BCD436HP/BCD536HP: Hytera DMR XPT question

[kc5igh]

Greetings:

Has anyone out there ever tried to monitor a Hytera XPT (Extended Pseudo Trunking) system with their Uniden scanners?

It took a while to figure out, but I'm pretty certain that the nearby casino I've been trying to program as a NXDN single-channel, Tier 2, or Tier 3 trunked system is actually a Hytera XPT operation. My BCD436HP is the radio that displayed "XPT" during voice transmissions.

The problem I'm encountering is that the XPT system seems to put out a non-audible beacon of some sort that keeps my BCD436HP and BCD325P2 locked on the frequency between voice traffic signals. I haven't tried monitoring that system with my SDS100, but I doubt it will work any differently than my other two NXDN-capable Uniden scanners. I've tried programming the system in conventional, trunked (single-channel, Tier 2, Tier 3), digital-only, search on and off modes, etc, but nothing seems to work when it comes to filtering out the non-audible "beacon" mentioned above so that the radio can move on to other channels.

As far as I can tell so far, the system uses only one UHF frequency (451.475), one "color" (10), and both slots (1 and 2, of course) in the course of a day. I've occasionally seen color "7" flash, but that's a rarity, and programming the channel as color-10-only didn't seem to have an effect on filtering out the "beacon" either.

My Whistler TRX-1 isn't capable of monitoring the system as a true trunk-tracker, but it doesn't get hung up on the "beacon" as do the Uniden scanners. It will resume scanning when the voice traffic stops. They all work great if all I want to do is monitor the one channel, but I'm not certain about what else I might be missing. To make matters even more confusing, when I programmed the system as a single-channel trunked system, I was picking up talkgroup numbers that seemed to separate housekeeping, gaming, security traffic, so I'm not certain about what's actually going on here. I'm pretty sure the XPT system is designed to support separate "channels" or "talk groups," and I'd like to be able to get my scanners to identify which one is which . . . it at all possible.

Any ideas or suggestions would be appreciated!

Thanks.

-Johnnie (KC5IGH)

 

[ka3jjz]

Yes, keep in mind Whistler never paid the royalty fees for DMR, so all their scanners can do is decode the audio.

I can't put my finger on this, but I know that Hytera decoding and trunking has been identified as an issue with Uniden scanners. Yes, the firmware supposedly handles it, but not very well. Unfortunately, they've been unable (or unwilling) to share the proper procedures for programming systems like this, and folks have had to figure it out on their own

It would be helpful to know precisely what it is you are decoding...the URL in the database (if it's there) would suffice.

RRDB | New Mexico Scanner Frequencies and Radio Frequency Reference

Scanner Frequencies and Radio Frequency Reference for New Mexico (NM)

www.radioreference.com

If it's not, you're going to need to do a little digging. It looks like XPT systems might need to be in LCN order. Did you check this?

Mike

 

[ka3jjz]

Is this the system you're trying to hear?

Code 3 Service XPT Trunking System, Various, New Mexico

Code 3 Service XPT Trunking System Profile

www.radioreference.com

Mike

 

[kc5igh]

Yes, keep in mind Whistler never paid the royalty fees for DMR, so all their scanners can do is decode the audio.

I can't put my finger on this, but I know that Hytera decoding and trunking has been identified as an issue with Uniden scanners. Yes, the firmware supposedly handles it, but not very well. Unfortunately, they've been unable (or unwilling) to share the proper procedures for programming systems like this, and folks have had to figure it out on their own

It would be helpful to know precisely what it is you are decoding...the URL in the database (if it's there) would suffice.

RRDB | New Mexico Scanner Frequencies and Radio Frequency Reference

Scanner Frequencies and Radio Frequency Reference for New Mexico (NM)

www.radioreference.com

If it's not, you're going to need to do a little digging. It looks like XPT systems might need to be in LCN order. Did you check this?

Mike

Hello, Mike.

Thanks for responding!

That system isn't in the RR database. I found the frequency one day as I drove through town (Espanola, NM) with my BCD325P2 in "Close Call" mode.

You're right about my need to do a little digging. I stopped by the casino last Saturday to see what kind of radios they were using and saw handheld Hyteras clipped to everyone's belts. They looked a lot like Hytera's PD6 series (specifically, the PD602 radio), which seemed to confirm the possibility it was an XPT system, as indicated in the display of my BCD436HP. It's also possible that they're operating in Hytera's "DMO True 2-Slot/DMRA Direct Mode," but I don't think I can confirm that without actually knowing how the radios are programmed (i.e. which slots are assigned to which talkgroups/channels).

All I've heard so far is traffic on one frequency, but I really need to sit out in the parking lot some day and listen for a while longer in "Close Call" mode. Until I find additional frequencies, there's no point in worrying about LCN's. It's too hot out here to sit in the parking lot monitoring the system in "Close Call" mode for a long time, but I will do that when I get a chance.

