American Electric Power (AEP) P25 WACN 92715

[nd5y]

If you're running Linux, then if you've ever ran OP25 before you might try running OP25 and see what it thinks of that signal.

I missed this part. I tried to compile and install OP25 a couple years ago and couldn't get it to install properly let alone run. I don't know why. I might try to do it again on a MX Live USB and see what happens. I don't want to try that on my good installation.

 

[mtindor]

I missed this part. I tried to compile and install OP25 a couple years ago and couldn't get it to install properly let alone run. I don't know why. I might try to do it again on a MX Live USB and see what happens. I don't want to try that on my good installation.

OP25 is pretty sweet. Although if what you are hearing is indeed this newfangled TDMA control channel stuff, I have my doubts that OP25 supports it either. But, I'm betting that the OP25 crew want to support it if it is.

Mike

 

[scannerboy02]

I did some searching for more information about the high velocity data channel and came across a post on this forum talking about it as part of the AEP system.

P25 repeaters

P25 Phase II: As far as I know there is no ham P25 Phase II out there. I consider P25 Phase II and DMR to be kissing cousins and Phase I is kin to...

forums.qrz.com

"Today the minimum P25 Phase 2 configuration requires 3 channels; 1 Controller, 1-Voice channel that carries 2 voice time slots (TDMA), and 1 High Velocity Data channel."

I also found that Harris seems to be pushing this feature to a lot of utility customers so I'm sure it will be seen on many new P25 systems.

 

[nd5y]

I tried to compile and install OP25 a couple years ago and couldn't get it to install properly let alone run. I don't know why. I might try to do it again on a MX Live USB and see what happens.

I wasted about 3 hours on OP25. I got it to build and install but not run properly. It looked like it couldn't find some files. I can't find good information on how to use discriminator audio instead of an RTL-SDR.

OP25 is above my pay grade. I'm not messing with it any more.

 

[mtindor]

I wasted about 3 hours on OP25. I got it to build and install but not run properly. It looked like it couldn't find some files. I can't find good information on how to use discriminator audio instead of an RTL-SDR.

OP25 is above my pay grade. I'm not messing with it any more.

Been a few years since I installed it. Was always a feeling of "more pain than it was worth" to get it operational, but it really did work well. I probably will never do it again lol.

 

[ralexander5]

Attached is a shot of the CC of the Georgewest TX site captures from DSPplus. Also included the FM output and raw audio from DSDplus. Same signal is seen on Beeville an Alice sites.

 

[mtindor]

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

I've been told 48 or 96 khz sampling, saved as a 16-bit wav should be fine.

I suspect there should be enough of a recording made to allow as much useful unique data to be collected. That could result in a pretty big wav file, one that after zip/rar/tar.gz'ing may still be 10-100 MB in size.

Mike

 

[mtindor]

Attached is a shot of the CC of the Georgewest TX site captures from DSPplus. Also included the FM output and raw audio from DSDplus. Same signal is seen on Beeville an Alice sites.

Great job on the raw audio. If you haven't, you should send to dsdplusfastlane@gmail.com. And if you can, perhaps try and record a full minute or three, archive that up, and it'll probably be too big to ship via email (even zipped) but maybe upload it to some service - where a link can then be provided for dsdplusfastlane@gmail.com to download it. I only suggest that because there will be even more information contained in a CC recording (at least there are chances of that) than there might be with a brief few-second recording. Of course if the site is totally idle, 30 seconds is probably good. Not sure how you'd know, under these circumstances, whether a site was idle or not unless you happened to have monitored voice traffic on another freq of that system while you were recording raw audio.

thanks

 

[nd5y]

Attached is a shot of the CC of the Georgewest TX site captures from DSPplus.

That's what the non-decoding control channels look and sound like in my area.

 

[scannerboy02]

That is also what I am getting on the Duke Energy sites in my area.


From my research into the high velocity data channel, if I am understanding it correctly, it is different than a TDMA control channel. The high velocity data channel uses TDMA to pass data, as most P25 sites use FDMA for data. This basically allows the site to pass twice as much data using a single frequency.

