NXDN

[mam1081]

I found some NXDN being used yesterday! It was on a BNSF line between Clovis, NM and Amarillo, TX - sounded like intra-train comms. It was on 160.290 using a RAN of 1. NX48 - decoded on a TRX-1 and a BCD536HP.

 

[chief21]

Here's a turn-around... Last week, my wife and I rode the Great Smoky Mountain Railroad (GSMRR) in North Carolina. During the trip, I monitored their Road channel (which used NXDN), but their yard and switching channels are listed in RR as using analog, but I didn't hear any traffic at all on those channels. Of course, this line is somewhat isolated and I don't think that any other lines are using the GSMRR tracks.

 

[gary123]

Question. I have a NXDN Kenwood comming from Ebay. can I program it up to monitor the NXDN rail frequencies? I have the software and cables. I am about a half mile from the yard and can hear the data rock solid.

 

[Nasby]

Question. I have a NXDN Kenwood comming from Ebay. can I program it up to monitor the NXDN rail frequencies? I have the software and cables. I am about a half mile from the yard and can hear the data rock solid.

Sure can.
As long as you know what you're doing and have the proper software, cable, etc.

 

[INDY72]

And program ALL TX Inhibited, remove the PTT button or tape over it so thick it can never work again... You will need the RAN, the TGs in use....

 

[kayn1n32008]

And program ALL TX Inhibited, remove the PTT button or tape over it so thick it can never work again... You will need the RAN, the TGs in use....

Or just blank out the transmit frequency. It will not transmit. These are not hammy toy radios. There is no need to tape over or remove the PTT.

There are no talk groups used in conventional NXDN, you should only need the RAN in use


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[gary123]

Great news.I am using a NX800 and have the current software and cable. I will verify the freq, RAN and TG used. I had already planned on leaving the TX side blank so the unit could never TX.

 

[kayn1n32008]

Great news.I am using a NX800 and have the current software and cable. I will verify the freq, RAN and TG used. I had already planned on leaving the TX side blank so the unit could never TX.

Pretty sure conventional NXDN does not use talkgroups(at least that I could find)




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[nickwilson159]

Great news.I am using a NX800 and have the current software and cable. I will verify the freq, RAN and TG used. I had already planned on leaving the TX side blank so the unit could never TX.

It's an NX-800, not an NX-700? NX-800s cover UHF, whereas railroad voice comms are on VHF...

 

[gary123]

sorry I have both a VHF and a UHF NX mobile.

I loaded in the freq and the RAN and have no troubles RX ing the rail yard. I can confirm I did not see any setting for entering in a TG.

 

[RadioDitch]

Pretty sure conventional NXDN does not use talkgroups(at least that I could find)

If programmed as a one frequency trunked system it can, and there agencies doing such. However, the AAR Protocol as agreed is for all NXDN conventional.

 

[kayn1n32008]

If programmed as a one frequency trunked system it can, and there agencies doing such. However, the AAR Protocol as agreed is for all NXDN conventional.

You would need a system key to program a NXDN system into a NX subscriber though.


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[RadioDitch]

You would need a system key to program a NXDN system into a NX subscriber though.

You would need a system key to program any trunked system into any Icom, Kenwood, or Motorola radio using any protocol. Thankfully, that isn't an issue with the AAR Plan being conventional.

 

[kayn1n32008]

You would need a system key to program any trunked system into any Icom, Kenwood, or Motorola radio using any protocol. Thankfully, that isn't an issue with the AAR Plan being conventional.

And again, conventional NXDN does not use talkgroups.

There is little point in programming a 1 channel NXDN trunk system. It’s pointless.


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[RadioDitch]

And again, conventional NXDN does not use talkgroups.

There is little point in programming a 1 channel NXDN trunk system. It’s pointless.


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Right.........

Think you should re-read my original reply. I think you're misunderstanding what I wrote.

 

[N9JIG]

I am not real familiar with how NXDN works vs. P25, but in P25 conventional systems such as Chicago FD they have single channels that use trunking style radio ID's and supposedly other features. While not truly trunking, on Uniden scanners you program them in as Single Channel Trunked to view radio ID's.



Could similar technology be used on NXDN single channel systems? Could separate talkgroups be used to provide a PL type function on conventional NXDN channels? Would programming as such provide the decode of radio ID's etc.?


IIRC DMR does stuff like this as well, but that might be more related to time slots.

 

[INDY72]

Yes on conventional NXDN, and iDAS radio systems you can indeed set up TG for EVEN MORE control of users on your system. There ARE some LEAs etc using this on NXDN conventional systems. Its more common actually than real use this way on P25. As far as I know on P25 Conventional you only have like 2 TGs such as 1, and 2? But also, from what I see in use by CSX here in Indy, they do not have this set up on the VHF AAR freqs. It is used on one of the UHF repeaters for local ops. And is also going to soon be in use at the Amtrak Repair facility here in Beech Grove on the UHF repeaters. Unknown as to if they will do this on the VHF AAR repeater.

 

[mikewazowski]

As far as I know on P25 Conventional you only have like 2 TGs such as 1, and 2?

You can have as many talkgroups as you want. Take a look at the p25nx network for an idea of talkgroup usage on P25 conventional.

 

[kayn1n32008]

Edit. Never mind. Figured it out.


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[INDY72]

(IIRC DMR does stuff like this as well, but that might be more related to time slots.)

DMR uses multiple TGs as well as the 2 Time Slots on conventional to create some rather large systems using small frequency assignments. Add in IP Site Connectivity and you can have pretty much a good sized network that is very nearly trunking. Hypothetical Example: You have lets say an three site IP SC set up to cover your small local excursion railway. The DMR portion is used on your private railroad section, and you also have the analog AAR (For now as that will change in the future) in your radios for transit on an mainline Class I RR to say an storage track etc somewhere off site. Your three repeaters use 160.0125 at all 3 sites for the main ops, 161.4275 at one location for your lets say rail museum ops... And 161.3275 at the shop ... 160.1275 at central site for lets say, Security etc...

You have 2 Slots on each freq. Lets say on the main rail freq... You have TG 1 for Dispatcher, TG 2 for Road on Slot 1, TG 3 for MOW, and TG 4 Yard Ops on Slot 2... This is for all 3 sites. All in all you have at least 10 to 12 available talk paths... And so on. NXDN is only 1 available talk path, but can have multiple users broken into TGs like on P25. (Though not being done yet that we know of on AAR freqs as the sharing of the freqs to that depth would be problematic in the rail world on busier systems.)