American Electric Power (AEP) P25 WACN 92715

[DeaconHarry16]

When I got my RTLSDR from Amazon it came with a dipole kit. It is suction cupped to my bedroom window and runs a short piece of coax into the SDRRTL and then a USB cable to my surface pro7. I bought the 800 900 mhz antenna that you suggested earlier, which I assumed was made for cellular service. It does not do as good as the dipole.

 

[DeaconHarry16]

I adjusted the elements to length, used the DSD plus spectrum window to find a hotspot on my bedroom window, And the rest is history.

 

[firemantom26]

Thanks, Harry for the photos.

 

[nd5y]

More construction notifications in Texas filed yesterday:
WPCB210 Abilene (south of)
WPCB238 Cottonwood, Cross Plains (Cisco on license)
WPCB263 Throckmorton
WPLX404 Dickens
WQBP321 Cisco
WRKB227 Moran
WRMW879 El Dorado
WRMX419 Blackwell

 

[nd5y]

Well a few weeks ago the Mangum OK site rotated control channels and I quit hearing it. The neighbor sites all showed the CC as 854.9375. At times I could hear some weak signal that sounded strange and I thought it was something else interfering. Tonight the conditions are good and it sounds like the CQPSK modulation used in simulcast systems but It won't decode. On the scope it looks just like the city of Wichita Falls P25 simulcast system. I don't think there is another signal under it.

I think I'm getting the same thing from the new sites in Munday TX and Throckmorton TX. The EDACS CCs are gone and I'm getting something that sounds about the same as Mangum OK. Munday CC is 855.0625 according to its neighbors. It also sounds like CQPSK but I think there is another wideband data signal interfering.

I also quit hearing Woodson TX but I haven't figured out why. I haven't been able to receive anything farther south or west to see if Woodson & Throckmorton are showing up on any neighbor lists.

Back in the EDACS days Throckmorton was a neighbor of Oklaunion.

 

[mtindor]

Well a few weeks ago the Mangum OK site rotated control channels and I quit hearing it. The neighbor sites all showed the CC as 854.9375. At times I could hear some weak signal that sounded strange and I thought it was something else interfering. Tonight the conditions are good and it sounds like the CQPSK modulation used in simulcast systems but It won't decode. On the scope it looks just like the city of Wichita Falls P25 simulcast system. I don't think there is another signal under it.

I think I'm getting the same thing from the new sites in Munday TX and Throckmorton TX. The EDACS CCs are gone and I'm getting something that sounds about the same as Mangum OK. Munday CC is 855.0625 according to its neighbors. It also sounds like CQPSK but I think there is another wideband data signal interfering.

I also quit hearing Woodson TX but I haven't figured out why. I haven't been able to receive anything farther south or west to see if Woodson & Throckmorton are showing up on any neighbor lists.

Back in the EDACS days Throckmorton was a neighbor of Oklaunion.

Those wide "test pattern" like channels, which you (and I) suspect are SCADA are probably more local and stomping over top of the stuff you are really trying to find. Unfortunately, as time goes on it's only going to become more difficult because of that. Here in Ohio we were fortunate that almost always when they turned up a site the site would use the lowest licensed freq as the CC -- while the majority of those wacky wide signals are on much higher freqs for the most part in Ohio.

Mike

 

[nd5y]

Conditions are much better this morning.

This isn't test patterns or wideband SCADA. It sounds like Harris P25 control channels with some other modulation besides the usual C4FM. On a discriminator tapped PRO-2006 and looking at it on Unitrunker and DSD+ scope windows it looks like CQPSK.

Unitrunker 1.33, DSD+ 1.15 and a BCD396T won't decode it.

The 396T works fine on the city's Harris phase II simulcast system CCs. I'm close enough to one site that I don't get simulcast distortion at all.

I don't know what is going on. Maybe it's some other modulation than CQPSK even though it looks and sounds like it. Maybe they set some of the sites to use CQPSK for some reason or accidently.

 

[mtindor]

Conditions are much better this morning.

This isn't test patterns or wideband SCADA. It sounds like Harris P25 control channels with some other modulation besides the usual C4FM. On a discriminator tapped PRO-2006 and looking at it on Unitrunker and DSD+ scope windows it looks like CQPSK.

Unitrunker 1.33, DSD+ 1.15 and a BCD396T won't decode it.

The 396T works fine on the city's Harris phase II simulcast system CCs. I'm close enough to one site that I don't get simulcast distortion at all.

I don't know what is going on. Maybe it's some other modulation than CQPSK even though it looks and sounds like it. Maybe they set some of the sites to use CQPSK for some reason or accidently.

Strange, only in that there isn't a sigle simulcast site up here in Ohio/WV/MI/IN. But I admit things could be different down there. Although I don't particularly recall any FCC licenses down there with duplicate entries across multiple sites to suggest simulcast. And I don't think any of the sites would be CQPSK control channels if they weren't simulcast. And, if they were CQPSK you'd be able to decode them, no? I know I could with DSDplus.

Mike

 

[nd5y]

I know it's not simulcast, they appear to just be using what sounds like the same type of modulation as most simulcast systems.

Here are the sites I'm getting this on:
1F8 ?.? 854.5375 Throckmorton TX
1F8 33.33 855.0625 Munday TX
1F8 104.104 854.2125 Woodson TX
1F9 33.33 854.9375 Mangum OK

 

[mtindor]

I know it's not simulcast, they appear to just be using what sounds like the same type of modulation as most simulcast systems.

