Dabbling in NXDN

So I finally did it, and purchased the TRX-2. The NXDN curiosity bug got me, and not sure what Uniden's plan on the x36 series scanners, I jumped the gun. I haven't seen too many database updates on NXDN, I'll assume not many here have investigated the other side yet. The EZ Scan software will be a little bit of a challenge and some patience and I will get the hang of it.

This morning, I did it the old fashioned way and pulled out my index cards, grabbed a cup of coffee and did some listening. I made some previous notes on "possible" NXDN data noise and went at it. I searched 450-455 Mhz., 460-465 Mhz, then 471-480 Mhz so far. I have checked the FCC database and it appears A-Beep has a commanding footprint in NXDN and all the other digital formats in and around the metro area.

My findings surprised me, as in previous formats the radio systems stayed within "boundaries"..450 Mhz. 460 Mhz. etc. I was seeing talkgroups across the board...452.2125 would also carry talkgroups on 472.000...all licensed to NXDN and carrying NXDN emissions per the FCC website. It wasn't simple as many paired frequencies carry different licenses and different frequencies. As of this writing, I have confirmed 18 frequencies in use on the A-Beep NXDN system.

I've been able to confirm the same talkgroups using all these frequencies...a couple of private ambulance companies are up there, E&R Towing (Handles CPD towing) I also heard. 5995x..(x is different talkgroups) and 20xx (x is different talkgroups) are the Private Ambulances. I'm sure there is alot more to discover, but that was a small sampling. It appears A-Beep is moving away from it's LTR and analog systems and going NXDN.

I'll update the database when I have confirmed information to share. RAN 6 (Radio Access Number) is present on 14 of the 18 confirmed frequencies, but I also have two RAN's of 7, three RAN's of 16, and one RAN of 24. It's another learning process, but I enjoy a good challenge.

More options:

- limit search with the NXDN box checked; in my area I have business users (DMR and NXDN) in the 150 mhz, 450-497 Mhz and even 860 Mhz ranges.

- Justin's search tool

I still find many users that are not correct in the FCC database ... say they are DMR or NXDN but aren't; are not licensed for digital but using it anyway.... I even have one around here I'm struggling to identify - the frequency isn't licensed in any way in my area best I can tell but it's DMR.

Kenwood uses A-Beep as one of their NexEdge trunking system case studies:
http://comms.kenwood.com/en/common/pdf/case_studies/nexedge_casestudies_beep.pdf

NXDN was designed to be a progression from LTR, so making the transition is pretty easy to do in phased steps. Kenwood NexEdge repeaters can be programmed/interfaced to run mixed mode (analog and digital) as well interface to an LTR controller as well as the NexEdge trunking interface.

troymail said:

More options:

- limit search with the NXDN box checked; in my area I have business users (DMR and NXDN) in the 150 mhz, 450-497 Mhz and even 860 Mhz ranges.

- Justin's search tool

I still find many users that are not correct in the FCC database ... say they are DMR or NXDN but aren't; are not licensed for digital but using it anyway.... I even have one around here I'm struggling to identify - the frequency isn't licensed in any way in my area best I can tell but it's DMR.

Click to expand...

Yes...did that, read the posts before I started. I programmed in about 5 Talkgroups for practice purposes including the Wildcard, Now all the Wildcard Talkgroups are coming up in Hex format despite I changed it to Decimal format via EZ Scan. Hmmm...back to the drawing board!

After a week, I'm still at it. I've been in the Whistler forum to try and figure out the best method of programming NXDN and from what I've been able to figure out, I've found out 1 system with all the "known" frequencies has been the way to go. I tried programming sites based upon the RAN, but that doesn't seem to make a difference with TRX-2 programming. The EZ Scan software took me a couple days to get a feel for, but now I'm comfortable using it.

A-Beep is also known as Diga-Talk in the Trunking database. This system is very impressive with the clarity and range. I don't think I've heard a user complain about "breaking up" or "digital garble". Their are many "business users" on this system which might not be of interest to some here, but then again other things don't interest all here so it's personal preference. What I have noticed is analog LTR is not very active and many of the bus companies, trucking companies and many others have converted to the Diga-Talk system. Fortunately not much encryption but the couple times there was an encrypted conversation, the TRX-2 emits a quiet "busy signal".

What I have noticed most, is very few of the frequencies that are listed in the database for this system are not correct. The Sears Tower site has many inconsistencies and that seems to be the "primary" site that is used with the RAN of 6. I've also been able to document 6 other RAN's and by cross checking the FCC database, I'm able to get an idea of the location of these different remote repeaters.

I enjoy a good challenge and like I said their are many users on this system. Midway Shuttle buses, Rental shuttles, Security, Trucking companies, School bus companies....if you can't find something on an analog LTR or MotoTRBO system, this will be the place to look.

