BCD436HP/BCD536HP: Hytera DMR XPT question

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kc5igh

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You have a good grasp of what you're doing now, so you'll do your own detective work. Here's a talkgroup programming suggestion...it "appears" they're using Channels 1-16 as most radios have 16 channels available to use. Since you're already text tagging your talkgroups, maybe add the others as "Channel x" until you can identify them. Talkgroups 101-116 are probably available, but not all channels are in use. I'd still leave it in ID Search in case they surprise you one day, but good job on your work, and kudos on your patience.

Thanks for your kind words and advice, werinshades!

I'm running the scanners in ID search mode, but I decided not to label the unknown talkgroup "channels" because that makes their display lettering even smaller than it already is in the SDS100 and BCD436HP. If I label them as "Unknown" or "Channel X," those words will show up on the display in maximum letter size, and the relevant talkgroup id's will shrink down to minuscule letters in the corner of the display. Come to think of it, I think the talkgroup id's in the BCD325P2 will go away completely if I label the channels.

I've got pretty good eyesight and I've enjoyed playing with the SDS100 display options, but my 71-year-old eyes ain't what they used to be, and it's essentially unsafe and impossible for me to try and read the display while I'm driving.

I usually leave the trunked radio systems I monitor in ID search mode, unless I want to focus on one department or channel. Most of those systems undergo periodic updates and changes, and it's easy to miss new, important talkgroups.

I've really appreciated your help, werinshades. You know your stuff!

Thanks again.

-Johnnie (KC5IGH)
 

kc5igh

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No I'm just trying to document this mess - it's someone else who is trying to hear this system...

Hello again, kf3jjz.

I thought I'd take a shot at documenting this "mess" (LOL!). Here's what I have so far:
  • My SDS100 and BCD436HP scanners indicate I'm trying to monitor an XPT system (Hytera DMR Extended Pseudo Trunking).
  • I've detected voice traffic and a sub-audible "beacon" or "rest channel" on only one UHF frequency and one color code (10), so far.
  • I've observed the system employees using Hytera radios.
  • The following settings seem to work best for trunk-tracking purposes:
    • MotoTRBO for the system setting
    • Applying LCN 0 or 1 to the frequency setting
    • Applying color code 10 (there may be other color codes in use)
    • Applying NFM modulation
    • Programming talkgroup id's and labels as they're encountered in order to test true "trunktracking" performance, i.e. the ability to hold and/or lock out individual talkgroups
    • Setting the scanner in "ID search" mode to detect new talkgroup id's
This seems simple enough, but at this stage of my explorations, I'd attach some caveats to this list:
  • As usual, I can't know what I'm NOT hearing with these settings in place. More experimentation will be necessary.
  • I need to conduct a frequency search ("Close Call" most likely) to determine whether or not there are other frequencies and/or color codes in use. I thought I saw color code 8 fly by very briefly at one point, but I'm not certain about that.
  • I need to determine whether or not there's a "real" radio performance difference between LCN 0 and 1. I thought I saw a slight improvement in scanning performance (faster signal detection and less cut-off at the start of transmissions, for example) when I changed the LCN from 1 to 0, but I really can't be sure about that.
  • I'm under the impression that there are many different types of DMR trunked systems out there, and there are therefore many ways to program them. What I've described above is most likely pertinent to this particular system and the relatively low level of traffic it was designed to handle. I don't think this design would work well with significantly more traffic.
I hope this helps, and I'll keep you posted as I work my way through all this.

Thanks.

-Johnnie (KC5IGH)
 

werinshades

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Thanks for your kind words and advice, werinshades!

I'm running the scanners in ID search mode, but I decided not to label the unknown talkgroup "channels" because that makes their display lettering even smaller than it already is in the SDS100 and BCD436HP. If I label them as "Unknown" or "Channel X," those words will show up on the display in maximum letter size, and the relevant talkgroup id's will shrink down to minuscule letters in the corner of the display. Come to think of it, I think the talkgroup id's in the BCD325P2 will go away completely if I label the channels.

I've got pretty good eyesight and I've enjoyed playing with the SDS100 display options, but my 71-year-old eyes ain't what they used to be, and it's essentially unsafe and impossible for me to try and read the display while I'm driving.

I usually leave the trunked radio systems I monitor in ID search mode, unless I want to focus on one department or channel. Most of those systems undergo periodic updates and changes, and it's easy to miss new, important talkgroups.

I've really appreciated your help, werinshades. You know your stuff!

Thanks again

-Johnnie (KC5IGH)

You can edit the display so you can see both Talkgroup and label for it, but whatever works best for you is the optimum set up. Glad I could shed some light on the system programming, and if a couple of locals are listening, you should be able to submit the info for the database shortly. If you can hold on a talkgroup and hear both sides of a conversation, then it's programmed correctly. When the system is busy, run the LCN finder again because activity will trigger an LCN channel assignment.

