American Electric Power (AEP) P25 WACN 92715

[scannerboy02]

This might be what AEP is doing down here.
The link in the first post in this thread still works.

P25 TDMA Control Channel

I read with great interest an article published in April, 2018 issue of The Spectrum Monitor magazine regarding the introduction of the P25 TDMA mode Control Channel to the P25 Suite of Standards, and how it will benefit system/radio subscribers, along with more efficient use of the RF spectrum...

forums.radioreference.com

I was doing some reading up on TDMA control channels last week and it got me to thinking that (not to hijack this thread) this is very possibly what we are calling the "test" signals being heard on the Duke Energy system. If this is what we are hearing and they are running TDMA control channels on the AEP system as well as the Duke system that will be VERY interesting and I'm guessing we are going to need some new radios/scanners/software


Edit: I believe both systems are being installed by the same company.

 

[mtindor]

I was doing some reading up on TDMA control channels last week and it got me to thinking that this (not to hijack this thread) is very possibly what we are calling the "test" signals being heard on the Duke Energy system. If this is what we are hearing and they are running TDMA control channels on the AEP system as well as the Duke system that will be VERY interesting and I'm guessing we are going to need some new radios/scanners/software


Edit: I believe both systems are being installed by the same company.

I can only suggest that if you want to find out if those "test signals" are really test signals or something that should/could be decodable, that you consider capturing raw audio using "r" in DSDPlus of one of those channels and the archived wav file (or a link to it) to dsdplusfastlane@gmail.com . Or post a link to some raw audio on the forum somewhere (for somebody with knowhow to be able to make a determination). And those signals are wide -- if I remember correctly they were 20 khz signals, or maybe even 25 khz signals. So you'd have to capture raw audio with the widest filter setting possible.

That's the same thing that would need done for whatever nd5y is running across in his territory. Otherwise, there is no way for anybody anywhere to add some sort of support for it (if it indeed is something more than a test pattern) unless they have some raw audio to work with.

Mike

 

[nd5y]

How long have these Duke test signals been on the air?
Does the same frequency show up as a neighbor CC on other sites?

I have seen a few different systems that installed new sites.
There is some type of C4FM signal that only has a NAC and it only lasts for less than an hour. Usually just a few minutes. It's probably just for transmitter alignment.

AEP has some type of SCADA that is probably integrated into the P25 system but the SCADA channels don't look or sound like P25.

 

[scannerboy02]

I can only suggest that if you want to find out if those "test signals" are really test signals or something that should/could be decodable, that you consider capturing raw audio using "r" in DSDPlus of one of those channels and the archived wav file (or a link to it) to dsdplusfastlane@gmail.com . Or post a link to some raw audio on the forum somewhere (for somebody with knowhow to be able to make a determination). And those signals are wide -- if I remember correctly they were 20 khz signals, or maybe even 25 khz signals. So you'd have to capture raw audio with the widest filter setting possible.

That's the same thing that would need done for whatever nd5y is running across in his territory. Otherwise, there is no way for anybody anywhere to add some sort of support for it (if it indeed is something more than a test pattern) unless they have some raw audio to work with.

Mike

I am unfortunately unable to copy a clean signal from any of the sites from my home so I will need to go mobile to do this, but I will work on it this week.

 

[scannerboy02]

How long have these Duke test signals been on the air?

The Duke "test" signals have been showing up from site to site as the system is being built out. The first one I heard was in late 2020, I'm getting it on just about every site in my area (Cincinnati, Ohio) now.

Does the same frequency show up as a neighbor CC on other sites?

They don't have any existing sites, this is a new system being built from the ground up.

I have seen a few different systems that installed new sites.
There is some type of C4FM signal that only has a NAC and it only lasts for less than an hour.

AEP has some type of SCADA that is probably integrated into the P25 system but the SCADA channels don't look or sound like P25.

From my ears, I'm fairly sure this is some kind of P25 signal. It won't decode on any software I have, and I have a bunch of different software I use.

 

[nd5y]

The Duke "test" signals have been showing up from site to site as the system is being built out. The first one I heard was in late 2020, I'm getting it on just about every site in my area (Cincinnati, Ohio) now.

You say each site has this. Is that in addition to a normal P25 control channel?

 

[scannerboy02]

You say each site has this. Is that in addition to a normal P25 control channel?

No, no normal P25 control channel at all just the "test" signal.

 

[mtindor]

You say each site has this. Is that in addition to a normal P25 control channel?

