the taxiway? He has to get permission from the ground controller to be there and be able to communicate by radio. Same with the guy changing the light bulbs alongside the runway and the fuel truck that has to get from one side of the airport to the other.

The Ground Controller works closely with the Air Traffic Controller so that one doesn’t have an aircraft crossing the other’s area. For example, if a plane needs to cross the active runway while taxiing from one place to another the Ground Controller will coordinate with the Air Traffic Controller to get permission to do that. When a plane has landed and leaves the runway the Air Traffic Controller will tell him to contact the ground controller in order to taxi over to the gate.

Small controlled airports might have a single controller working both Ground and Tower at the same time during slow periods. Large airports might have 3 or more Tower controllers and a like number of Ground controllers working different sections of the airport.

En Route Air Traffic Control

The USA and Canada has several Air Route Traffic Control Centers (“Centers”) scattered about the continent. Each of these Centers are responsible for aircraft movements above a certain altitude for cross country traffic. Small planes that are flying VFR (Visual Flight Rules) under a specific altitude do not normally communicate with Centers but IFR (Instrument Flight Rules) flights and commercial traffic do.

“Centers” are responsible for tracking and controlling aircraft outside of airports and Terminal Areas. Each Center (there are over 20 in the USA) has a specific area to control and all aircraft above a certain elevation must be in contact with the Center. When an aircraft moves from one center to another he is “handed off” and assigned to a new channel. Each center has assigned channels and many remote base station transceivers to allow him to talk to any aircraft in his area, which might stretch for hundreds of miles. Each Center has many channels assigned to it. Center boundaries do not follow state lines, they are set up for the more efficient handling of traffic. Albuquerque Center for example covers most of Arizona and New Mexico as well as parts of Texas.

Operating in somewhat of a similar function as the Centers are TRACONS, or Terminal Control centers. TRACONS are responsible for aircraft going into or out of a major airport and handle it between the Control Tower and Center Controller. They also have specific frequencies assigned to them. They handle “Approach” (inbound to the airport) and “Departure” (leaving the airport) traffic.

An airplane travelling between Chicago O’Hare and Phoenix might start with the Gate controller at O’Hare International Airport, then talk to the Ground Controller there, then to O’Hare Tower. After takeoff he then gets sent to O’Hare Departure at the TRACON, who then hands him off to Chicago Center. Chicago Center hands him off to Kansas City Center, then they send him to Albuquerque Center who hands him off to Phoenix Approach. At a certain point he is then assigned to the Tower controller at the Phoenix Airport and after he lands switches to the Ground Controller there and perhaps finally to the Gate Controller. Each of these controllers have separate frequencies, so the pilot might be changing frequencies 10 or more times.

Larger aircraft usually have the ability to monitor 2 or more channels at the same time and pilots usually have the frequencies they need ahead of time so it is a lot more organized than it may seem.

Flight Service Stations

Flight Service Stations (FSS) provide weather and condition updates, including from other pilots and handle flight plans both on the radio and by other means (phone etc.). There used to be a system called Flight Watch on 122.000 nationwide but these have been combined with FSS services.  If you hear a pilot talking to “Radio” then he is talking to an FSS station.

Air-to-Air traffic

Probably the most interesting thing to listen to for plane enthusiasts is Air-to-Air traffic. This is radio traffic from one aircraft to another. Some of this traffic is chit-chat among pilots and occasionally is more like CB radio than professional communications. 123.450 is a common frequency for this type of chit-chat. There are other channels (sanctioned and otherwise) used for Air-to-Air traffic.

In August each year, before, during and after the huge Oshkosh EAA fly-in there are often many groups of aircraft that fly together to the show. They will invariably find a channel to communicate to each other on.

Some more official communications include channels assigned to Search & Rescue (SAR), firefighting, helicopter coordination, and pilot training.

Most large cities have a local helicopter channel where choppers from local police, news and tourism can coordinate activities. At large events where there are several helicopters present they may arrange a rotation or specific elevations so everyone gets the shots they want safely. I have heard a few times where one helicopter will assume an informal control operation and coordinate entry, exit and rotation for the several news choppers covering a big incident. While competitors, these are professionals and they depend on each other to do their jobs safely. 123.025 is the helicopter channel in many metro areas.

SAR and firefighting operations often involve multiple aircraft. If there is a ground station controlling the activity (such as the Command Post) they communicate with them to arrange entry and exit to the affected area, water drops and where certain aircraft are going to operate. Without a ground control or command post they work these items out among themselves on an Air-to-Air frequency.

