American Electric Power (AEP) P25 WACN 92715

scannerboy02

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I apologize for not being able to go out and get a sample of what I'm hearing yet but thank you to @ralexander5 for getting it done!

We have a Presidential visit in Cincinnati today and he is going to a location less than a mile from my house so I have been scouting the area for RF monitoring and have a lot of my equipment now dedicated to the visit.

I will hopefully be able to go out and record a sample of what I'm hearing later this week or next.
 

scannerboy02

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In hopes of figuring out a way to monitor this new system type on a scanner I have been doing some testing with my SDS100 on my local P25 Phase II public safety system.

Being that the P25 standard doesn't use TDMA in conventional mode it appears the scanners will not decode P25 TDMA voice traffic in conventional mode, at least it's not working for me. So I programmed all of the system frequencies, including the control channel, as both a 'P25 X2-TDMA' system and a 'P25 One Frequency' system.

So far it doesn't appear to be receiving voice traffic as a 'P25 One Frequency' but it is receiving voice traffic as a 'P25 X2-TDMA' system, so this may be a way for us to at least hear the voice traffic on our scanners until the manufactures come up with support for TDMA control channels.
 

mtindor

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In hopes of figuring out a way to monitor this new system type on a scanner I have been doing some testing with my SDS100 on my local P25 Phase II public safety system.

Being that the P25 standard doesn't use TDMA in conventional mode it appears the scanners will not decode P25 TDMA voice traffic in conventional mode, at least it's not working for me. So I programmed all of the system frequencies, including the control channel, as both a 'P25 X2-TDMA' system and a 'P25 One Frequency' system.

So far it doesn't appear to be receiving voice traffic as a 'P25 One Frequency' but it is receiving voice traffic as a 'P25 X2-TDMA' system, so this may be a way for us to at least hear the voice traffic on our scanners until the manufactures come up with support for TDMA control channels.
I was wondering if that would work. Thanks for testing it.
 

mtindor

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In hopes of figuring out a way to monitor this new system type on a scanner I have been doing some testing with my SDS100 on my local P25 Phase II public safety system.

Being that the P25 standard doesn't use TDMA in conventional mode it appears the scanners will not decode P25 TDMA voice traffic in conventional mode, at least it's not working for me. So I programmed all of the system frequencies, including the control channel, as both a 'P25 X2-TDMA' system and a 'P25 One Frequency' system.

So far it doesn't appear to be receiving voice traffic as a 'P25 One Frequency' but it is receiving voice traffic as a 'P25 X2-TDMA' system, so this may be a way for us to at least hear the voice traffic on our scanners until the manufactures come up with support for TDMA control channels.
The more I think about it I removed my comment. I got confused. You're confusing me by posting about activity in your area from a different system, in the AEP thread :)

I'd think that if you are hearing any traffic, that it's FDMA traffic and not TDMA traffic. Not sure how the scanner would know what audio to produce with out guidance from a control channel regarding which timeslot the activity is on.

mike
 
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mtindor

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scannerboy02

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I'd think that if you are hearing any traffic, that it's FDMA traffic and not TDMA traffic. Not sure how the scanner would know what audio to produce with out guidance from a control channel regarding which timeslot the activity is on.

mike
The system I am testing 'P25 X2 TDMA' mode with is a Phase II system with voice traffic in TDMA mode. P25 X2 TDMA uses the old conventional Motorola X2 format to pull the voice traffic from each timeslot of each frequency. This is why my testing did NOT work in 'P25 One Frequency' mode, it was unable to detect the timeslots.

All you need to do is enter the frequencies for each site including the TDMA control channel, because the second slot on the TDMA control channel could be used for voice traffic.

I am posting this in the AEP thread because right now it's the ONLY way to monitor these TDMA control channel sites with a scanner.
 

mtindor

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The system I am testing 'P25 X2 TDMA' mode with is a Phase II system with voice traffic in TDMA mode. P25 X2 TDMA uses the old conventional Motorola X2 format to pull the voice traffic from each timeslot of each frequency. This is why my testing did NOT work in 'P25 One Frequency' mode, it was unable to detect the timeslots.

All you need to do is enter the frequencies for each site including the TDMA control channel, because the second slot on the TDMA control channel could be used for voice traffic.

I am posting this in the AEP thread because right now it's the ONLY way to monitor these TDMA control channel sites with a scanner.
Rgr that!
 

GTR8000

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The system I am testing 'P25 X2 TDMA' mode with is a Phase II system with voice traffic in TDMA mode. P25 X2 TDMA uses the old conventional Motorola X2 format to pull the voice traffic from each timeslot of each frequency. This is why my testing did NOT work in 'P25 One Frequency' mode, it was unable to detect the timeslots.
X2-TDMA was not a conventional protocol; it was Motorola's proprietary implementation of P25 TDMA trunking which pre-dated the official P25 Phase II TDMA standard. There is actually very little difference with regard to the control channel signaling between X2-TDMA and Phase II TDMA, the primary difference being differing IDEN_UP messages between the two protocols, with everything else following the P25 standard. It was the traffic channels that were different with an X2 system vs Phase I, and then of course Phase II came along, rendering X2 obsolete.

If you are able to decode the TDMA control channel and track the system with the scanner using X2-TDMA, then P25 Trunk (i.e. a standard P25 system) should work as well. One Frequency Trunk won't work because that scans the frequencies conventionally, and there is no time slot information available using that method.

Of course that assumes that you are dealing with TDMA control channels on the site(s) you are monitoring. Has that been confirmed yet?
 
