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Common Trunking Programming Questions


General Trunking Questions

  • ''What is this rebanding I keep seeing mentioned?''
    • The answer to this is pretty involved, see the excellent special topic Rebanding article.
  • ''I am trying to monitor a trunked system in my area. I have a (insert model) and all I hear is noise. What's wrong?''
    • You may be listening to the data on the Control channel as audio. The system must be programmed as a trunked system. Your scanner must support trunked system monitoring. See this category page to see the scanners that can monitor trunked systems.
    • The system may be transmitting digitally-encoded audio.. Check the database for your area to be certain. The only scanners on the market that can receive non-encrypted digitally-encoded audio are those listed on this category page.
    • Another possibility is that you are hearing leakage from your cable system. See our CATV Interference article for possible remedies


Interpreting Database Trunking Entries

On the Radio Reference Database, there are some terms used that may be unfamiliar to the new scanner user and some data that you don’t need. Most of the time, if you mouse over the column heading in the database, you will get the answer to your question. If this doesn't work, please see our Glossary article.

  • ''On the trunking talk group display, I see DEC and HEX, which one do I use?''
    • For Motorola and Project 25 (APCO-25) systems, all trunk tracking scanners accept what is known as the Uniden Decimal format, that is the DEC number you see in the Talkgroup display. The HEX number is the actual Motorola Talk Group equivalent of that number as a hexadecimal. Professional radios (such as Motorola handhelds) and the newer GRE PSR-500 and PSR-600 scanners can use them (as can the Uniden XT series), but other scanners can't. There is a correlation between the two, but this correlation is different depending on the system being looked at. Some systems use a different format all together such as the LTR systems (system-home repeater-talk group) x-xx-xxx format or the EDACS AFS (Agency – Fleet – Sub-fleet)
  • ''On the trunking talk group display, what does the mode mean?''
    • Each talk group in a trunking radio system may broadcast in many modes, the mode most often found for a particular talk group is displayed in this column. If you mouse over the column heading you will see the various codes used in the column and what they mean.
  • ''On the trunking system I am trying to program, some of the frequencies listed are red or blue and have an asterisk next to them, what does that mean?''
  • ''On the trunking system I am trying to program, some of the frequencies listed have a (c) or (a). What does this mean?''
    • The red and blue frequencies are those identified as the control channel (CCh (in red with a '(c)') or alternates (in blue with an '(a)').
    • Now comes the confusion, if the system you are looking at is a Motorola or a Project-25 system and your scanner is capable of Control Channel Only trunk tracking, you only need to program the control channels.
    • If you are programming an EDACS or LTR system, then you must use all of the frequencies listed and put them in the correct order and in the correct position in your scanner. Some scanners ask for the LCN (Logical Channel Number) when programming these systems and others rely on you placing them in the correct bank position on your own.
      • If you look carefully at the frequency display you will see these types of systems have a small number to the left of the frequency, which is the LCN of that frequency. For example, if you were programming an EDACS system in bank 2 of a Pro-97 scanner, then you would put the frequency for LCN 1 in bank position 201, LCN 2 in position 202, and so on.
    • Note, in both EDACS and LTR systems, not all positions may be filled and there is no rule about skipping slots, so a site may start on LCN 4, which you program (again using the above example) in bank position 204, and go on from there. If you are told to start at bank position 1 in a bank, that is only correct if there is an LCN 1.
  • ''How do I tell if a system is to be programmed as a Project 25 system?''
    • Examine the system voice as listed in the database. Those entries that say System Voice: Analog and APCO-25 Common Air Interface are not true Project 25 systems, as they have one or more analog talkgroups. Program these systems as a Motorola system, and let the scanner detect the digital. If the System Voice says System Voice: APCO-25 Common Air Interface Exclusive then this system is a true Project 25 system. In both cases, a Digital Trunktracker is required to fully copy these systems, assuming none of the talkgroup entries are marked with 'E'. These are encrypted, and no scanner will copy them.
  • ''The database says that my area uses EDACS Provoice (or EDACS OpenSky ). Can any scanner receive these formats?''
    • Due to the proprietary nature of these formats, no scanner can receive either of these formats. There are several such formats which scanners cannot track (or receive); the most common ones are listed at the bottom of this page

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