Happy hunting as they used to say...
 

ka3jjz

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I'm just going to point to this thread in both the 436 and SDS FAQs- far easier that way. It's too good information to lose.

Mike
 

kc5igh

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You can edit the display so you can see both Talkgroup and label for it, but whatever works best for you is the optimum set up. Glad I could shed some light on the system programming, and if a couple of locals are listening, you should be able to submit the info for the database shortly. If you can hold on a talkgroup and hear both sides of a conversation, then it's programmed correctly. When the system is busy, run the LCN finder again because activity will trigger an LCN channel assignment.

Happy hunting as they used to say...
Thanks, werinshades.

I'd forgotten that I could simply add the talkgroup number to the temporary channel label (e.g. SECURITY - TG101) for better visibility.

-Johnnie (KC5IGH)
 

kc5igh

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I'm just going to point to this thread in both the 436 and SDS FAQs- far easier that way. It's too good information to lose.

Mike

Wow, ka3jjz, that's quite an honor!

I'll keep you updated on any significant developments.

The next thing I plan to do is look for any additional frequencies and color codes via Close Call. So far, frequency-range searches from home aren't revealing anything, but a couple of new DMR systems I didn't know existed, and they don't appear to be related at all to the casino traffic.

-Johnnie (KC5IGH)
 

kc5igh

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Greetings:

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

UPDATE:

I've tried conducting "Close Call" frequency searches several times with this system, but I have yet to hear traffic on anything but the single frequency, 451.475.

As I understand it, Hytera's DMR XPT systems rely on one or more repeaters, not the usual centralized controller you find on "real" trunked systems. I think that means there may, or may not, be a second repeater in that system that comes to life only when more than two slots become active. If that's true, I'll only find a second frequency (or more) if and when the system exceeds the capacity of its one-frequency, two-slot repeater.

Please feel free to correct my assumptions.

Thanks!

-Johnnie (KC5IGH)
 

cg

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There is a HOME channel function. A system may have up to 8 repeaters (16 slots). A group of radios are assigned to a repeater acting as the HOME repeater. In the event both slots are busy, the other channels/slots are scanned by those radios and if a call comes through, the radios use the free slot on a different repeater.

chris
 

kc5igh

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There is a HOME channel function. A system may have up to 8 repeaters (16 slots). A group of radios are assigned to a repeater acting as the HOME repeater. In the event both slots are busy, the other channels/slots are scanned by those radios and if a call comes through, the radios use the free slot on a different repeater.

chris

Thanks, Chris, that's how I understand the system works.

It looks like an inexpensive way to set up a small, multi-channel radio system without resorting to a regular trunked system that requires a control channel and multiple input/output frequencies, especially if you or your radio service provider already have a couple of licensed frequencies you can use.

It looks like I'm going to have to wait a while to find out if there's a second repeater available.

-Johnnie (KC5IGH)
 

JASII

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I just ran across this thread and it seems similar enough to my XPT challenges that people here may be able to help.

The system(s) that I am trying to monitor and map out are Professional Wireless Communications (PWC).

There are seven frequencies that I think are part of this. They are:

452.100 (LCN 1) WQWK335 (Minneapolis)

462.375 (LCN 2) WQWK335 (Newport)

463.675 (LCN 3) WQWK335 (Newport)


463.650 (LCN 1) WQWK335 (Minneapolis)

463.800 (LCN 2) WPER836 (Minneapolis)


461.125 (LCN 1) WPER836 (Minneapolis) and WPMH825 (Minneapolis)

462.075 (LCN 2) WPMH825 (Chaska)

They all are using all using Color Code 4.

The next things I am trying to determine is which frequencies are used at which site. I have read that the FCC license data isn't always 100% reliable in this regard.

I have used the LCN Finder function on my Uniden SDS100




I have both Butel ARC536PRO and ProScan and having been checking History Logs to what TGIDs and UIDs are in use.

Hands down, the most activity is on 452.100.

What steps should I take next to maps out these systems?

Would there be much benefit to using the Analyze function?

When I look at the History Log, I see the TGIDs in use. It appears that a given TGID remains on the Home Channel unless there is activity causing it to move elsewhere. Is/are whatever frequency(ies) that are logged with that same TGID necessarily part of that same site or could it show up on another site that is linked?

I know with MOTO TRBO, there are one frequency trunking. Is that possible with Hytera XPT, also?

Finally, with 461.125 licensed under two different callsigns, is it possible that it is apart of two different XPT systems? It is not particularly busy, but could it handle overflow and be a part of two different systems?
 
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