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mtindor

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Should I submit TDMA sites that I know are on the air but can't decode and don't know the site numbers and alt CCs?
I just picked up the ticket, and sent you a mail via the ticket system. If the procedure you are using is the one I asked about in the ticket ( #1, #2, #3 steps in the ticket), then sure -- I think that's reasonable. We want as little guesswork as possible. And I think as long as that particular procedure is followed, it is safe to call it a TDMA CC site.

Mike
 

scannerboy02

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If you are able to decode the TDMA control channel and track the system with the scanner using X2-TDMA, then P25 Trunk (i.e. a standard P25 system) should work as well.
The X2 TDMA mode in the scanner ignores the control channel and just "scans" the entered frequencies for voice traffic. If you hold on a talk group it just flips through the entered frequencies looking for the TGID, and thus misses a good amount of traffic, from my recent testing.
 

nd5y

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When Hedley TX first came on the air it was FDMA. I copied it one time just enough to get the NAC and it was too weak to populate the neighbors. That's why it's already in the db. Now one of it's neighbors showed the control channel as using the TDMA band plan. I don't know when it changed.

Aspermont is probably the same way. One nieghbor shows it as TDMA but I haven't been able to copy it recently because there are too many other CCs on 854.8125.

Woodson TX and Mangum OK both started as FDMA then switched to TDMA. I already had complete info on them.

Munday TX has been TDMA since it switched to P25. It shows up on the neighboring sites as using the TDMA band plan.

Throckmorton TX has been TDMA since it switched to P25 but none of the sites to the north have it as a neighbor so I don't know what the site number is.
 

GTR8000

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The X2 TDMA mode in the scanner ignores the control channel and just "scans" the entered frequencies for voice traffic. If you hold on a talk group it just flips through the entered frequencies looking for the TGID, and thus misses a good amount of traffic, from my recent testing.
That's not true, it does not ignore the control channel. You can test this out by deleting the control channel frequency from the site, at which point it will not stop on any TDMA traffic channels for any activity.
 

mtindor

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Should I submit TDMA sites that I know are on the air but can't decode and don't know the site numbers and alt CCs?
Here is a process that I think would give the best result, barring the ability to capture audio for decoding. This is an example:

1. You tuned to a direct peer of Hedley with UT or DSDPlus, and it reported peer site 1F8-31.31 having a CC of ###.####

You know 1F*-31.31 was Hedley in the past

2. Then you tuned to ###.#### and it has a signal, sounds like simulcast, and you can't copy it one bit with UT/DSDPlus.

You already know the signs / sounds to look for

3. Thus ###.#### (reported as being the current CC for 1F8-31.31) is then deemed TDMA CC.

Personally, I think that is reasonable. A little bit of hoop-jumping, sure. But if one wants information as accurate as possible, hoop-jumping is often needed.

But if any of that relies on old peer data then it would not be good to do it. You want to use current peer data.

Mike
 

GTR8000

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The X2 TDMA mode in the scanner ignores the control channel and just "scans" the entered frequencies for voice traffic. If you hold on a talk group it just flips through the entered frequencies looking for the TGID, and thus misses a good amount of traffic, from my recent testing.
I just went back and re-read your previous posts, and realized that you are running this X2-TDMA "test" on your local P25 system, not any of the Duke Energy sites. So it has no relevance to TDMA control channel testing, and is simply scanning your local system just like it would any regular FDMA control channel system. Remove the active control channel from your list of frequencies, and it will no longer stop on traffic channels.

At this point what I'm gathering from your posts is that a) you're not even getting decent signal from the Duke sites at home, which could account for you not being able to decode anything and/or b) you may well be hearing P25 test patterns for coverage testing, not any sort of control channel (FDMA or TDMA) or voice/data traffic

I think at this point it's worth reminding that this is the AEP thread, not a Duke Energy thread, and it's probably best to refrain from further speculation about what Duke may or may not being doing in this thread. Save it for the P25 TDMA Control Channel decoding -- requesting help from experts thread that mtindor started.

EDIT: Or post in the Duke Energy thread. It seems from a quick glance at the last page of that thread that the system is not even online yet, and they are doing coverage testing? Are you just assuming or speculating that TDMA control channels are in use simply because you can't decode what may be P25 test patterns? :unsure:
 
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mtindor

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Tonight I can receive the 6 closest sites to the N and NW of me.
Here are their control channels and neighbor control channels.
View attachment 106972
View attachment 106973
@nd5y - in the wiki I changed things around (at least on 1F8 and 1F9) to add a "T" column next to the reported control channel to indicate TDMA CC, rather than having that field over on the right (where peers are listed) having the notation.

The only one I didn't touch was 1F8-40.40 Turkey - as the site had never been confirmed by personal monitoring (and thus is not in the DB) and it has the TDMA notation in the description and I was not sure how that was determined.

Mike

Mike
 

mtindor

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Even though some developers are working feverishly on TDMA CC support in apps like DSDPlus, OP25, BlueTail Tech P25RX (and probably others), it still isn't a "finished" thing.

If you are down in TX / OK and have the ability to capture updated data on the sites with standard FDMA CCs with Unitrunker, DSDPlus or some other app, please do so and paste the screenshots showing all of the peers / peer CCs / peer channel numbers.

If you are down in TX / OK and have the ability to capture raw audio (such as when using DSDPlus) on a CC that you know is a TDMA CC, please do so and then upload it somewhere and post a link -- This does not need done for sites for which it has already been done (Kenedy, Alice, George West, Freer, Beeville).

Thanks

mike
 
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