Denton County P25 II

Looking for someone knowledgeable of the new Denton County P25 II system. I bought a new Whistler WS1098 scanner, but none of the objects are decoding properly. The scanner stops sometimes, but there is either no audio or the audio is garbled/mechanical sounding. Am especially interested in rophy Club Fire and PD info. Any thoughts, links or help would be appreciated.

Are you scanning from a stationary location? Where about? Assuming you are in Trophy Club, hop on 114 East towards Grapevine, and see if things improve. The link at the bottom of this message has the transmitter sites. It's not uncommon to not be able to receive well, if you're between two or more sites.

Have you moved around the county to see if reception improves in different locations?

I'm in NE Tarrant county, and it's a little bit of a stretch for me to hear it, but it usually comes in from my home with a yagi antenna pointed generally north. In the car, I've heard it on my WS1095, driving in the same area.

I would make sure you only have in the control channels. 772.60625a 773.65625c 858.28750a 859.28750a. I think having all of the other frequencies programmed in only confuses the scanner, and makes it take longer for it to find the real control channel.

Denton County Public Safety (P25) Trunking System, Denton, Texas - Scanner Frequencies

http://www.radioreference.com/apps/db/?action=siteMap&sid=8438&type=fcc

BenScan, thanks for the reply. I live in Trophy Club and it's a fixed location. I'm using an outdoor discone antenna and I think my problem is multipath reflections. Maybe I need to swap out the discone for a yagi. Do you know a source?

You're welcome.
ScannerMaster, advertiser on this site, has several. I have a couple of the one at the link below. There maybe some local and less expensive sources, but I haven't looked. I was just reading where they (Denton County) added a site in Northlake, and that maybe what's giving you trouble.

Laird PC806N Yagi Base Antenna | Scanner Master

Good luck! It's very frustrating knowing that the scanners could be built differently to solve the problems of simulcast. I'm very close to putting my money into the Unication G5 pager(doesn't support Phase II yet) or real radios.

Laird Y8066 Yagi Base Antenna | Scanner Master

I use this one in Arlington with great results.

Thanks guys, I'll check them out.

73, Steve K5FR

K5FR said:

BenScan, thanks for the reply. I live in Trophy Club and it's a fixed location. I'm using an outdoor discone antenna and I think my problem is multipath reflections. Maybe I need to swap out the discone for a yagi. Do you know a source?

Click to expand...

You might first trying something simple and at little or no cost. Switch from the outside discone to an inside antenna (perhaps those for a handheld attached directly to your scanner). Since the issue is too much signal (yes, that's a real issue on simulcast systems) it may fix your problem quickly, easily, and inexpensively.

I had issues with the Plano system here at my house and the solution was a very surprising one. I pick up the system best when no antenna is attached to the scanner! Yes, you read that right, NO ANTENNA worked better than my outside discone. I discovered this totally by accident though. While working to resolve the issue I unplugged the cable from that scanner from the splitter for some testing. When I was finished testing some solutions (that didn't work) I was hooking things back up and failed to hook back up that scanner. I noticed that evening the Plano system was clear as a bell and the simulcast distortion issue appeared to be resolved. Although I was grateful to have fixed the problem I didn't know what I did to fix things. Later on, I found a cable that had both ends plugged into the splitter and another cable disconnected. After a bit of tracing, I discovered that the solution was really having only that short jumper connected to the Plano scanner with no antenna at all! Very weird, but hey if it works, I'm OK with that.

Now this may not work for everybody but it demonstrates what can work. I'm about a mile from the closest site so have very strong signals from it at my location. The problem was that that system has several sites so signals from more than one were reaching my scanner.

In your RF dense area, your poor radio is probably overwhelmed in the 700 & 800 bands. How does the "T" indicator look? Is it mostly solid, or is it barely on?

How many control channels do you have programmed? It is best to use just one, or, if your system cycles them, use only the ones in the rotation.

You can play around with the ADC gain (probably 0 or lower is best for you) and the DSP adjustment. These are in the global settings menu at the very end of the list (so use the up arrow to get to them).

