SC DOT Possibly Switched to NXDN

[Will001]

Today, 5-18-2023, I tuned my scanner to the Lexington SCDOT VHF lowband repeater (47.200), which I haven't listened to in a while. I then began receiving what I believe to be NXDN data, which I am going to try and confirm later with my digital scanner (when traffic picks up tomorrow during daylight hours). I checked the FCC license for this and several other repeaters around the state, and it looks like they're licensed for NXDN now. Has anyone else heard anything on their local SCDOT repeater? I am going to listen and submit any new info I find to the DB.

 

[Cameron314]

Can't say I know of a low band NXDN repeater.

 

[mmckenna]

It would be surprising (and kind of cool) if they are using NXDN on low band.

As for NXDN low band repeaters, Comtronix has one and I was talking to them at a trade show a year or so ago. I don't see it on their website currently:

Products – Comtronix Communications

www.comtronixcommunications.com

Post 22 on this thread has some more details on it:

P25 Low Band?

How much juice does it put out on low band? I have several amps that are wideband 30-520MHz but they measure the incoming frequency and select a -70dBc low pass filter. These amps take in roughly 1 to 5 watts and put out between 18 and 40w depending on model and operating voltage. I think it's...

forums.radioreference.com

There is a company out of France that sells a DMR type product that works on low band. It had FCC certification last time I looked, but not sure anyone is using them over here, yet.

Might be just data….

 

[mlindler]

Low band digital would be awesome. I've listened to TN National Guard on 30MHZ P25 and it sounded amazing here in SC. Keep us posted on the NXDN!

 

[Cameron314]

It would be surprising (and kind of cool) if they are using NXDN on low band.

As for NXDN low band repeaters, Comtronix has one and I was talking to them at a trade show a year or so ago. I don't see it on their website currently:

Products – Comtronix Communications

www.comtronixcommunications.com

Post 22 on this thread has some more details on it:

P25 Low Band?

How much juice does it put out on low band? I have several amps that are wideband 30-520MHz but they measure the incoming frequency and select a -70dBc low pass filter. These amps take in roughly 1 to 5 watts and put out between 18 and 40w depending on model and operating voltage. I think it's...

forums.radioreference.com

There is a company out of France that sells a DMR type product that works on low band. It had FCC certification last time I looked, but not sure anyone is using them over here, yet.

Might be just data….

Yeah I recall that thread. Is any of it really produced?

It would seem very odd that they will replace all their repeaters and buy all new subscriber which would have to be NX-5600 I would think when they pretty much have a state wide p25 system. Much more cost effective to buy new lower tier 800mhz subscribers then to basically build a new network with radios I'm not sure you can even get.

 

[mmckenna]

Yeah I recall that thread. Is any of it really produced?

It would seem very odd that they will replace all their repeaters and buy all new subscriber which would have to be NX-5600 I would think when they pretty much have a state wide p25 system. Much more cost effective to buy new lower tier 800mhz subscribers then to basically build a new network with radios I'm not sure you can even get.

Don't know. They had one on display and said they'd been trialing it with CHP. In 6.25KHz mode, it apparently worked well, better than analog. Haven't heard any more about it, and they don't say much on their website.

I don't know any commercial LMR products that support P25 on low band. There are military products, but I doubt they are running that. The Harris XL-200M mobiles will do low band, but not sure they'll do P25, and there's an integration piece missing with the low band amplifier that hasn't been released yet.

TPL Systems makes some nice eDMR products that will run on low band. eDMR is a 2 slot TDMA system with a third 'slot' for slow speed data. Nice thing was that they had some unique radios that did analog also, as well as portables (not that hand held low band works well). When I checked, several of them did have FCC Part 90 certification.

TPL Systèmes

TPL Systèmes est un des leaders français dans la conception et la fabrication d'équipements et de solutions de radiocommunication.

tplsystemes.com

Again, would be cool if someone was running digital voice on low band in a commercial application. Would also be some pretty good sized news, and I don't think I've heard of anyone really doing that on any big scale here in the USA.

 

[brian]

It would seem very odd that they will replace all their repeaters and buy all new subscriber which would have to be NX-5600 I would think when they pretty much have a state wide p25 system. Much more cost effective to buy new lower tier 800mhz subscribers then to basically build a new network with radios I'm not sure you can even get.