My understanding is that the site would still have a control channel (be it FDMA or TDMA) in addition to a high velocity data channel. What I have been unable to find so far is if a site can run a high velocity data channel without having a control channel on the air. Knowing this would likely help us identify if what we are hearing is a high velocity data channel or a TDMA control channel.

I would also think the high velocity data channel would not be active 24/7, it would only be active while passing data. The signal I am hearing is active 24/7, like a control channel would be.

 

[nd5y]

From my research into the high velocity data channel, if I am understanding it correctly, it is different than a TDMA control channel.

Correct. Two totally differnt things. HVD is over 20 kHz wide. P25 is 8 kHz wide. You can easily tell the difference by listening to it in analog FM.

The high velocity data channel uses TDMA to pass data, as most P25 sites use FDMA for data.

I don't know if HVD is TDMA or not.

My understanding is that the site would still have a control channel (be it FDMA or TDMA) in addition to a high velocity data channel. What I have been unable to find so far is if a site can run a high velocity data channel without having a control channel on the air.

So far in this area it I have not seen a site that only has HVD.

I would also think the high velocity data channel would not be active 24/7, it would only be active while passing data. The signal I am hearing is active 24/7, like a control channel would be.

In this area all HVD channels are continuous.

All the new AEP sites here have a control channel, they broadcast at least two alternate control channels, they have usually two HVD channels, and they can rotate stuff around.

As far as I can tell any channel can be P25 CC, P25 voice or HVD. Sometimes the HVD channel will be what the CC is sowing as an alternate CC.

Running Unitrunker on the EDACS system I saw a lot of data iCalls from the SCADA RTUs several times a minute. So far on the P25 system I have not seen anything but normal voice radio affiliations and voice calls.

I have no idea if the SCADA RTUs use the control channel like a voice radio and Unitrunker can't recognize it, or if they exclusively use HVD. I have no idea if the HVD channels are actually carrying any traffic.

 

[nd5y]

Running Unitrunker on the EDACS system I saw a lot of data iCalls from the SCADA RTUs several times a minute.

Like this

 

[scannerboy02]

Are the HVD channels licensed for more than 12.5 kHz? If they are running over 20 I would think they would need some kind of authorization to run wider than the 12.5 channels in the band.

 

[nd5y]

Are the HVD channels licensed for more than 12.5 kHz? If they are running over 20 I would think they would need some kind of authorization to run wider than the 12.5 channels in the band.

Yes. Most of the license here have these emission designators.
8K10F1D
8K10F1E
9K70D1W
9K80D7W
18K7D1W
19K0D1W
20K0F1B
20K0F1E
20K0F2B
20K0F3C
20K0F3D
20K0F3E

The first 4 characters are the bandwidth.
Narrowbanding didn't incude 800 MHz. They are probably all coordinated for 20 kHz.
EDACS usually only had 20K0 designators.
HVD is probably 18K7D1W and 19K0D1W.

 

[scannerboy02]

Yes. Most of the license here have these emission designators.
8K10F1D
8K10F1E
9K70D1W
9K80D7W
18K7D1W
19K0D1W
20K0F1B
20K0F1E
20K0F2B
20K0F3C
20K0F3D
20K0F3E

The first 4 characters are the bandwidth.
Narrowbanding didn't incude 800 MHz. They are probably all coordinated for 20 kHz.
EDACS usually only had 20K0 designators.
HVD is probably 18K7D1W and 19K0D1W.

What you are hearing may be different than what I'm hearing then. The signal I'm getting in on frequencies licensed to the P25 trunking sites with 8K10F1D, 8K10F1E, 9K70D1W and 9K80D7W.


I was told by a Unication dealer that the G series pagers are capable of working on a TDMA control channel so I programmed one of my G5's with the frequencies and "wild card" ID's and so far the pager in not latching any of the sites so either the pager is NOT capable of working with a TDMA control channel or what I'm hearing is not a TDMA control channel.

 

[scannerboy02]

I'm doing some more reading on the high velocity data channel and it appears it is an add-on feature of a P25 trunking system so theoretically the system would need a control channel to tell the subscriber devices what channel to use.