I think he is referring to Duke Sites, and no P25 activity has been noted yet on Duke up in Ohio. The AEP P25 sites in Ohio (at least the ones around East Ohio) all have P25 control/voice channels plus one or more 20-25 khz wide signals of some sort, and have for a year or two now.

mike

 

[nd5y]

No, no normal P25 control channel at all just the "test" signal.

That's probably different than what AEP is doing in TX & OK then.

 

[scannerboy02]

I think he is referring to Duke Sites, and no P25 activity has been noted yet on Duke up in Ohio. The AEP P25 sites in Ohio (at least the ones around East Ohio) all have P25 control/voice channels plus one or more 20-25 khz wide signals of some sort, and have for a year or two now.

mike

This is correct, what I am hearing is in reference to the Duke system NOT AEP, although I believe they are being installed by the same company. The last time I checked on the AEP sites near me they were running normal FDMA control channels.

I am not in range of any of the AEP sites, I can hear several Duke sites from my house but the signal isn't very clean so I need to be mobile to do any analyzing of either of them. This makes things a little challenging to investigate.

 

[scannerboy02]

That's probably different than what AEP is doing in TX & OK then.

I will need to do some more investigating but I'm starting to think it's actually the same thing. My thinking (and right now it's just my thinking) is that they are transitioning the AEP sites from FDMA control channels to TDMA control channels and being that the AEP system started before the Duke system they are going to start the Duke system with TDMA only control channels.

It's also possible these two systems may already be or could become part of the same wide area system.

 

[mtindor]

Here is some raw audio from An Ohio AEP 25 khz non-decodable channel

Site 1F6-26.26 Steubenville
854.2625c
855.1375a
855.4125a
856.2875 - AEP-25KHZ.png
857.6625 - same signal/sound as the AEP-25KHZ.png
858.8875 - AEP-15KHZ.png

Two wav files in the directory mentioned below -- the larger one is 856.2875, one of the 25 khz sigs. The smaller wav is 858.8875 (a 15 khz'ish signal that sounds like just an FM-modulated signal with a tone imposed upon it.

854.2625 is a typical C4FM P25 CC. 855.1375 / 855.4125 are the typical TDMA voice channels. No activity right now, and no reason for me to record it as it is typical PII voice when it is active.

Index of /AEP

 

[Mattsenft]

I believe the data that is confusing everyone and not decoding as a standard control channel is the Harris TDMA High Velocity Data. I believe it is probably deployed on this system as it gives an OpenSky-esque data flow.

 

[mtindor]

I believe the data that is confusing everyone and not decoding as a standard control channel is the Harris TDMA High Velocity Data. I believe it is probably deployed on this system as it gives an OpenSky-esque data flow.

Never heard of that High Velocity Data, but makes sense. Yes, very OpenSky-ish when you look at the shape in a waterfall, and also sounds OpenSky-ish as well. Thanks for chiming in with that. I think that is at least one mystery solved.

Mike

 

[nd5y]

I believe the data that is confusing everyone and not decoding as a standard control channel is the Harris TDMA High Velocity Data. I believe it is probably deployed on this system as it gives an OpenSky-esque data flow.

There are two different things.
wideband data
control channels that don't decode

 

[mtindor]

There are two different things.
wideband data
control channels that don't decode

We need raw audio for any nondecodable channel that you believe is a control channel. If I had any channels like that up here, I'd post the audio. I have no such channels up here.

 

[nd5y]

I lied about my DSD+ version. I'm using 1.101.

 

[Mattsenft]

In addition to the TDMA HVD feature, Harris rolled out a TDMA control channel in the same system release. Most of the these features were designed to emulate the features that OpenSky users had by giving them something similar in P25. I have not seen any of the TDMA control channel deployments in systems around me.

 

[nd5y]

We need raw audio for any nondecodable channel that you believe is a control channel.

That could take a while. So far none of these are appearing on sites that I can copy all the time.

Somebody needs to specify the best file format, sample rate, etc. to use.

 

[mtindor]

That could take a while. So far none of these are appearing on sites that I can copy all the time.

Somebody needs to specify the best file format, sample rate, etc. to use.

I'm not sure of that. But I'm going to attempt to find out. Are you sure you don't want a copy of DSDPlus FL? If you, shoot me an email at mtindor at gmail and i'll dialog with you there. I'd have asked you in a PM, but you don't accept PMs.

If I find out specifics about audio format I'll let ya know.

Mike