Since these consumer scanners are marginal at best for receiving LSM (simulcast P25), it really takes a lot of experimentation to achieve good reception. It's usually possible if you work smart and long enough at it. Unfortunately, many get frustrated and give up.

I recommend ordering a $10 RTL stick and downloading SDR#. Use it with various antennas, locations, directions, and shields to help your experimentation. The software allows you to become more informed about the results of your changes.

I too recommend a Yagi. I find this one works pretty well (search this on Amazon: Phonetone 11db Outdoor directional Yagi 800Mhz/850MHz/900MHz GSM Antenna with N female connector for Cellular Mobile cell phone signal Repeater Booster Amplifier extender). You'll need a N to BNC adapter too.

For some systems, I find horizontal polarization works better. Also, blocking unwanted noise and "noise" from other simulcast towers is as important of a consideration as where you point the antenna.

Oh, and most importantly, turn your squelch setting all the way down. Along with this, scan just the P25 system.

Here are some links that include more information:

http://forums.radioreference.com/wh...ase-1-conv-squelch-questions.html#post2561597
http://forums.radioreference.com/whistler-scanners/332310-difficulty-staying-control-channel.html
http://forums.radioreference.com/mi...forum/331324-simulcast-distortion-buster.html

And I know there's much more on the topic. When searching, don't limit just to your model, there are 6-8 radio models that are all essentially the same.

AggieCon, thanks for the info and links, very good. The yagi didn't work, still too much multi-path. I'm going to try the Cantenna approach as several have had good luck with it so we'll see how it goes.

I'm sure you'll figure it out. I'm driving through tomorrow, and I am going to try to scan the system.

There is one certain system I can receive perfectly in my apartment if and (so far) only if I:

• Put a big, thick baking pan on top of a box at a certain height on my desk, with the pan oriented in a specific direction
• Hold my radio at a certain point on the pan
• Hold my radio at a certain height above the pan
• Use a specific antenna
• Hold my radio (antenna) at the proper orientation
• Position my body correctly relative to the next closest site.
• And then I can get near perfect decode.

In contrast, for the same system, using software defined radio (OP25) and the same antenna just standing on the edge of the box, I get the system fairly well. If I use the (cheap) telescoping antenna that came with the RTL software defined ratio on top of the pan, I receive perfect and consistent decode.


The points I am strongly stressing are: 1) these consumer scanner radios aren't the best for this specific purpose and 2) it takes a lot of trail and error (and patience) to find success for receiving LSM P25 unless you happen to live in a perfect sweet spot.

You forgot to mention you also have to hold your mouth just right and stand on one foot.

Yes that too. It probably matters what I had for lunch and the relative humidity as well.

I monitored the new Denton County P25 system this afternoon in Tarrant, Denton, and Grayson counties. I found it to be exceptional -- much better than Montgomery County's P25 system. I switched to the system around the time I passed 287 on 35W. I picked up traffic and had perfect voice decodes (so I don't know the southern margin on 35, I should have switched sooner). It did fine around downtown Denton. There was a small null northeast of TWU and another in Pilot Point. Otherwise, I had perfect coverage throughout the areas of the county I traveled (I was not in your far corner of the county). My scanner decoded well into Grayson county, even northeast of Collinsville (of course with dead zones in the lower areas here and there).

I was using my WS1080 inside of the truck with this antenna: (ExpertPower® 7.75" BNC-Male Dual Band Antenna found on Amazon). I also used an RTL with the stock telescoping antenna inside the truck. I think UniTrunker decoded the control channel till probably around highway 82 and 289, near the middle of Grayson County. Of course, this area isn't as built up as yours.

One note about "omni" directional antennas: even these can be used as directional antennas; they are only "omni" perpendicular to the antenna. Turn it horizontally, and you have a bi-directional antenna. Put a shield or reflector on one side, and you have a directional antenna.

I also looked at the topography of your area, as well as the tower placement.