In certain areas pilot training boxes are designated and frequencies assigned. An instructor in one aircraft may communicate with the student pilot to perform maneuvers and critique them.

Arinc

Aeronautical Radio Inc., commonly referred to as Arinc, is a provider of various communications services for the airline industry all over the world.  They provide communications services for airlines both en route and at airports.

Navigational Beacons

There is a huge network of navigational beacons around the continent called VOR’s (VHF Omnidirectional Range). There are about a thousand in the USA alone. They transmit continuous low-power signals on 108 thru 118 MHz. and provide pilots with bearing and distance. A pilot can set up on a beacon and use it to guide his aircraft. While this process is being taken over by GPS more and more there are still many VOR stations scattered around the country. The often look like big white traffic cones out in the middle of a field, in areas where suburban sprawl has occurred the VOR might be mounted on a large round platform 30-50 feet above the ground.

Some VOR’s transmit a Morse Code identifier and others transmit recorded or vice-generated weather information.

Military Air operations

While most civilian aircraft operate in the 118-138 MHz. band the military has a separate aviation band from 225 thru 380 MHz. Much of the traffic is pretty similar to its civilian counterparts. Many military air bases have control tower and ground channels and local support facilities, just like civilian airports. Centers and TRACONS have radios with military channels in them. Some civilian airports that host military units or receive military aircraft also have military channels for Tower and Ground operations. Most military bases also have civilian frequency assignments at them for the occasional civilian aircraft that may have to go there or fly in the area. Often the towers or controllers simulcast on both channels at the same time so that military users will know what other aircraft are doing and vice versa. Military tower controllers often talk to civilian aircraft in the area to coordinate flights and clear traffic thru Military Operating Areas or other restricted locales.

What really separates military aviation monitoring apart from civilian is the Air-to-Air traffic. The various branches of the military have Military Operating Areas (MOA’s) spread about the country and offshore waters. These MOA’s are used to practice maneuvers, dog-fighting tactics, formations and other activities. Out west in Arizona and California there are huge bombing ranges and areas for live-fire operations. All these activities operate on the MilAir band and provide fascinating listening. With a huge swath of spectrum (155 MHz.) to play with finding these operations is a hobby unto itself. Some dedicated MilAir listeners dedicate a dozen or more scanners to search out this huge range of channels looking for new activity.

MilAir operations often use a new frequency all the time, rotate thru a couple dozen channels or just grab random frequencies. The operations are often very short and varied so it is difficult to find sometimes, this adds to the fun! While military ground and air traffic control channels usually remain constant the air-to-air and range traffic varies considerably. Some very busy areas (like the Goldwater Range in Arizona) host aircraft from multiple bases and even several military branches and air forces from other nations. They may have established Entry and Exit frequencies to coordinate aircraft going to and from the range and assign routes.

Certain military aircraft will have both civil and military radios, these include units based at or operating at civilian airports or shared facilities. Most large transport and executive aircraft will have both UNH and VHF radios. Smaller military aircraft, especially fighters, may not have civilian radios so are limited to operations at bases and civilian facilities with military channels available.

Callsigns

Every aircraft and station uses some sort of callsign on the radio. Ground stations (Tower, Ground Control Center etc.) usually identify with the airport name or city (“O’Hare Tower”, “Phoenix Ground”, “L.A. Center”, “Cleveland Approach” etc.) while aircraft identify with a variety of methods. General Aviation aircraft usually identify with the registration number, usually with the full number (“Cessna N123AB”) on the first transmission to a new target and with an abbreviated call afterwards (“Cessna 3AB”). Aircraft with some sort of flight number identify with the airline or company name or call sign and flight number. The callsign does not always reflect the name of the company, it may be an historical name or derivative chosen for a multitude of reasons. The callsign “Cactus” for instance was used by US Airways before its merger with American. Cactus had been the callsign for America West and retained when they merged with US Airways. Callsign names may be found on the internet at various sources.

It isn’t just large airlines that use tactical callsigns. Task-specific flights often do too. Skydiving flights often use some sort of callsign like “Jump Ship” or “Skydive”. Medical flights often use “Mercy” to identify as such.

How do I find aviation frequencies?

The best place for aviation channels is the internet of course. There are dozens of sites dedicated to aviation monitoring and plane spotting.