UPDATE: I unlocked that channel in my SDS100, and I'm listening to the casino's radio traffic right now from here at home (external antenna, 15 miles away). Like the BCD436HP, the SDS100 identifies it as an "XPT" system. Unlike the '436 and the '325, the SDS100 seems to resume scanning when the voice traffic stops, but it's got a fairly lengthy "hang time," and I'm not sure if all this isn't because the SDS100 simply isn't as sensitive to weak signals (like the "beacon"?) as my other two Uniden scanners.

Thanks again for your help!

-Johnnie (KC5IGH)

 

[ka3jjz]

You might want to slap the Analyzer function on the 100 on when the channel is active and see what it tells you...unfortunately that is one option that the 325p doesn't have...Mike

 

[kc5igh]

Is this the system you're trying to hear?

Code 3 Service XPT Trunking System, Various, New Mexico

Code 3 Service XPT Trunking System Profile

www.radioreference.com

Mike

That could be the system, but an FCC frequency/license search indicates it's assigned to a radio sales/service shop out of Santa Fe. Their closest transmitter site is on Tesuque Peak, and I'm pretty certain I'm not hearing any voice traffic from that location. Maybe they used that frequency for a transmitter at the casino in Espanola?

I'll keep looking . . .

Thanks, Mike.

-Johnnie

 

[kc5igh]

You might want to slap the Analyzer function on the 100 on when the channel is active and see what it tells you...unfortunately that is one option that the 325p doesn't have...Mike

Hello again, Mike.

I believe the analyzer function only works on trunked systems. All I've got for this system is one frequency, which seems to work best when I've programmed it as a "conventional" channel (I'm pretty sure I missed some of the traffic in trunked mode that was coming through in conventional mode). I suppose I could try programming it again as a DMR single-channel trunked system and see what happens, but all that will give me is signal strength, decode quality, and system activity.

Nonetheless, I'll give it a try when I have a little more time.

Thanks.

-Johnnie

 

[kc5igh]

Correction:

"It took a while to figure out, but I'm pretty certain that the nearby casino I've been trying to program as a NXDN single-channel, Tier 2, or Tier 3 trunked system is actually a Hytera XPT operation. My BCD436HP is the radio that displayed "XPT" during voice transmissions."

I meant to say "DMR single-channel . . ." in that first line, not "NXDN" single-channel . . . "

Apologies . . .

-Johnnie

 

[ka3jjz]

You could be right - Uniden's lack of any comprehensive documentation is proving to be a royal PITA. Nevertheless, you won't hurt a thing trying it and LCN Finder. Who knows, you might learn something....Mike

 

[Ubbe]

Like the BCD436HP, the SDS100 identifies it as an "XPT" system.

XPT are a trunked system and if you program it as trunked it will not respond to any kind of beacon signaling, only the actual voice calls. You get the same problem of scanning stopping on the idle burst from Cap+ system if you program those as conventional digital, they have to be programmed as trunked.

/Ubbe

 

[ka3jjz]

If you did a FCC license search, didn't it show you - or can't you do - a search to tell you all the frequencies for that license? Even if it's not licensed to the casino, it wouldn't be the first time an unlisted user is accessing a DMR trunk, I'm sure. Or the service shop has an agreement with the casino. Either way there's only 1 true way to find out...Mike

 

[werinshades]

Hello again, Mike.

I believe the analyzer function only works on trunked systems. All I've got for this system is one frequency, which seems to work best when I've programmed it as a "conventional" channel (I'm pretty sure I missed some of the traffic in trunked mode that was coming through in conventional mode). I suppose I could try programming it again as a DMR single-channel trunked system and see what happens, but all that will give me is signal strength, decode quality, and system activity.

Nonetheless, I'll give it a try when I have a little more time.

Thanks.

-Johnnie

This is probabaly the reason you're seeing a long hang time after the transmission ends. The other slot is probabaly the data channel which you won't see if programmed as a One Frequency Trunk system..ID Search will show the active talkgroups.

 

[kc5igh]

You could be right - Uniden's lack of any comprehensive documentation is proving to be a royal PITA. Nevertheless, you won't hurt a thing trying it and LCN Finder. Who knows, you might learn something....Mike

Thanks again, Mike . . . I'll give it a try.

It's been my understanding (perhaps mistakenly) that the LCN finder only works if all the potential frequencies for a trunked system have been programmed into the radio. I don't know what it will do with only one frequency programmed into the radio, but as you say, it won't hurt to try.

-Johnnie

 

[kc5igh]

XPT are a trunked system and if you program it as trunked it will not respond to any kind of beacon signaling, only the actual voice calls. You get the same problem of scanning stopping on the idle burst from Cap+ system if you program those as conventional digital, they have to be programmed as trunked.

/Ubbe

Thanks, Ubbe. I'll experiment a little more with DMR trunked system settings and see what happens.

When I programmed this system earlier in my BCD325P2 (as "MotoTRBO Trunk," not "One-Freq Trunk," if I remember correctly), I identified six talkgroups/channels (102 - security, 103 - unknown, 104 - gaming, 105 - gaming, 106 - housekeeping, and 108 - unknown (Those are my labels; I have no idea what they're actually called). The problem was that I seemed to be missing a lot of traffic compared to what the BCD436HP was hearing on that system while programmed as a "conventional" DMR channel in search mode.

