DSDPlus Unusual XPT Talkgroups

[racingfan360]

Hi all, looking for some pointers on what might be going on here:

I'm monitoring a busy XPT Trunked network, Talkgroups in use are 1-50. But I occassonally see 7 digit talkgroups appear, each one would seem to be in multiples of +1,048,576 from the 'real' TG in use. ie I'm seeing the same radio ID's listed on TG1 as TG1048577 TG2097153 TG3145729 TG4194305 TG5242881 and TG6291457. I'm seeing these odd TGs' appear in DSDPlus and on a Whistler TRX1. 1,048,576bytes = 1MB.

Anyone know what's going on here? I assume these 7 digit TG's are false positives. Ive only ever seen this on a XPT Trunked system.

 

[dave3825]

Pretty sure xpt tg's are only 1 to 255. What version of DSDPlus are you running and how is your signal? Can you post a screenshot of fmp spectrum showing an active freq?

Read that Uniden scanners were displaying 7 digit xpt tg's back in 2016. Something with reading hex instead of dec or something like that.

 

[R0am3r]

@dave3825 - I too remember something about reading talk groups incorrectly, but I just can't find the information. A mind is a terrible thing...

Also - According to the Hytera XPT websites, there are 245 groups for communications. This seems like a strange number and makes me wonder if there are 10 groups dedicated to data or control signals? Also note there are 1200 private call groups.

 

[dave3825]

For the x36 scanners, it was @cg who discovered it. DMR Public Release

According to the Hytera XPT websites, there are 245 groups for communications. This seems like a strange number and makes me wonder if there are 10 groups dedicated to data or control signals?

I read something like this.

Radio ID range from 1 to 65535, group ID from 1 to 249, emergency group ID from 250-254, and all call ID is 255.

I think the OP may just be getting a bad decodes every now and again, possibly signal related..

 

[racingfan360]

Thanks for the info guys. I expect this is a combination of bad decodes and some unusual handling of XPT talkgroups.