Conventional | Scanner Master Blog

One of the best sources for scanner information available is the RadioReference.com database. This is a huge listing of frequencies used thruout the USA and Canada for all types of two-way radio operations.

If you do your own scanner programming then the RRDB is invaluable for information. It is usually more accurate than the agencies themselves have! Even if you only use a database scanner (like a HomePatrol or TRX) then it helps to understand the database so you will have a better idea of what you are listening to. Remember: The data in your scanner came from RadioReference in the first place.

To read the RadioReference database and understand how it works you need to understand how it works. Without understanding how it is laid out it can be daunting, there is a whole lot of information at your fingertips.

To understand it you need to know a couple things. There are two main types of data available, trunked and conventional.

First we will look at a conventional frequency listing. Then we will look at trunking information. (Conventional means that it is not trunked.)

Here is the frequency page for Lee County Florida. It shows several fields:

Frequency (Actual frequency used or the repeater output)
Input (Repeater inputs)
License FCC Callsign, click on this to see what frequencies and other info is available for it.
Type Base, Repeater, Mobile only etc.
Tone Could be PL, DPL or NAC 9for P25) etc.
Alpha Tag A short tag used on some scanners, akin to channel numbers etc.
Description A longer description of the channel and its use.
Mode FM, AM, Digital etc.
Tag The classification that the channel falls under.

If you hover over the column title it will tell you what the codes mean.

Since so many areas use trunking systems these days one might miss a lot of the info needed to monitor the area. Look at the bottom of the county’s page to see a list of trunking systems active in the county. If you see one that appears to be used there click on it to see the data. The first part you will see it the basic info:

At the top you will see an info box with the system name, location, type and other info. Below that you will see the System ID’s (some scanners will show the System ID to identify it) and other info.

If you scroll down the page next you will see the trunked system Sites. Sites is where you will find the actual frequencies used by the system. Some systems only have 1 or 2 Sites, others (like the one shown) have dozens.

This is a portion of the Site List for the huge Illinois StarCom21 system that has many sites all over the state. There are several columns:

RFSS is the Zone number (RF Subsystem), then the Site Number within the Zone. Sometimes Sties are shown in other contexts as X-YYY (1-012 meaning Zone 1, Site 12) or just XYY (112).
Next is the Site Name, usually the city or location the site is located in. The county the site is in follows.
Last are the frequencies used at that Site. Some freqs will be shown in red, these are known to be “Primary” control channels (mostly for P25 systems). Other freqs will be in blue, these are known to be “Alternate” control channels. The rest are shown in black, these are not know to be used as control channels but are used for voice. Unless you know for sure otherwise, it is usually best to include all channels of the Site in your scanner.

The last part of the Trunked system information is the Talkgroup List. These are the virtual channels used to allow the correct people to communicate within the system.

The columns here are:

DEC (Decimal) The most common way to identify a talkgroup in scanners.
HEX (Hexidecimal) Another way to view Talkgroups, used mostly by the fleet radios.
Mode Tells you if it is Digital (D), Analog (A), Encrypted (E) or TDMA (T).
Alpha Tag The short channel name
Description More inclusive description of the channel and its use
Tag The classification (Service Type) for that talkgroup.

By understanding the way the data is laid out you can apply this to your programming and understanding of the systems you listen to.

Encryption is a four-letter word among scanner enthusiasts. Encryption is the act of scrambling a signal to make it unmonitorable to radios not equipped with the proper technology and (most importantly) the proper key. The encryption keys are code numbers that are set up to assure that only permitted radios may hear and participate in a communication.

There is no way to decrypt a modern encrypted communication with a scanner, even with any of the various updates. Contrary to the occasional belief, the “Extreme Update” etc. does not open encryption. Neither will any firmware updates.

The only way possible to hear an encrypted communication is with a properly programmed System Radio programmed with the encryption keys. Occasionally police departments with encrypted systems will provide a system radio with basic talkgroups to media, wreckers, neighboring agencies and others that might have a legitimate need to monitor them. Unfortunately this privilege does not extend to scanner users.

So now what do you do if your agency goes to encryption? Often the police will be the only ones to go encryption so you may still be able to listen to other agencies like Fire/EMS, Street and Utility departments and mutual aid channels, often on the same radio system as the encrypted agency. Often the old channels are still in use for other purposes, as backup, tactical, or car-to car use. Some agencies only have encryption on certain channels, for example Tac or Swat, while leaving Dispatch in the clear.

Your scanner may still be used for many other services that rarely use encryption and you may discover all new listening experiences. For example, railroads, aircraft and business operations may still be monitored. Try listening to these services for a while and you might get interested in them. They can be fascinating, even more so than police traffic.

There is also the (slight) possibility that the agency could remove or reduce the use of encryption. In these days of mistrust of the police, however unjustified, encryption can be seen as a block to transparency. Some agencies have since removed encryption from routine dispatch channels for this reason.

PS: Modern encryption is most common these days on P25 digital systems but can also be used on other digital systems. Older analog systems occasionally used rudimentary scrambling that could be cracked with decoder kits or even monitored by some people that could make it out audibly. Those systems are pretty much all gone these days and rarely encountered due to the ease of being overcome.

Just because the police are gone from your scanner doesn’t mean the scanner is totally useless.