I hope to make some contributions to the database, but I don't know how much interest there is or how many here have invested in the TRX series scanners. The licenses for this system are scattered all over the place, so that won't be the way to do it. I'll have to figure out a better way to contribute.

I've been searching and making notes since my last posting. I've been able to confirm some talk groups based upon conversations and locations mentioned. As I previously mentioned, the Sears Tower site appears to be the primary site used and have confirmed the Midway Airport site is used as a "spur" site. I've done some research and have found out certain users can be programmed to "lock on" a site instead of "roaming" all the sites. I suspect this would result in missed talk groups if you didn't have the correct site programmed.

Which brings me to site programming. I've received some excellent advice on how to set this up on the Whistler forums. As we've previously seen on Starcom and other simulcast systems, all that is necessary is to program is the closest site. In my case, RAN-24 is Midway Airport but have been able to confirm it as a "spur" site (NXDN term). I have yet to pick up a control channel and what I've been able to confirm, the Midway Rental Shuttles are "locked on" to this site. Ironically, the Employee Shuttles "roam" and RAN-6 (Sears Tower) "appears" to be the primary site talk groups programmed to "roam" lock on to first. So in my case (User location dependent), if I monitor only the Sears Tower site, I will not receive the Rental Shuttle talk group. Same goes if I only have the Midway Airport site...I will not receive the Employee Shuttles. They are run by 2 different companies, so this is the reason.

I mentioned before the frequencies for the Diga-Talk system are not all correct. I was able to do some research and found out their are many other sites I won't be able to monitor from my location with my TRX-2. However it appears any talk group that is "roaming" will be assigned to one of the RAN-6 site frequencies and may "simulcast" on one of the other site frequencies closest to the location. I've heard Superior Ambulance report on locations in Michigan City,IN as well as Rockford,IL. The only sites I have programmed are Sears Tower & Midway Airport.

My question is for the person(s) who submitted the frequencies for these sites. Did you base them on location and emissions via FCC license information or from searching? If it's from searching I'd be reluctant to delete all those frequencies that you submitted because I can't say I didn't miss 1 or 2 here and there. If it's from the FCC database, then I'd say let's correct them. Send me a message if you'd prefer and I'll submit my information afterwards.

I know there aren't too many that monitor NXDN because of the lack of scanners available. I know others have used computer programming over the years to monitor NXDN. I would suspect the future will open up as newer scanners will be NXDN capable. MotoTRBO, NXDN, P2...it's opening up some new avaenues for us and I hope others take advantage.

You have worked hard and it seems as if you and most everyone else can only take baby steps with these new systems. I am very interested in the new scanners and systems but so far I can not justufy the price of the scanners along with my lack of focused time to learn. It seems like there are not a lot of people out there learning and posting new info on what seems like complicated systems. I commed you on your hard work. I wish I could do it. I hope people are not losing interest in the hobby. I am borderline on my interest right now in part because of the complexity and learning curve of the scanners and systems. I thought I caught on pretty good when I bought my 396xt and 996xt but the new scanners scare the crap out of me. Again I commend you on your patience and hard work. Maybe sometime soon I will break down and purchace one of the Uniden or Whistler scanners. Or maybe a new scanner model in the future. Long live direct frequency entry.

I would never call this "work", but it's just a dedication to the hobby. We've been playing catch-up for many years as new systems are developed and introduced and suddenly we no longer here what we want. NXDN is just another example as most analog LTR users upgraded to it. MotoTRBO is another upgrade path. Most analog systems are being phased out with the selling point of "parts and radio availability" and the salespeople sell, and the vicious cycle continues. Encryption is becoming more popular as many users are promised "privacy".

I have also heard a railroad in the 150 Mhz band using NXDN on a repeater. It's possibly a patch, but I'd have to dedicate some time to figure it out. I do enjoy the repeater on railroad monitoring, but this might be the exception.

So yes, things are changing again around here. I'd really like to see the simulcast issue addressed at some point, but I think we'd see a $700 scanner if we got everything we wanted. In the meantime, I'm one of the lucky ones not to have encryption with everything I want to monitor. Hopefully others will upgrade to some NXDN so maybe we can identify talk groups and compare notes.

Bike The Drive Listening

Had a chance to sit down yesterday morning as the "Bike the Drive" event was taking place. I figured this would be a good time to listen to the Diga-Talk system to check on any new talk groups. Superior Ambulance contracts out to handle many of the large city events and I ended up holding on the Detail-1 channel. Very active as I expected, and a Command Post was set up to dispatch ambulances and bike teams to incidents. Citywide 6 was notifying the command post, but it's possible another channel or two was in use.