I'll try that again and see if the radio will skip over the "beacon" signal after the voice signals have stopped.

I programmed that frequency again last night in my BCD325P2 as "One-Freq Trunk" and didn't hear anything. I can only hear that station from home when the radios are connected to an external antenna (I only have one external antenna available at the moment), so I wasn't able to compare it to the SDS100, which was programmed as a "conventional" DMR channel and receiving lots of traffic before I disconnected it from the external antenna.

I guess my bottom-line question is: "If this is indeed an XPT system (as my SDS100 and BCD436HP indicate it is), what's the best path to take to program it (MotoTRBO Trunk or One-Freq Trunk) as a trunked system.

Thanks again.

-Johnnie (KC5IGH)

 

[kc5igh]

If you did a FCC license search, didn't it show you - or can't you do - a search to tell you all the frequencies for that license? Even if it's not licensed to the casino, it wouldn't be the first time an unlisted user is accessing a DMR trunk, I'm sure. Or the service shop has an agreement with the casino. Either way there's only 1 true way to find out...Mike

You're right, Mike.

I did run an FCC license search and identified six frequencies, one of which was the 451.475 frequency that's actually in use at the casino. I didn't bother to program them into the radio because the FCC license showed them transmitting from Tesuque Peak, which is about 25 miles away. I'm going to try programming all six of those frequencies in one of my scanners to see what happens. As you said, it won't hurt to try.

As I mentioned to Ubbe earlier in this thread, I guess my bottom-line question is: "If this is indeed an XPT system (as my SDS100 and BCD436HP indicate it is), what's the best path to take to program it as a trunked system, MotoTRBO Trunk or One-Freq Trunk?

It's going to take me a while to try all the options and see which one works best, but this is actually fun for a fanatic like me! In the meantime, programming that frequency as a "conventional" DMR channel seems to be picking up all the traffic out there, with the only problem being that pesky "beacon" signal that tends to keep the radio locked in place.

Thanks again.

-Johnnie (KC5IGH)

 

[kc5igh]

This is probabaly the reason you're seeing a long hang time after the transmission ends. The other slot is probabaly the data channel which you won't see if programmed as a One Frequency Trunk system..ID Search will show the active talkgroups.

I think you're right, werinshades.

I need to do some more testing, but I seemed to be missing a lot of transmissions in trunked mode that I wasn't in conventional mode. I can't be certain about that because I only have one external antenna connection here at home, and I can only listen to that system with one radio at a time because it's about 15 miles away.

Thanks for the advice!

-Johnnie (KC5IGH)

 

[werinshades]

It's going to take me a while to try all the options and see which one works best, but this is actually fun for a fanatic like me! In the meantime, programming that frequency as a "conventional" DMR channel seems to be picking up all the traffic out there, with the only problem being that pesky "beacon" signal that tends to keep the radio locked in place.

Thanks again.

-Johnnie (KC5IGH)

The "beacon signal" you keep mentioning is a MotoTRBO "rest channel", which would lead me to believe that's what you're looking at. Yes, program in all 6 frequencies and run LCN finder to see if the one active frequency shows LCN of 1. If their isn't activity on the other 5 frequencies, you will not get any LCN hits. When your scanner shows "Found 1 of 6", press Enter and save it. You have to make sure scanner is in ID Search (defaults to ID Scan).

 

[kc5igh]

The "beacon signal" you keep mentioning is a MotoTRBO "rest channel", which would lead me to believe that's what you're looking at. Yes, program in all 6 frequencies and run LCN finder to see if the one active frequency shows LCN of 1. If their isn't activity on the other 5 frequencies, you will not get any LCN hits. When your scanner shows "Found 1 of 6", press Enter and save it. You have to make sure scanner is in ID Search (defaults to ID Scan).

Thanks again, werinshades!

That's good advice, and I'll give it a try when I get a chance.

 

[Ubbe]

what's the best path to take to program it (MotoTRBO Trunk or One-Freq Trunk) as a trunked system.

You can start with OneFrequencyTrunked and program all frequencies there. Then for sure you have to hear the conversations if you have enough signal strength. The disadvantage are that you will only hear the conversation as long as it stays on the same frequency. If it jumps to another frequency the scanner will leave the site and system and go to next system.

If it turns out to be a multi channel XPT system it's better to program it as MotoTrbo as the scanner then will follow any calls that jumps between channels, if you have the LCN's correctly figured out, best to do by using LCN Finder. The disadvantage are that you will hear very little or nothing at all if you have the LCN's screwed up. So probably best to start with OFT and enable ID Search.

/Ubbe

 

[KG4KHQ]

This may or may not work, but for a XPT system in my area, I found that the 5 frequencies all had a LCN of 1, so it was like 5 different sites. When I discover a new system, I start with 2 sites, one Confirmed and the other Unconfirmed. I’ll put all the frequencies in the Unconfirmed site and run the LCN finder. As LCN’s are found, I move those frequencies to the Confirmed site. As it ended up, I ended up with all having LCN 1. Your mileage may vary.