I'm guessing this is why the HVDC is being shown as an alternate control channel on the system. Which makes me feel that what I'm hearing is more likely a control channel being that I am only hearing a signal on one channel per site.

 

[mtindor]

Great job on the raw audio. If you haven't, you should send to dsdplusfastlane@gmail.com. And if you can, perhaps try and record a full minute or three, archive that up, and it'll probably be too big to ship via email (even zipped) but maybe upload it to some service - where a link can then be provided for dsdplusfastlane@gmail.com to download it. I only suggest that because there will be even more information contained in a CC recording (at least there are chances of that) than there might be with a brief few-second recording. Of course if the site is totally idle, 30 seconds is probably good. Not sure how you'd know, under these circumstances, whether a site was idle or not unless you happened to have monitored voice traffic on another freq of that system while you were recording raw audio.

thanks

@ralexander5 If you are able to gather a longer duration capture of raw audio from a suspect P25 TDMA control channel and don't want to hassle (too much) with wear to put it, send an email to mtindor at gmail and I can provide you with an FTP login to upload a nice chunk of zip'd / rar'd / tar.gz'd raw audio to a reputable site (my aa8ia.org, ovscan.com or even the dsdplus.com website). I'm just trying to encourage somebody who has access and the tools to upload a couple minutes of raw audio, which even compressed can end up being quite a substantial upload. Shoot me an email if you are interested.

Thanks

Mike

 

[mtindor]

Attached is a shot of the CC of the Georgewest TX site captures from DSPplus. Also included the FM output and raw audio from DSDplus. Same signal is seen on Beeville an Alice sites.

From your raw audio clip... and this information is posted so that hopefully somebody on the forum who is experienced in processing this type of raw audio and extracting useful info from it will do so and elaborate.

The P25 audio sample received yesterday is from a Phase II signal that
is broadcasting D1 (hex) DUID values.

Raw 320 bit data units:

C774690346444760C2983B685718201A222222200A00696D92563E8AA51468540C882291BACFE689
C720690302444360C2983F2853608068888888802C01F5B74958FA2A9451A1503224DB46EB3F9E75
C7358010000000003FDFF08098888888888888802C0BC965FA432C5F617313EDB8587BAAAEAEB6A5
C71E4B0B20C28120FC90408098888888888888802C138492A212E905ABF24081189EAF1762A29F11
C71EC1249C547E2096970002C0807888888888802C1DDD3923DF195DBE75D1C3093D0155F4FA3481
C71E4B0B21268120C290408098888888888888802C28E090CA4C24C42EA0C2A59FD266EA79409EE9
C71E0103CB0D83CB0D90108098888888888888802C6C40C5F9EDB174109372EE3F116D2ED1F78531
C71E4B0B20FC81212690408098888888888888802C7A4A05D41E7953C809A0AB00056228581D15C1
C723E901C28980028210B88888888888888888802CAF0ACFD60E2B68558591CD866DCE13D13E2F05
C71E810C7E0B0B209697008098888888888888802CED5A399C5996B544C991A06AF7BD944B002DD5

The first half of each data block appears to be a payload, with the
second half containing forward error correction data.

Payloads with embedded DUID bits removed:

1DD1A40D19111D830A83B685718201A222222200A0
1C81A40C09110D830A83F2853608068888888802C0
1CD6004000000000FFFF08098888888888888802C0
1C792C2C830A0483F20408098888888888888802C1
1C7B04927151F8825A70002C0807888888888802C1
1C792C2C849A04830A0408098888888888888802C2
1C78040F2C360F2C360108098888888888888802C6
1C792C2C83F204849A0408098888888888888802C7
1C8FA4070A26000A080B88888888888888888802CA
1C7A0431F82C2C825A7008098888888888888802CE

 

[ralexander5]

Mike, Link sent sent via mail of location for larger samples. DSDplus guys have acknowledged receipt of a sample.

 

[mtindor]

Mike, Link sent sent via mail of location for larger samples. DSDplus guys have acknowledged receipt of a sample.

Thank you!