I submitted some changes to a couple sites to this system, so hopefully anyone who has NXDN capabilities will dabble along with me. A couple private ambulances are using the system, E&R towing, possibly O'Hare towing and countless others are up here. You never know what's next.

The TRX's sure appear easy to set up to monitor NXDN. Unfortunately, because they seem to require all frequencies and do not really use the CC for trunking (based upon what I've heard), they really don't give a whole lot of useful information about any site/system. For the real discovery, DSDPlus is needed. As an example, every site I've looked at on Diga-Talk (and I only looked at about six of them), all of them have channel numbers of "0". In reality, there is a channel number assigned to every frequency, and somebody really needs to make an attempt to determine them with DSDPlus monitoring along with the normal monitoring via scanner. DSDPlus requires the channel number for proper trunking, and I would guess that if Uniden comes out with NXDN support they will likely trunk NXDN using the control channel and will likely need to know the actual channel numbers assigned to each frequency.

FYI (for those scanning with a scanner), I see that at least two sites have 454 mhz frequencies. If you're using a scanner to scan, be aware that your scanner may be set to ignore paging spectrum. For instance, on my BCD436HP, it's called "Broadcast Screen", and if I have "Pager" enabled under "Broadcast Screen", it is likely going to skip the 454 mhz paging spectrum. I think the Whistler/GRE/RS scanners have something similar. So you might want to make sure you are truly scanning 454 mhz versus skipping right over it.

Also, if your scanner defaults to scanning a particular band in 12.5 khz steps, you might want to set it to scan the UHF band in 6.25 khz steps.

Looks like a fun system to map out. Hope you all have fun!

mike

mtindor said:

The TRX's sure appear easy to set up to monitor NXDN. Unfortunately, because they seem to require all frequencies and do not really use the CC for trunking (based upon what I've heard), they really don't give a whole lot of useful information about any site/system. For the real discovery, DSDPlus is needed. As an example, every site I've looked at on Diga-Talk (and I only looked at about six of them), all of them have channel numbers of "0". In reality, there is a channel number assigned to every frequency, and somebody really needs to make an attempt to determine them with DSDPlus monitoring along with the normal monitoring via scanner. DSDPlus requires the channel number for proper trunking, and I would guess that if Uniden comes out with NXDN support they will likely trunk NXDN using the control channel and will likely need to know the actual channel numbers assigned to each frequency.

FYI (for those scanning with a scanner), I see that at least two sites have 454 mhz frequencies. If you're using a scanner to scan, be aware that your scanner may be set to ignore paging spectrum. For instance, on my BCD436HP, it's called "Broadcast Screen", and if I have "Pager" enabled under "Broadcast Screen", it is likely going to skip the 454 mhz paging spectrum. I think the Whistler/GRE/RS scanners have something similar. So you might want to make sure you are truly scanning 454 mhz versus skipping right over it.

Also, if your scanner defaults to scanning a particular band in 12.5 khz steps, you might want to set it to scan the UHF band in 6.25 khz steps.

Looks like a fun system to map out. Hope you all have fun!

mike

Click to expand...

Yes Mike, you are correct as all that's needed is the frequencies, and it doesn't appear to need to be programmed in a specific order. I keep going back and forth with the control channel being programmed in or not as not having it programmed doesn't appear to have a bearing on monitoring this system. What I have discovered is RAN's do matter. Very similar to site programming if users happen to be not close, and the radios are associating with different sites and I don't program all the sites in, I'd suspect I'll miss half the conversations. Others have told me not to program in all the sites, so the jury is still out.

Ideally, the Uniden programming would work well in my opinion if they decided to take a shot at NXDN and used the control channel. I could set up a System, then add the Sites and program in all the known talk groups and have the LCN finder determine the frequency order would be ideal. I have that on a couple of my Systems now, so it would be a breeze. However the concentration seems to be on MotoTRBO now and not sure if it will ever happen. On the other hand, if Whistler updated their firmware to do that, well then that would work too.

Alot to hear on this system, and hoping eventually a firmware upgrade from either Uniden or Whistler would spark the interest. Time will tell.

werinshades said:

Yes Mike, you are correct as all that's needed is the frequencies, and it doesn't appear to need to be programmed in a specific order. I keep going back and forth with the control channel being programmed in or not as not having it programmed doesn't appear to have a bearing on monitoring this system. What I have discovered is RAN's do matter. Very similar to site programming if users happen to be not close, and the radios are associating with different sites and I don't program all the sites in, I'd suspect I'll miss half the conversations. Others have told me not to program in all the sites, so the jury is still out.