Here are the sites I'm getting this on:
1F8 ?.? 854.5375 Throckmorton TX
1F8 33.33 855.0625 Munday TX
1F8 104.104 854.2125 Woodson TX
1F9 33.33 854.9375 Mangum OK

I don't remember if you use UT or DSDPlus. And I don't remember if UT will decode CQPSK - I thought it would. I know DSDPlus does. At any rate, very strange goings-on down there

Mike

 

[nd5y]

Here in Ohio we were fortunate that almost always when they turned up a site the site would use the lowest licensed freq as the CC -- while the majority of those wacky wide signals are on much higher freqs for the most part in Ohio.

That's true for some of the sites here.
Some of the EDACS site used the first 4 lowest frequencies and the LCNs were in frequency order. Then the P25 and SCADA channels used higer ones.
Some of the EDACS sites used higher frequencies in random LCN order and the P25 site used the lowest ones.
Some of them it all appeared random.

 

[nd5y]

Unitrunker usually works fine on all the public safety phase I and phase II simulcast systems around here if the signal is strong enough and conditions are such that simulcast distortion is at a minumum.

I'm using the old free version of DSD+. It doesn't track trunked systems. It only shows the NAC and "TSDU" on a P25 CC but it works on C4FM and CQPSK and will decode on way weaker signals than Unitrunker.

 

[nd5y]

Mike I just noticed something. Look at the "Control" column. The sites with the suspected CQPSK modulation are using a band plan/LCNs that starts with 08 and the normal sites start with 00. I don't know what that means.



I haven't been able to receive Dickens or Matador at all yet. I haven't receive Aspermont for a couple months so I don't know if it is the same way. Matador CC is 25 kHz away from the city's normal CC of 855.9625 which would kill it anyway.

 

[nd5y]

I also noticed that normally only the phase II voice channels use the 08-xxxx LCNs.
The band plan used here in TX and OK 00 is 1 slot and 08 is 2 slots.
Maybe they are using some new Harris control channel format that actually has two time slots.

 

[DeaconHarry16]

Interesting I am hearing Wheeling area talk groups on 34.34. Are not identified in RR but have 22xx identifiers.
Sound like service type comms.
Harry

 

[nd5y]

Maybe they are using some new Harris control channel format that actually has two time slots.

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

 

[mtindor]

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

Hmm, if that is what they are doing they are sorta bleeding edge. I know that discussion you linked to was from 2018, so I guess it sure is possible. I know that none of the sites up here (or that we have seen anywhere else in the system) are configured as such, at least not yet. But that doesn't mean they wouldnt do it down in TX.

First I ever heard of that to be honest with you. I can't remember if you have the ability to monitor with DSDPlus or if you only use Unitrunker. I don't know if DSDplus would handle those types of systems out of the box as it exists now or not. But if you do use DSDPlus, you might want to consider using "r" in DSDPlus to record the raw audio of one of the control channels and then upload / post link to the raw audio here (because we would all be interested) or at the very least archive up a chunk of raw audio from one of the suspect control channels and send it to dsdplusfastlane@gmail.com .

If you are only using Unitrunker, I'm going to assume you are part of the UT group (which is either on Google Group or Groups.io - I forget which), as Ric would almost certainly be interested in some raw audio too, if indeed it turns out to be that they are running TDMA control channels down there.

Mike

 

[nd5y]

I only have DSD+ 1.15 and Unitrunker 1.0.33.6.
I'm not joining anything to get the lastest versions. I don't even know if Fastlane and UT V2 still work with discriminator audio. Unless this web site was abandoned, DSDPlus – Digital Decoder and there is another one I don't know about, They lied about making public releases every six months. In another thread somebody posted a link to the latest Unitrunker V2 file. I downloaded it and tried to install it but it won't work on WINE/Linux so I can't use it anyway.

Like I said before neither one will decode this and neither will a BCD396T.
DSD+ has command line switches for P25 only and P25-PSK only. Neither works and default auto mode select doesn't work.

I'll try to get audio samples next time there is a good enough band opening that one of those sites is full quieting.

Right now all I know is there are some sites showing neighbor CCs with the 2 slot band plan:

I have Unitrunker set so all marked control channels are blue, the the active control channel is red and voice channels are white.

 

[nd5y]

My PRO-2006 is out of alignment and the discriminator audio is probably distorted some. Here are some DSD+ 1.15 scope screen shots.

This is what a P25 C4FM CC looks like.


This is what the City of Wichita Falls Harris P25 simulcast system CC looks like. A bunch of positive and negative spikes. The AEP CCs that won't decode look almost the same as this.

 

[mtindor]

My PRO-2006 is out of alignment and the discriminator audio is probably distorted some. Here are some DSD+ 1.15 scope screen shots.

This is what a P25 C4FM CC looks like.
View attachment 106703

This is what the City of Wichita Falls Harris P25 simulcast system CC looks like. A bunch of positive and negative spikes. The AEP CCs that won't decode look almost the same as this.
View attachment 106704

Unfortunately I don't have any suggestions. You've already said you don't intend on joining any groups, buying anything, changing anything. Without real raw audio I don't know that anybody would be able to accurately diagnose what is going on. I certainly couldn't (even with raw audio) because I barely know what the hell I'm doing lol. Although I'm not totally convinced that any sites are running in simulcast or that any sites are actually using that talked-about TDMA control channel stuff. either could be true, but seems unlikely since they weren't like that when they first came online.

But if you really suspect that either it's simulcast or is using some TDMA CC stuff, you'd want to gather raw audio and send it somewhere, to somebody who knows what to do with it, in order to get it supported in UT or DSDPlus or whatever else.

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.

Mike