What are these data blips in the 220-222 MHz former HAM range?

[IC-R20]

I regularly get these blips in the 220 range, usually more spread out between this range pictured but when I took the screenshot today they were more concentrated for some reason. I don't live in a big city or anywhere with 217 MHz TRS type stuff though I do remember glancing over something before about railroads using this range and I do live next to very active BNSF track, The Southern Transcon (Seligman Subdivision).

They look somewhat similar on waterfall to what I get from the 900 MHz ISM Itron power meters and some part 15 stuff in 433.92.

 

[nd5y]

If you are in the US and near a railroad it is probably PTC.

 

[Ace9133uwu]

What ND5Y said, it’s definitely PTC. PTC freq’s sit between 217.0125 & 221.29375MHz.

 

[IC-R20]

What ND5Y said, it’s definitely PTC. PTC freq’s sit between 217.0125 & 221.29375MHz.

Neat, I'll have to get a USB C OTG cable and try running SDR Touch closer to the rails sometime and see how many more I pick up. Do these bursts stay on an assigned channel or are they frequency agile?

 

[Saint]

I was wondering the same thing, is there a way to decode these signals. ?????
Saint

 

[nd5y]

Do these bursts stay on an assigned channel or are they frequency agile?

The ones near me appear to be on the same few channels but I never paid close attention to it and don't have a SDR or other way to look at the whole band at the same time.

The list of frequencies is at the bottom of the page. I don't know how accurate it is. PTC doesn't have site-based licensing like the 160 MHz railroad channels.

Railroads (United States) Scanner Frequencies and Radio Frequency Reference

Scanner Frequencies and Radio Frequency Reference for Railroads (United States)

www.radioreference.com

 

[Ace9133uwu]

Neat, I'll have to get a USB C OTG cable and try running SDR Touch closer to the rails sometime and see how many more I pick up. Do these bursts stay on an assigned channel or are they frequency

I was wondering the same thing, is there a way to decode these signals. ?????
Saint

I can say there definitely is a way. I’ve heard of railfans and general radio listeners decoding with SDR. However I’ve never attempted it nor really have the desire to.

 

[Saint]

I can say there definitely is a way. I’ve heard of railfans and general radio listeners decoding with SDR. However I’ve never attempted it nor really have the desire to.

Thanks for the information, I was just wondering if it could be decoded.
Steve

 

[kruser]

I can say there definitely is a way. I’ve heard of railfans and general radio listeners decoding with SDR. However I’ve never attempted it nor really have the desire to.

You won't decode the 220 MHz PTC data. It's encrypted. What is not known yet is if the ITCM (old ATCS) protocol is encrypted or not now that most railroads are moving their ATCS data to ride along with the 220 MHz PTC signal.
You can decode the EOT, HOT and DPU signals in the 452/457.xxx range but not much data is contained in their signals. The existing ATCS data in the 900 MHz range can also be decoded but most railroads are abandoning that frequency range for ATCS and moving it onto the PTC data range in the 220 MHz band. Some railroads will keep using the new 900 MHz frequencies for ATCS data but most are moving away from the band.
The FCC is realigning the part of the 900 MHz band that railroads have been using for ATCS control and signalling for internet data which may require new radios or at the least, the reprogramming of existing radios that have the capability. Most sizable railroads are taking advantage of this and moving everything other than the 160/161.xxx MHz voice channels to the 220 MHz PTC frequencies
BNSF has always used the 160 MHz railroad band for their ARES (similar to ATCS) signal and control data channel but they are now also moving that data over to the 220 MHz PTC data channels as PTC is mandated by the AAR for most sizable railroads. This allows the railroads to only need to maintain one radio network for data and eliminate the 900.xxx radios and equipment. Of course they will still use the 160.xxx MHz railroad frequencies for voice comms which will eventually switch to NXDN digital. Some of the simple voice comms RR monitoring railfans heard in the past are now being sent over PTC which is then displayed on data terminals instead of using voice. This will reduce the amount of actual voice traffic in the 160.xxx band and make it a bit harder for railfans to monitor trains.
And who knows if the 452/457.xxx MHz EOT, HOT and DPU frequencies and equipment will stay as is but I suspect it will remain as it is today for some time.