The official data is available at the FCC’s website. You can download almost any information you want there, including airport charts, terminal procedures and more and it is all the official information. They even have charts for military facilities.

Another great resource is RadioReference.com. Between the database and the forums chances are someone has the information you want there. There are also Yahoo Lists, Facebook and other forums and mailing lists dedicated to various facets of aviation monitoring.

The civilian Aircraft band is basically between 108 MHz. and 138 MHz. 108-118 MHz. is mostly beacons and VOR’s along with AWOS stations, there is no two-way traffic there. Air Traffic Control and other two-way operations are on 118-138 MHz.

The Military Band is between 225 and 380 MHz. It used to stretch up to 406 MHz. but the 380-406 MHz. range has been reallocated mostly to other military uses like base operations. There is also some military aviation use of 138-144 MHz. and 148 to 150 MHz.

What scanner do I need?

This is the easy part! All current scanners these days handle the civilian aircraft band; no special upgrades are needed. Most newer scanners also work on the military bands as well. There are however scanners that are better for the Aviation enthusiast.

The BC125AT is ideal for aviation monitoring due to its small size and Service Search features. It is small enough to fit in your shirt pocket and has easy to use Service Searches for both the Civil aircraft band and the Military Aircraft band.

Consolidated Frequency List:

Here is a listing of some of the most common aviation frequencies in use. It is no means complete, be sure to check for local frequencies at www.radioreference.com and other sources.

  • 108-118           Navigational Channels (VOR, Beacons and AWOS)
  • 118-121           Air Traffic Control
  • 121-122           Mostly ground control
  • 122-128           Air Traffic Control
  • 128-138           Company/AirInc use

Here are some interesting discrete frequencies used throughout the country:

  • 121.500           Emergency “Guard” channel
  • 122.000           Flight Watch
  • 122.700           Unicom
  • 122.725           Unicom
  • 122.750           Air to Air
  • 122.800           Unicom
  • 122.850           Multicom
  • 122.900           Multicom
  • 122.925           Multicom
  • 122.950           Unicom           (Controlled Airports)
  • 122.975           Unicom
  • 123.000           Unicom
  • 123.025           Helicopters
  • 123.050           Unicom
  • 123.075           Unicom
  • 123.100           Search & Rescue (SAR)
  • 123.450           Air to Air (chat)
  • 243.000           Military Emergency/”Guard”

How often should you update your scanner programming?

One of the questions we get here at Scanner Master is how often one should update the programming on their scanner. The answer to that depends on a few things, including what kind of scanner you have, the resources available to you (computer, software etc.) and what is happening in your area.

The type of scanner you have is the first question we always ask. ZIP Code type scanners, such as the HomePatrol, x36/SDS type or the Whistler TRX and WS types are pretty easy to update with the free Sentinel or EZ-Scan software. With a Windows computer these can be updated as often as you like at no charge just by running the software and sending the updated data to the radio. Remember that updating the database does not update the Favorites Lists that you may have so if you are using Favorites Lists check them for any changes.

If you do not have a Windows computer or do not want to do this you can always let Scanner Master do the work for you. We sell fully programmed and ready to go SD Cards for your Uniden or Whistler ZIP Code enabled scanner for just $59.95.

On other modern scanners, such as the various Uniden, Whistler, GRE and Radio Shack digital radios (and some analog ones) they can be programmed by computer with the appropriate software and cables. If you have access to programming software then you can update these easily whenever needed. Scanner Master sells programming software for almost all the current scanners and most older ones.  – Read more

The third question relates to whether you actually need to change it or not. There are some places using the same channels they have for 20 years or more, the Chicago Police Department for example is using the same radio channels they were in the 1970’s for the most part. Other areas have changed frequencies or systems several times over the last couple decades.

For ZIP Code scanners we normally suggest that you update the database when you buy the radio and perhaps once or twice a year after that. If you go on a trip and are bringing your ZIP Code scanner with you update the database before you leave. You might have to update the scanner if you know that your targets have changed systems or perhaps they disappeared and you no longer hear them on the channels that once used.

For non-ZIP Code type scanners it is a little more difficult. Since these are pretty much custom programmed for your area you might have to tweak them from time to time to add a new channel or agency. If your targets move to a new system then you would need to reprogram or replace the scanner, depending on whether the scanner is capable of monitoring the new system.

We also suggest that you monitor the forums for your area at Radioreference.com. When things change they are usually discussed there, often in great detail.