Ideally, the Uniden programming would work well in my opinion if they decided to take a shot at NXDN and used the control channel. I could set up a System, then add the Sites and program in all the known talk groups and have the LCN finder determine the frequency order would be ideal. I have that on a couple of my Systems now, so it would be a breeze. However the concentration seems to be on MotoTRBO now and not sure if it will ever happen. On the other hand, if Whistler updated their firmware to do that, well then that would work too.

Alot to hear on this system, and hoping eventually a firmware upgrade from either Uniden or Whistler would spark the interest. Time will tell.

Click to expand...

Actually. . . .

I've been playing with the local NXDN system with a TRX1 here in my neck of the woods, and finding that not only do I need all frequencies, I also have to have the control channel, and the frequency channel ID numbers as well. It just would not track correctly without all those.

Once I got all the frequencies entered it worked a bit better, then the control channel and it was better still, but I was still missing transmissions regularly until I figured out and entered the channel ID numbers. Once I got that squared away it works flawlessly. So, I suspect it is pulling data from the control channel and using the Channel ID information.

And it can be pretty entertaining to listen to. It appears that AAA (or at least a pretty large number of tow companies) are using this system; tow truck drivers can be quite entertaining. Throw in some of the business users who aren't always too careful about what they say on the radio and you've got minutes of entertainment at your fingertips.

I am hoping Uniden comes out with an NXDN upgrade for the 436; with the more recent versions of the DSP the TRX1 handles P25 simulcast very nicely and I have no complaints there. In my opinion the GRE/Whistler DSP algorithms have always given much better sounding audio, so the TRX1 is rapidly becoming my go-to scanner for public safety monitoring because of the Scan List and V-Folder architecture; the 436 is getting used more for business system monitoring.

wa8pyr said:

Actually. . . .I've been playing with the local NXDN system with a TRX1 here in my neck of the woods, and finding that not only do I need all frequencies, I also have to have the control channel, and the frequency channel ID numbers as well. It just would not track correctly without all those.

Once I got all the frequencies entered it worked a bit better, then the control channel and it was better still, but I was still missing transmissions regularly until I figured out and entered the channel ID numbers. Once I got that squared away it works flawlessly. So, I suspect it is pulling data from the control channel and using the Channel ID information..

Click to expand...

I will give this approach a try as under my current set up, I'm still missing transmissions. I do not have have DSD+ capabilities, but was sent a couple of screen shots and will program accordingly. I did notice a couple missing frequencies, but I will try to slot them in.

It's difficult to tell if the NXDN control channel plays any role here. I do see the flashing "T" when I have the system in, but not sure if it's actually reading the data or just skipping over it and since the scanner has seen a control, it shows the "T". I'm not getting much feedback from Whistler, so assuming their not sure either.

As far as Uniden goes, that could be one of the issues in the release delay. All previous digital trunking formats have given us a control channel and sending out data which they were able to decode. Taking a guess here, but possibly the NXDN manufacturers are not allowing Uniden the rights to decode in a scanner? I know there are individuals decoding via DSD software and other means, but this is probably not the same.

If Uniden did release a firmware that decoded NXDN control channels/LCN. it would probably work very well. But...until this happens, I'll just keep tweaking my TRX-2. I'll post later with my findings...thanks for the info.

Happy first day of Summer! I've been enjoying the weather a bit, so can't say I've dedicated as much time to my NXDN dabbling as previously. The one thing I can say is the control channel is not being decoded despite claims it was in previous firmware releases on the TRX series. I'm able to eliminate it from my sites and it makes no difference in monitoring. In the Diga-Talk system I monitor, I have divided up the sites as it was suggested and with the help of a user with DSD capabilities, put the frequencies in "order" similar to monitoring an LTR system. While I can say their is some improvement, their is no monitoring a large system 100% correctly. All the frequencies are being "scanned" for activity, and if you program Talk group ID's like I do, the scanner does a pretty good job. I'm by no means disappointed as I'm content to know I can monitor NXDN if needed. For a smaller system, these issues will not be a problem.

I submitted some talk group info to the database, and will update when I can confirm. Many of the school bus companies will have limited conversations I suspect, but all the other daily activity continues.

I have submitted suggestions to Whistler for possible firmware upgrades or future scanner features. The two "biggies" would be NXDN control channel decoding, and 3.125 khz frequency acceptance. Some frequencies are using this format, and the scanner "rounds off" these frequencies, so not sure if it's being received in the NXDN stream.

So if Uniden folks are reading this, here is where you could excel in a potential firmware upgrade. I'm going to go out on a limb here and suspect Uniden's delay is they don't have the permission to decode NXDN control channel data stream in the form of a scanner...yet. If this does happen, will the 436/536 have the necessary availability to do so? Provoice, MotoTRBO, P25...don't know if their's enough room in the car for all the kids?