 

[Saint]

You won't decode the 220 MHz PTC data. It's encrypted. What is not known yet is if the ITCM (old ATCS) protocol is encrypted or not now that most railroads are moving their ATCS data to ride along with the 220 MHz PTC signal.
You can decode the EOT, HOT and DPU signals in the 452/457.xxx range but not much data is contained in their signals. The existing ATCS data in the 900 MHz range can also be decoded but most railroads are abandoning that frequency range for ATCS and moving it onto the PTC data range in the 220 MHz band. Some railroads will keep using the new 900 MHz frequencies for ATCS data but most are moving away from the band.
The FCC is realigning the part of the 900 MHz band that railroads have been using for ATCS control and signalling for internet data which may require new radios or at the least, the reprogramming of existing radios that have the capability. Most sizable railroads are taking advantage of this and moving everything other than the 160/161.xxx MHz voice channels to the 220 MHz PTC frequencies
BNSF has always used the 160 MHz railroad band for their ARES (similar to ATCS) signal and control data channel but they are now also moving that data over to the 220 MHz PTC data channels as PTC is mandated by the AAR for most sizable railroads. This allows the railroads to only need to maintain one radio network for data and eliminate the 900.xxx radios and equipment. Of course they will still use the 160.xxx MHz railroad frequencies for voice comms which will eventually switch to NXDN digital. Some of the simple voice comms RR monitoring railfans heard in the past are now being sent over PTC which is then displayed on data terminals instead of using voice. This will reduce the amount of actual voice traffic in the 160.xxx band and make it a bit harder for railfans to monitor trains.
And who knows if the 452/457.xxx MHz EOT, HOT and DPU frequencies and equipment will stay as is but I suspect it will remain as it is today for some time.

Thanks for all the information.
Steve

 

[Ace9133uwu]

You won't decode the 220 MHz PTC data. It's encrypted. What is not known yet is if the ITCM (old ATCS) protocol is encrypted or not now that most railroads are moving their ATCS data to ride along with the 220 MHz PTC signal.
You can decode the EOT, HOT and DPU signals in the 452/457.xxx range but not much data is contained in their signals. The existing ATCS data in the 900 MHz range can also be decoded but most railroads are abandoning that frequency range for ATCS and moving it onto the PTC data range in the 220 MHz band. Some railroads will keep using the new 900 MHz frequencies for ATCS data but most are moving away from the band.
The FCC is realigning the part of the 900 MHz band that railroads have been using for ATCS control and signalling for internet data which may require new radios or at the least, the reprogramming of existing radios that have the capability. Most sizable railroads are taking advantage of this and moving everything other than the 160/161.xxx MHz voice channels to the 220 MHz PTC frequencies
BNSF has always used the 160 MHz railroad band for their ARES (similar to ATCS) signal and control data channel but they are now also moving that data over to the 220 MHz PTC data channels as PTC is mandated by the AAR for most sizable railroads. This allows the railroads to only need to maintain one radio network for data and eliminate the 900.xxx radios and equipment. Of course they will still use the 160.xxx MHz railroad frequencies for voice comms which will eventually switch to NXDN digital. Some of the simple voice comms RR monitoring railfans heard in the past are now being sent over PTC which is then displayed on data terminals instead of using voice. This will reduce the amount of actual voice traffic in the 160.xxx band and make it a bit harder for railfans to monitor trains.
And who knows if the 452/457.xxx MHz EOT, HOT and DPU frequencies and equipment will stay as is but I suspect it will remain as it is today for some time.

Awesome, thanks for all the information. I swear I read someone decoded PTC. But it is the internet- you can’t believe everything. However I’ll take your word for it 100% since what I read is likely buried in the depths of internet purgatory. That said, I definitely knew that HOTD/EOTD, DPU & “legacy” ATCS can be decoded. Still a shame that class 1’s are abandoning the old tech. How fast the world we live in moves, huh? When I learned that CSX abandoned legacy ATCS for satellite based operations just about blew me down.

