How to improve NXDN scanning

[troymail]

Monitored a 9600 system today with DSD+ and saw yet another "mode" of operation. This system has 4 channels/ frequencies and a dedicated control channel.

When the 4th user (talkgroup) decides to go active, they took over the control channel for voice (i.e. at least momentarily, there was no control channel).

I *think* as soon as the first (any of the 4) frequenc(ies) became inactive, it (temporarily?) became the control channel.

I also *think* that once the "primary" control channel became active, the control channel switched back to that frequency....

Note that this is in contrast to another system I watched last week - not much activity at all... When a talkgroup became active, voice was heard on the control channel. Once they stopped talking, the control channel returned to the frequency. I can't say for sure if the control channel appeared on another frequency on that system when the voice took over -- something I'll have to watch for next time I am in that area.

Point being - you really don't want to lock out or remove the control channel frequenc(ies)....unless you know the system doesn't do one of these things (or some other form of it).

 

[ve52001]

Hey Sibbley, I do know in my area from talking to the local PD officers that they share the same dispatch channel with 2 others in my area. There are 3 NXDN 9600 systems that they agencies use and they are networked into each other. So that could be what you are hearing is two systems networked together and are transmitting on two different frequencies but in different areas, and you are hearing both. Just a possibility.

 

[sibbley]

Hey Sibbley, I do know in my area from talking to the local PD officers that they share the same dispatch channel with 2 others in my area. There are 3 NXDN 9600 systems that they agencies use and they are networked into each other. So that could be what you are hearing is two systems networked together and are transmitting on two different frequencies but in different areas, and you are hearing both. Just a possibility.

100% sure it was the same business. Same TGID, first frequency was the dispatcher telling the salt/cinder truck which businesses to hit in what order. Second frequency was the salt/cinder truck talking back to the dispatcher. There was only 1 active TGID on the system for the overnight hours. I could literally watch the frequency change as dispatch dropped and the truck replied.

 

[slicerwizard]

Monitored a 9600 system today with DSD+ and saw yet another "mode" of operation. This system has 4 channels/ frequencies and a dedicated control channel.

When the 4th user (talkgroup) decides to go active, they took over the control channel for voice (i.e. at least momentarily, there was no control channel).

I *think* as soon as the first (any of the 4) frequenc(ies) became inactive, it (temporarily?) became the control channel.

I also *think* that once the "primary" control channel became active, the control channel switched back to that frequency....

Note that this is in contrast to another system I watched last week - not much activity at all... When a talkgroup became active, voice was heard on the control channel. Once they stopped talking, the control channel returned to the frequency. I can't say for sure if the control channel appeared on another frequency on that system when the voice took over -- something I'll have to watch for next time I am in that area.

Point being - you really don't want to lock out or remove the control channel frequenc(ies)....unless you know the system doesn't do one of these things (or some other form of it).

Simplest course of action is to just see if composite control channels (voice on control) is part of the site's feature set.

Sync:+NXDN48 TB CCDATA SRV_INFO Category=Local System=2004 Site=6 MultiSite LocnReg GrpReg Auth CompCC Voice Data ShortData Status&RemCtl

 

[ve52001]

I believe these are the same talk groups also. Do you use one of those dongles with your DSD+ software? I might get me one if it is simple to setup. If the info on radio reference is correct, each of these 3 systems I mentioned, the coverage isn't that good. That is why they are using 3 NXDN trunking sites networked together to cover the 3 cities.

 

[sibbley]

Yes, I have 2 RTL-SDR.com dongles. I just sat down tonight with all my gathered info on this system from the past weeks monitoring. I added all the info I should need to make my first attempt at trunk tracking with DSD+ when the system gets active again Monday or Tuesday. It's a strange system. It's fairly busy between 5AM and 3PM. After that it almost completely dies out. There hasn't been any activity since about 2:30PM yesterday!

DSD+ has several text files to help with setup. There are a few threads here on RR to help get setup too. It's not that hard. Takes a little time, that's all. I found most of my local DMR over the last year and a half by simply scanning frequencies with FMP and DSD+.

 

[ve52001]

Yes, I have 2 RTL-SDR.com dongles. I just sat down tonight with all my gathered info on this system from the past weeks monitoring. I added all the info I should need to make my first attempt at trunk tracking with DSD+ when the system gets active again Monday or Tuesday. It's a strange system. It's fairly busy between 5AM and 3PM. After that it almost completely dies out. There hasn't been any activity since about 2:30PM yesterday!

DSD+ has several text files to help with setup. There are a few threads here on RR to help get setup too. It's not that hard. Takes a little time, that's all. I found most of my local DMR over the last year and a half by simply scanning frequencies with FMP and DSD+.

Do I need 2 dongles to use with DSD+? I'm thinking about getting them, but not sure if I wanna even try using my slow windows laptop for it. I have a Imac, but not everything works with mac os.

 

[sibbley]

Do I need 2 dongles to use with DSD+? I'm thinking about getting them, but not sure if I wanna even try using my slow windows laptop for it. I have a Imac, but not everything works with mac os.

