800MHz Channel Plan

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AnalogDigital

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Does anybody have a link or links to a page or pages that show the 700MHz and 800MHz channels and the corresponding frequencies? Channels like these:
00-0000
02-1470
02-1520
Thank you
 

marksmith

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Those look like Talk group ID's for one type of trunked system that isn't as prevalent as a lot of others. They are not frequencies. Systems can program those channels to be whatever they want. There's no universal list.
 

GTR8000

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There is no standard/universal plan for those channels. Although many systems tend to stick with what could be considered a default band plan, not all do, and thus no official standard.

You must calculate the frequencies that correspond to the channel IDs by using the band plan of the system.

As an example, many (but not all) Motorola ASTRO 25 systems will use a common band plan of:

Bandplan #0: Base=851.00625 Spacing=6.25
Bandplan #1: Base=762.00625 Spacing=6.25
Bandplan #2: Base=851.01250 Spacing=12.5 TDMA
Bandplan #3: Base=762.00625 Spacing=12.5 TDMA


So using that band plan we can calculate the channels you've provided by doing a little arithmetic:

  • 00-0000 would translate to the base frequency of band plan 0, or 851.00625
  • 02-1470 would be a TDMA channel, and so the channel ID must be divided in half first, then multiplied by the spacing, with that result added to the base frequency. So 1470÷2 = 735, multiplied by 0.0125 equals 9.1875, added to the base frequency of 851.0125 gives you a result of 860.200 MHz
  • 02-1520 is calculated the same as 02-1470, and results in 860.5125 MHz
Also note that TDMA channels will have two channel IDs, one for each slot. Example 02-1470 and 02-1471, which both translate to the same frequency. When dividing those by 2, you need to round the higher channel down by 0.5 before multiplying. In other words 02-1471÷2=735.5, so you round down to 735 which is the same as 02-1470.

If the system in question is using a different band plan, which it very well might, then the resulting frequencies may be different than my examples. Hence "no standard plan".
 
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AnalogDigital

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No, those are the Channel Numbers. They are the Input Channel Numbers but that is what they are. I remember that there was a page or pages that showed the actual Channel Numbers for each 700MHz and 800MHz frequency. I just cannot remember what that page was or pages were. That is the way the Channel Numbers show up on pro96com.

Thanks GTR8000 That would make sense, base on what I am seeing using pro96com.
Would the Primary Control and Alternate Control frequencies also be divided into Slot 0 and Slot 1? What about the 00-0000 channel since it is being used as a Data Channel/Frequency.

Okay since each frequency is divided into two slots that must likely means that thwee are two conversations going on on each frequency. Is this correct? How does a scanner figure out which frequency slot to stop on?
 

GTR8000

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Control channels are always FDMA, not TDMA, so no slots on those. Only voice traffic is carried in TDMA slots. Yes, two conversations per frequency on those TDMA voice channels. The scanner knows how to decode each slot by making the same band plan calculations I detailed. Also, those are not input channel IDs, but the repeater outputs for the trunked system. Oh and seeing channel "0" used is very rare, but I suppose not impossible.
 

AnalogDigital

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Why is Channel 0 rare? Could it have something to do with the fact that I am just on the edge of the system and the control channel does not show up as a solid decode (green) but intermittent? Will the data channels always be FDMA also. There is a Channel that shows up as 00-0000. It is indicated a d for Data.
 
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