I am unsure why you are having so much trouble. Perhaps very local interference, attenuation from structures, or maybe multipath. If you have a good view to your east, point your antenna to the Grapevine tower. The tower to your north should also be in reach.

However, I would like to confirm that you have your scanner programmed properly before you spend more time fussing with antennas and placement. I recommend driving around to find out if you are getting good decode on your scanner anywhere, even right below the tower.

Program only the control channel. As of earlier today, it was 859.2875. Make sure you squelch is all the way down so it is always open. Try programing a wildcard. With a high gain antenna, maybe you need to turn on your global attenuation. Make sure your talkgroups have a delay of at least .3 seconds. That why it will stay on them instead of bouncing back and forth on every little insult.

Other things I noted:

• The Corinth radios are pretty hot, perhaps a different model than the others or they have the gain up. I'd turn on auto gain control for the Corinth PD talkgroup. I heard them fine (great, actually), it just blasts out about twice the volume of the SO, though.
• I didn't hear any Lewisville traffic. I suppose they aren't using the system yet.
• There was some traffic on a TG not in the RR database, 483
• The busiest talk groups were the three SO patrol TGs, DC Fire Dispatch, and Corinth PD.

Of course, this is just from around a couple hours of monitoring.


I think this will be a fun system to listen to once Denton and the rest switch over. It would also be fun to work with someone to setup a software defined radio solution for recording the traffic.

AggieCon said:

Yes that too. It probably matters what I had for lunch and the relative humidity as well.

I monitored the new Denton County P25 system this afternoon in Tarrant, Denton, and Grayson counties. I found it to be exceptional -- much better than Montgomery County's P25 system. I switched to the system around the time I passed 287 on 35W. I picked up traffic and had perfect voice decodes (so I don't know the southern margin on 35, I should have switched sooner). It did fine around downtown Denton. There was a small null northeast of TWU and another in Pilot Point. Otherwise, I had perfect coverage throughout the areas of the county I traveled (I was not in your far corner of the county). My scanner decoded well into Grayson county, even northeast of Collinsville (of course with dead zones in the lower areas here and there).

I was using my WS1080 inside of the truck with this antenna: (ExpertPower® 7.75" BNC-Male Dual Band Antenna found on Amazon). I also used an RTL with the stock telescoping antenna inside the truck. I think UniTrunker decoded the control channel till probably around highway 82 and 289, near the middle of Grayson County. Of course, this area isn't as built up as yours.

One note about "omni" directional antennas: even these can be used as directional antennas; they are only "omni" perpendicular to the antenna. Turn it horizontally, and you have a bi-directional antenna. Put a shield or reflector on one side, and you have a directional antenna.

I also looked at the topography of your area, as well as the tower placement.

I am unsure why you are having so much trouble. Perhaps very local interference, attenuation from structures, or maybe multipath. If you have a good view to your east, point your antenna to the Grapevine tower. The tower to your north should also be in reach.

However, I would like to confirm that you have your scanner programmed properly before you spend more time fussing with antennas and placement. I recommend driving around to find out if you are getting good decode on your scanner anywhere, even right below the tower.

Program only the control channel. As of earlier today, it was 859.2875. Make sure you squelch is all the way down so it is always open. Try programing a wildcard. With a high gain antenna, maybe you need to turn on your global attenuation. Make sure your talkgroups have a delay of at least .3 seconds. That why it will stay on them instead of bouncing back and forth on every little insult.

Other things I noted:

• The Corinth radios are pretty hot, perhaps a different model than the others or they have the gain up. I'd turn on auto gain control for the Corinth PD talkgroup. I heard them fine (great, actually), it just blasts out about twice the volume of the SO, though.
• I didn't hear any Lewisville traffic. I suppose they aren't using the system yet.
• There was some traffic on a TG not in the RR database, 483
• The busiest talk groups were the three SO patrol TGs, DC Fire Dispatch, and Corinth PD.

Of course, this is just from around a couple hours of monitoring.


I think this will be a fun system to listen to once Denton and the rest switch over. It would also be fun to work with someone to setup a software defined radio solution for recording the traffic.