Regarding the age-old debate of class 1’s and system wide implementation and usage of NXDN, personally I feel like that’s still a long way off. Even though the class 1’s are absolute conglomerations, they likely won’t pony up the potential millions of dollars to upgrade every locomotive radio, hi-rail radio and employee HT. Railfans need not worry- yet. But I’ve still invested in an NXDN upgrade for my scanner juuust in case.

 

[kruser]

Awesome, thanks for all the information. I swear I read someone decoded PTC. But it is the internet- you can’t believe everything. However I’ll take your word for it 100% since what I read is likely buried in the depths of internet purgatory. That said, I definitely knew that HOTD/EOTD, DPU & “legacy” ATCS can be decoded. Still a shame that class 1’s are abandoning the old tech. How fast the world we live in moves, huh? When I learned that CSX abandoned legacy ATCS for satellite based operations just about blew me down.

Regarding the age-old debate of class 1’s and system wide implementation and usage of NXDN, personally I feel like that’s still a long way off. Even though the class 1’s are absolute conglomerations, they likely won’t pony up the potential millions of dollars to upgrade every locomotive radio, hi-rail radio and employee HT. Railfans need not worry- yet. But I’ve still invested in an NXDN upgrade for my scanner juuust in case.

I guess anything's possible!
I wonder if someone decoded it in its early testing days.
I myself will miss ATCS as I do use the program to monitor activity on the UP and BNSF subs near me. It's kinda fun to watch!

And I agree that switching to NXDN is a ways off. I've only heard I think NS using NXDN on a known yard channel but they were only testing. I've never heard another NXDN signal on any of the standard AAR VHF channels but I do have radios that will decode narrow and very narrow flavors of NXDN if they do switch.
Someone in my range is using DMR on 161.565. The decode is bad here though as the signal is not very strong. I've yet to figure out who it is. I think I recall searching and found that NS is the main license holder for 161.565 near me. It appears maybe at one of the many yards over in Illinois across the river from St. Louis. There's a ton of large rail yards on the Illinois side of the Mississippi river. Many are out of range for me though as I'm located in west St Louis county which is a ways from the rail yards in Illinois.

 

[IC-R20]

Awesome, thanks for all the information. I swear I read someone decoded PTC. But it is the internet- you can’t believe everything. However I’ll take your word for it 100% since what I read is likely buried in the depths of internet purgatory. That said, I definitely knew that HOTD/EOTD, DPU & “legacy” ATCS can be decoded. Still a shame that class 1’s are abandoning the old tech. How fast the world we live in moves, huh? When I learned that CSX abandoned legacy ATCS for satellite based operations just about blew me down.

Regarding the age-old debate of class 1’s and system wide implementation and usage of NXDN, personally I feel like that’s still a long way off. Even though the class 1’s are absolute conglomerations, they likely won’t pony up the potential millions of dollars to upgrade every locomotive radio, hi-rail radio and employee HT. Railfans need not worry- yet. But I’ve still invested in an NXDN upgrade for my scanner juuust in case.

I looked it up and have found a couple posts on here and reddit of some SDR programmers saying they did it but there's nothing really publicly general released for it. But yeah it definitely can be done if you know how to code.

 

[merlin]

Multi Psk will decode about anything, weather you get some inteligent data or not, I don't know.
I don't know why they would encrypt PTC, but their call.

 

[WB5ITT]

216-220 is NFM trunked and conventional..and also some amateur packet use via coordination with ARRL and other LMR groups..as well as PTC

 

[Spleen]

There was supposed to be some sort of TED-like talk about it at at GNU convention last year--at the last minute, they cancelled the talk and the release of the code they'd put together to decode PTC...oh well...

From Signal ID Wiki...

 

[BinaryMode]

Here's some interesting information: Positive train control - Wikipedia