As always, Scanner Master will be happy to help you reprogram your scanner, either with a replacement SD Card or by using our main-in programming service.

SDS100 Hints, Tips and FAQ’s

Here are a Baker’s Dozen of hints and tips to make life with your new SDS100 scanner happier. If your question is not answered let us know and maybe we can add it to Part 2!

1)         What is the deal with the battery?

Uniden designed the radio with a new Lithium Polymer battery pack, getting away from using common AA cells. While a lot of people preferred the AA cells since they can be easily obtained and swapped out, they just could not provide enough current to run the radio for a decent amount of time. The Lithium Polymer pack that comes with the radio was supposed to be sufficient but Uniden was not happy with the results so they designed a larger pack to be used. Unfortunately the radio was already on the assembly line by the time it was discovered that the battery life was not up to snuff.

Uniden decided to allow the radio to be sold and distributed as it was but included a notice in the box to advise purchasers to sign up for a FREE larger battery pack once they are available, likely in August 2018. Sign up at Uniden’s website and they will send you the new larger battery as well as a replacement battery door at no cost.

Once these batteries are available there should also be available for sale extra batteries. Eventually some sort of external charging device will also be available so you can charge one battery while using another.

2)         Can I charge the battery and run the radio at the same time?

Actually, on the SDS100 you can! While other Uniden scanners do not support this, as long as your charger has sufficient current capability you can charge the battery with the radio on as long as you have that option turned on in the Settings>Battery Options>Set Charge While On menu.

Why would you not want this option turned on? The only reason I see is that the red or green charge light will be on all the time when the radio is plugged in. It might take a while longer to charge the battery when the radio is on but it should not be a big issue.

3)         What else can I use to charge the battery?

The SDS100 comes with a USB charger. Alternately any USB charger will power and/or charge the SDS100 battery. If you have a smartphone or other USB device charger you can use it if you don’t want to use the charger that came with the radio.

In the car you can use any USB port to power/charge the radio. Most cars these days will have a USB port to charge your phones and other devices, these work well with USB powered scanners like the SDS100.

4)         What is the deal with the raised ridge by the antenna connector?

That ridge is part of the water proofing of the radio. When used with the supplied rubber duck antenna this helps provide a seal to block water from getting into the radio. The supplied SDS10 antenna has a rubber gasket that fits this ridge.

This does however block use of many third-party antennas and adapters. The SDS100 comes with an SMA-BNC adapter so you can use your BNC antennas but with this adapter you will not have the water resistance provided with the supplied antenna.

5)         What is that little hole on the back of the radio? Am I missing a screw?

That hole below the belt clip knob is there to provide a case breather to prevent pressure issues. The radio is still water resistant due to other parts inside the case. On some radios there have been issues with elevation changes causing the case to pressurize and damaging components. This pressure relief helps to prevent these issues.

6)         It is hard to see the color screen in sunlight, what can I do?

The SDS100 color screen is a thing of beauty but can be difficult to read in direct sun. If you go into display settings you can select white on black or black on white instead.

7)         What are the “Detail” and “Simple” screen modes?

The SDS100 has a fully customizable display. You can set it up to display just the basic information (Simple) or all kinds of special information (Detail) when receiving. Almost every item can be positioned where YOU want to put it. You can even select the colors each item is displayed in.

Simple Mode shows just basic information in an uncluttered way. Detail Mode allows you to show many different details about what you are listening to, such as trunking ID’s, PL tones etc. so you can analyze systems you are listening to. You can switch between these at will and change the way they look on the radio via the keypad or Sentinel.

8)         What are the software options?

The SDS100 uses the free Sentinel software to do the database and firmware updates. This is the same version as used on the BCD436HP and BCD536HP scanners and you can share files back and forth among all 3 radios. There is a separate version of Sentinel used for the HomePatrol models. The HomePatrol modes Sentinel has a brown icon, the 436/536/SDS version uses a green icon. Sentinel can also be used for programming Favorites lists as well.

ARC536 by Butel can be used to also program Favorites Lists, it provides the familiar Butel interface so if you have used other ARC products you will feel right at home. The Pro version also supports Virtual Control as well as other features.

9)         Will there be a base/mobile version of the SDS100?

Yes! The SDS200 is identical in operation and programming to the SDS200, but in a mobile package with a larger display.

10)       How does the GPS unit connect to the SDS100?