Don't forget or underestimate the cost of monthly subscription/service cost per radio for Palmetto 800. It's prohibitive for for quite a few smaller county and local governments, and some have decided to use commercial LMR providers in lieu of Palmetto 800. It could be very expensive for SCDOT assuming they have radios in most if not all of their vehicles.

On the other hand, SCDOT has hundreds of millions of "new" tax money now thanks to the increased gas tax from 6 years ago. They have to spend it on something, right?

 

[Cameron314]

Don't know. They had one on display and said they'd been trialing it with CHP. In 6.25KHz mode, it apparently worked well, better than analog. Haven't heard any more about it, and they don't say much on their website.

I don't know any commercial LMR products that support P25 on low band. There are military products, but I doubt they are running that. The Harris XL-200M mobiles will do low band, but not sure they'll do P25, and there's an integration piece missing with the low band amplifier that hasn't been released yet.

TPL Systems makes some nice eDMR products that will run on low band. eDMR is a 2 slot TDMA system with a third 'slot' for slow speed data. Nice thing was that they had some unique radios that did analog also, as well as portables (not that hand held low band works well). When I checked, several of them did have FCC Part 90 certification.

TPL Systèmes

TPL Systèmes est un des leaders français dans la conception et la fabrication d'équipements et de solutions de radiocommunication.

tplsystemes.com

Again, would be cool if someone was running digital voice on low band in a commercial application. Would also be some pretty good sized news, and I don't think I've heard of anyone really doing that on any big scale here in the USA.

I'm not suggesting that they do P25 on a new low band system but that they would use the existing statewide 800mhz system which is P25.

 

[brian]

I'm not suggesting that they do P25 on a new low band system but that they would use the existing statewide 800mhz system which is P25.

I'm not suggesting that either. I was simply pointing out why they may choose to operate their own, proprietary system on low band instead of transitional all of their radio operations to Palmetto 800. There are costs beyond the costs of the radios themselves that may make Palmetto 800 unfeasible. Running their own system without monthly service costs might make more sense. But some might consider such an economically sensible decision out of character for SCDOT.

 

[mmckenna]

I'm not suggesting that either. I was simply pointing out why they may choose to operate their own, proprietary system on low band instead of transitional all of their radio operations to Palmetto 800. There are costs beyond the costs of the radios themselves that may make Palmetto 800 unfeasible. Running their own system without monthly service costs might make more sense. But some might consider such an economically sensible decision out of character for SCDOT.

Exactly. I've worked through the same issues here at work.
Traditional IT types see OpEx (Operational Expenditures) easier to do than CapEx (Capital Expenditures).

In other words, I only have to pay $30/month per radio! That looks good on the annual budget.(OpEx) Similar things done with "subscription services".

Traditional radio types will look at it as "I can build out a radio system for $5 million, and that system will last 10-15 years" (CapEx)

Which one is right? It depends on what side of the IT fence you are on...

 

[2154]

I'll confirm neither the XG-100 nor the XL-200 mobiles will do P25 on low band. LPA or not.

 

[rescuecomm]

SC DOT might require statewide PAL P25 coverage on their truck radios. I couldn't Google up the numbers, but it used to be over $120 per month per unit.

Back before Phase 2 was put in, there was a restriction on certain talkgroups in the coastal area if a hurricane was approaching. I suppose SC National Guard and other EM radio traffic would load the system. Mostly car to car and private TGs not to be used. Maybe SC DOT likes control of their own comms?

About 3 years ago I had a conversation with some SC DOT and SC Forestry radio technicians on 146.520 while traveling I20 east out of Columbia. Interesting guys.

 

[garys]

I hope this is sorted out before my road trip to SC late next month. I'd get a kick out of listening to a low band NXDN system.

 

[rescuecomm]

I hope their existing radios are more up to date than the HP GE stuff sold off years ago. I've got one of those partially installed in my old 1995 Bronco before engine problems sidelined that project. Some hams got a pallet full for next to nothing at the state auction, but everyone had to pay for a PROM to get 6 meter freqs and a tune up ($25).

If they are planning a system change out, then those radios are probably ancient.