If you want to trunk track you need either a taped scanner and a dongle or 2 dongles. If you just want to slowly scan a list of frequencies you only need 1 dongle. Or with a taped scanner you can run the audio through DSD+ and decode.

 

[ve52001]

Ok, thanks for the info. I might wait and see how the NXDN 9600 works out with the TRX scanners. I talked to someone in this area that has tried but getting nothing on the NXDN 9600 system on his TRX 1 scanner, but able to decode a 4800 system. Hopefully Whistler releases a fix, or Uniden comes out with a update to do NXDN. Either way I'm eventually going to buy a new scanner, I currently only have a PSR 600.

 

[ve52001]

I was just curious if anyone has heard back from Whistler about the NXDN issues with 9600 systems?

 

[W4KRR]

I was just curious if anyone has heard back from Whistler about the NXDN issues with 9600 systems?

Not specifically the 9600 systems, but when I emailed a bug report to Whistler about the NXDN issues in general, they responded that they were aware of the issues and that a firmware update would be coming "shortly".

 

[hiegtx]

Not specifically the 9600 systems, but when I emailed a bug report to Whistler about the NXDN issues in general, they responded that they were aware of the issues and that a firmware update would be coming "shortly".

That's good news. For one of the local systems, used by three small suburbs in Dallas County, I'm having no success at all monitoring them other than by doing a limit search on the site frequencies. Other than an occasional 'data' hit, I get nothing on any of the three sites of this system. That's when programmed as indicated on the database page, or using the other variants of NXDN in the scanner, including scanning the frequencies conventionally. I am well within range.

 

[KevinC]

To support Justin's theory of no trunk tracking try this...

Start the Whistler "Control Demo" application, wait for a TG to become active and pause on that TG. Watch the "Frequency" box and I bet it continues to sweep through all the frequencies you have in that system. This needs to done on a dedicated CC NXDN system.

I can confirm on Connect Plus it behaves this way as opposed to P25 trunked system where it will stay on the CC until a VC grant. I don't have a TRX-1/2 to test NXDN.

And sorry if someone already suggested this and I missed it.

Jeff at The Ham Station sent me a TRX-1 and 2 to play with.

Probably not earth shattering news, but I can confirm that when you pause on a TG it continually scans the other programmed frequencies looking for a match. So it is not using the CC for it's information.

 

[ron_tn]

NXDN

I know nothing about programing. I have aTRX-2 and live in Sevierville,Tn I have no problem receviving police dispatch. there are bugs but they are working on them

 

[daredevil1]

A firmware update was issued. My scanner audio no longer breaks up.

 

[edemtp]

TRX-1 question

Hope all is OK to jump in here. Thinking of buying the scanner. I am a Amateur Radio operator. The scenario I have here is NXDN trunked with the Sheriff Dept encrypting about 5 frequencies. Not worried about listening to the Sheriff or the trunking following. Can I program the scanner with the conventional frequencies and lock out the Sheriff talkgroup where the scanner will not hang on their encrypted transmission. Thanks, Ed

 

[troymail]

Conventionally, I believe you can only program in specific talkgroups to RECEIVE. So, if you know which you want to HEAR and which ones you don't, you can do that. You'd just need to program those to hear as a conventional channel (one per talkgroup).

If you also want to search for new talkgroups using conventional programming (you can) but in that mode, you won't be able to tell the radio (in that mode) to ignore certain talkgroups.... that is a function of trunk system programming.

 

[AggieCon]

EDIT: This is wrong. See next post.

You should be able to ignore the encrypted talkgroup with the NXDN programmed on the conventional frequency tab.

Create one set of objects for each frequency that accepts all talkgroups.

Create a second set of objects for each frequency that specifies the offending talkgroup. Enable "Lockout" for each of these.

I haven't personally tested this, but I will try to soon.

The benefit of programed conventionally, for simple programing criteria is that the scanner scans more rapidly than if it is configured as a trunked system. The scanner does not trunk track NXDN, so the biggest benefit of programming as a trunked system is to simplify user programming when there are a large amount of talkgroups (for each talkgroup, you make just one entry for the entire set of frequencies rather than an entry for each individual frequency). Also, it is my assertion that, at least initially, when programmed as trunked systems, the radio would hang on the control channels of some NXDN systems.

 

[AggieCon]

I was wrong in the post above. Conventional objects are independent and do not affect one another. So the only way to select specific NXDN talkgroups, when programmed conventionally, is positively (i.e. list either a wildcard or each talkgroup that you want to hear). You can't lock them out.

See the following from DonS: http://forums.radioreference.com/wh...-difference-between-l-o-skip.html#post2725368

"CONV objects are completely independent of each other. Locking out one CONV object has no effect on any other CONV object."

 

[KT4DLB]

Problems with NXDN programming on Whistler WS 1065

I have tried to program all the frequencies excluding the control and the alternate frequencies in the scanner as conventional and not as a talk group. I get a loud roaring noise from all the frequencies. I can turn the squelch from about 10 to 0 to try and stop it and it don't. Can someone please tell me what I'm doing wrong.