The Uniden BC-GPSK GPS receiver works on many different Uniden scanners and comes with several cables to adapt it to these scanners. With the SDS100 (as well as the BCD325P2) however you need a different cable. This special adapter cable, available at scannermaster.com, replaces everything but the GPS disk and attached cable. Plug the round plug from the GPS into this cable, the USB plug into a USB power source and the small plug into the Charge/USB jack on the radio. The radio will be powered/charged from the GPS cable as will the GPS itself.

11)       Sharing Favorites Lists with other scanners

The SDS100 can share the same Favorites Lists as the BCD436HP and BCG536HP, and since they all use the same version of Sentinel, it is really easy to share. You can create different Profiles for each scanner if you want or just program them all the same.

To share files from other radios you would need third party software and import/export those files with that software.

12)       If I have many Talkgroups or Sites in my trunked system will it slow down the scanner?

If you have many TALKGROUPS then no, it will not slow the scanner down. The SDS100 (and other Uniden scanners) does not actually scan talkgroups, it scans SITES and if it sees an active Talkgroup it looks to see if it is in an active Favorites list and Department. If it is it displays the name and listens to the talkgroup. If not it ignores it and moves on. All this is done in fractions of a millisecond.

If you have that trunked system’s Favorites List set to Trunked Search the scanner will look for the talkgroup and see if it is listed. If it is in the radio it will show the name etc. and hear the traffic. If it is not already programmed into the radio it will display it as “Unknown” with the Talkgroup number. If you can identify the user you can add it to your Favorites List.

What can slow down your scanner is if you have a lot of SITES programmed into the radio that you have no chance of hearing. If your area uses a large regional or statewide system then either turn off or delete the sites you would not be able to hear. (The radio’s manual describes how to do this…). The fewer sites the radio has to go thru the faster it will get to them.

13)       Do I need ProVoice, DMR or NXDN?

Well, maybe, maybe not… Check the RadioReference database and see if anything in that area use these modes. If they use them in the areas you want to listen to then you might want to get the upgrades. ProVoice is used mostly by public safety agencies in specific areas including Oklahoma City, San Antonio, Denver and Albuquerque.

DMR and NXDN are mostly used by business operations and campus installations but are occasionally used by smaller police and fire departments as it is less expensive than P25 digital systems.

14) Where can I go for more information?

https://wiki.radioreference.com/index.php/SDS100_and_SDS200_FAQ_Page has a ton of info on the SDS100 and SDS200

The SDS-100 and why it is so revolutionary

If you haven’t heard already, the new Uniden SDS-100 handheld digital scanner has taken the prize as the most desired scanner available. Introduced in the spring of 2018 and finally available in June, we sold every one we had and were promised and just now are able to keep them in stock for regular purchases.

What makes the SDS-100 so special? Why does it work so well? Why is it worth all the extra money it costs? Glad you asked!

The biggest advantage to the SDS-100 has over other scanners is it’s ability to monitor Linear Simulcast Modulation (LSM, also known as P25 Simulcast) systems. Traditional scanners do not work very well often with LSM systems but the SDS-100 handles them much better, almost as well as a regular system radio like the police use. Other scanners tend to break up, miss words or phrases or just not hear it al all.

Why, you might ask, does this happen? Simply put, a simulcast system transmits the same traffic on the same frequencies at the same time from 2 or more locations. A simulcast system would transmit from multiple sites to provide better coverage within its intended operational area. These signals then tend to arrive at your scanner with slightly different time delays. Even though these time differences are almost indescribably small, the fact that they are digital1’s and 0’s makes them interfere with each other. The 1’s from one tower tend to block the 0’s from another tower. This causes interference and sometimes the interference is so bad as to block the entire conversation.

The SDS-100 uses a totally different internal architecture than other scanners, basically using a Software Defined Radio (SDR) with True-IQ processing to more properly decode LSM transmissions. This means that the SDS-100 will receive these simulcast systems with little to no distortion or interference.

There are other advantages to the SDS-100 SDR-based architecture. It allows other features and capabilities to be added down the road. While Uniden has not announced any of these features yet the possibilities are endless.

The SDS-100 works much like the BCD436/536 series scanners, the interface is very similar and they use an updated version of the Sentinel software so you can share your Favorites Lists between them.