Click to expand...

How dare those darn Motorola ST's make this system sound good! Haven't they heard that P25 simulcast is supposed to suck??

Did you by any chance listen to the VHF analog FD simulcast? I believe it's for tone-outs only so it may not see much use.

I'll have to pay attention next time I hear it, but I believe Corinth's talkgroup is probably using Phase 2, which has a different sound than most of the other talkgroups, which are typically still Phase 1, since not all users have Phase 2 radios yet. That might account for the difference. I find my Uniden scanners don't sound as good, and are more difficult to hear with Phase 2 talkgroups, compared to Whistler.

I was driving a lot of the time, so I didn't pay attention to the digital mode icon. But that Corinth is the only one using TDMA makes sense to me, and the UniTrunker call history and channel log backs that up too.

A recent press release that I saw, mentioned an additional site was added and the VHF paging improved, when Denton County recently switched. I believe they are using VHF paging as well as the trunked system, but I do not know that for sure. They just switched recently, and I imagine as more of the users are able to upgrade radios, there will be more Phase 2. As I understand it, 99 out of a 100 radios on a talkgroup could be Phase 2, but it's the 1 that's Phase 1 that keeps things working as Phase 1, instead of Phase 1.

I believe the state school, jail, and public works are still using the analog system.

AggieCon, thanks for the very in-depth analysis of the Denton County P25 system. My scanner settings are as follows:
AGC - Search = enabled, Global AGC Mode = Global, Global AGC = enabled
Advanced DSP Settings - DSP Level Adapt = 64, ADC Gain = 0db, DAC Gain = 0db
TG Delay = 2 secs.
TG AGC = un-checked

All TG AGC modes are DG that I have seen.

I can copy ~95% of the system using a 440 MHz circular polarized Yagi that's part of my satellite system so I'm pretty sure my problem is the antenna and multi-path specifically. I'm in the process of installing a Wilson yagi http://www.amazon.com/Wilson-Electr...psc=1&redirect=true&ref_=od_aui_detailpages00 with a rotor to see if I can null the reflection(s).

I have a FunCube SDR receiver so I could hook it up to monitor the Denton system. Is UniTrunker software what I need to do this or are there others?

Many of the other Denton county TGs (like Lewisville) are still on the old analog system.

Glad you are seeing improvement. You might try turning auto gain control off (at the global level). I have mine disabled globally.

Confirm, is your squelch all the way down (most sensitive)? Do you have attenuation off at both the global and system levels? How many frequencies do you have programmed for the system?

Otherwise, I guess you are just in an unlucky location relative to this system. You're fortunate to have the flexibility for an outside yagi. With a motor, that will be lots of fun zeroing in on all of the systems in DFW.

What does the "T" icon look like on your various antenna setups?

Please do report with the new antenna, and perhaps share some pictures as well. Sounds like an exciting project. I might do the same one of these days.

I have a FunCube SDR receiver so I could hook it up to monitor the Denton system. Is UniTrunker software what I need to do this or are there others?

Click to expand...

UniTrunker routed to DSD+ will allow you to hear everything except the Phase 2 talkgroups (so just minus Corinth for the time being). You'll be able to keep better records of the traffic, new talkgroups, and your ability to decode. If you want to hear Phase 2, you'll need OP25. By the way, OP25 is the best way to listen to LSM P25. If you don't end up getting your scanner to work it well enough, OP25 will likely save the day.

SDR# is best for experimenting with different antennas, locations, gain settings, etc.

KE4EMQ pops

Just wondering my station is two 536 scanners attached to an outside comet discone ant with a one hundred foot run of rg8x on a ten high pole.. i also have a 436 and hp2 both using stock antennas i live between the denton and aubrey towers i am having none of the problems that i read about in this form . my take home fd radio is a moto apx 4000 set up by moto techs the scanners sound better then the apx 4000. i am a ham radio general and can not get any hf at all two different radios and antennas and nothing yet 2m/ 440 works fine does anyone have any answers to this thanks for any help.