The other big feature with the SDS-100 is the color display. This display can be used in either a “Simple” or “Detail” mode. The Detail mode is entirely customizable. You can place any of dozens of different fields almost anywhere on the screen and assign any color to just about any item. You can switch back to Simple mode and just have the basics, still in color or even switch to a simpler black and white scheme that works better in bright sunlight.

The SDS-100 is an amazing radio. If you have simulcast systems in your area then it works much better than other scanners. While it is more expensive than other scanners it is well worth it!

Why does my Phase 1 scanner still work on a Phase 2 system?

So you have had your trusty old BCD396XT or other Phase 1 scanner for years and it works great. You hear that your system has upgraded to a Phase 2 system but your old Phase 1 scanner still works? What gives?

Here is the skinny on that: Most “Phase 2” systems are actually operating in Phase 1 mode, at least partially. When a system upgrades to Phase 2 not only does the infrastructure have to be upgraded (base station repeaters, controllers etc.) but also all of the mobile and portable radios. Until ALL radios have been upgraded and reprogrammed the system will usually be operating in Phase 1 mode.

Many systems listed in the RadioReference database as “Phase 2” have been heard with Phase 2 operations but still operate as Phase 1, so in reality it is better termed as “Phase 2 Capable”.

Some wide area systems may operate in Phase 2 modes in one area and Phase 1 elsewhere. The huge StarCom21 system in Illinois is a good example of this. In the Chicago area some users use Phase 2 but others are on Phase 1 since the new radios are expensive. Until all those older radios are replaced or reprogrammed the system will operate in a mixed Phase 1 or 2 mode.

This makes your older Phase 1 only scanner usable for at least parts of the system and saves you from having to replace it right away. When they do switch entirely over to Phase 2 then you will need to replace your scanner.

Another question we often get here at the ScannerMaster International Headquarters is how one updates his older Phase 1 scanner to Phase 2. The answer to that is that you don’t. There is no update path for older scanners to Phase 2; you will have to replace it.

Most newer model digital scanners from Whistler and Uniden handle Phase 2, see them at https://www.scannermaster.com/Digital_P25_Phase_II_Scanners_s/708.htm

Signal Strength – It is all relative

So what does Signal Strength really mean? Most scanners these days have a Signal Strength indicator, usually with up to 4 or 5 bars to indicate a strong signal. How are these calibrated? Is 4 bars twice as good as 2? Do I need a full-scale signal to hear my local action?

To answer these questions let’s look at how the scanner comes up with the signal strength indications. Basically it is a representation of the RELATIVE strength of a given signal. The radio reads the voltage present within its circuitry when a strong signal would provide a higher voltage and translates that to the number of bars displayed. A weaker signal would be expected to produce a lower voltage and thus fewer bars.

The big thing to remember is that these meters are not calibrated so they are nothing more than a pretty good ideal if whether a signal is strong or weak. It does not mean that a certain indication (let’s say 3 bars) means a specific signal level. While one can expect that 4 bars is better than 3 (and it usually is) that doesn’t mean that the signal is 33% stronger.

What the signal strength indicates (it doesn’t measure…) is the strength of the signal at the antenna jack. It does not indicate voice quality. One can have a signal that indicates 4 or 5 bars but with a lousy voice quality and hear very little. Conversely an indicated signal strength of just one bar could still present an excellent quality voice signal.

What is also important in using the signal strength indication is the noise floor. Noise Floor is the level of noise present when nothing else is detected. The noise floor is usually higher in city environments than rural ones due to the higher level of electronic equipment generating signals. This includes computers, Wi-Fi, broadcast stations and other transmitters etc. The noise floor is usually higher in homes than fields due to the same issues. Certain specific locations tend to have much higher noise floors than others. Gas stations are notorious for RF noise generated by gas pumps for some reason. Paging transmitters tend to be noisy as well.

So what then does the noise floor have to do with how many bars I get on my scanner? Well, with a high noise floor you have to have the squelch set higher to block the ambient signals. Some places might have a noise floor that generates 2 or 3 bars, that means anything you want to hear has to be stronger than that.

The signal strength indicator also responds to preamps and antenna issues. While a preamp increases signal strength it also increases the noise floor. Connect a better antenna and you should expect more bars. Be careful that you don’t overload the scanner, too much signal will cause more problems than a poor signal will.

Preamps work best in more rural areas that have a low noise floor but will overload scanners on strong signals, especially in high RF areas like cities.

One more note: You will often see a signal strength indication on a trunked system even when it is scanning without stopping. The indicated signal strength is that of the control data channel.