VDL2 Ground Stations

[DaveNF2G]

I think the problem in the conversation here is that some are conflating ground station location with terminal ID. Ground stations are just convenient entry nodes to the network and their selection is location dependent. Terminals are the intended destinations of the messages and would have operational significance.

 

[AirScan]

Eric,

I was able to get ground stationt info for KBED. I plan on going up to southern NH soon, so maybe I can get KMHT.

Thanks for posting that, I'd be interested in seeing what you can find in MHT.

Dave,

I rechecked my MultiPSK QSO file and the frequency logged was 136.650 MHz during the entire session.

Somethings not right ? I've checked 3 independent locations with coverage that overlaps the ALB area and not getting anything on 136.650.

Terminals are the intended destinations of the messages and would have operational significance.

Can you give an example of one of these "Terminal ID's" from a VDL2 message ? I'm still not clear on what you mean ?

AS

 

[kma371]

Was able to get to a high level site today and picked up several ground stations throughout the SF Bay Area and Sacramento areas. Those confirmed were added to the wiki.

 

[DaveNF2G]

Can you give an example of one of these "Terminal ID's" from a VDL2 message ? I'm still not clear on what you mean ?

AS

Terminal IDs are the hex numbers that everybody is trying to associate with a particular location.

Ground stations are radio sites operating on 136.975 and/or 136.650 and are fungible.

 

[EricCottrell]

Hello,

I drove up to HRO in Salem NH yesterday and took a side trip to KMHT even with the stormy weather.

1014CA (Ground station, On ground) -> FFFFFF (Aircraft): Command
AVLC: type: U (XID) P/F: 0
XID: Ground Station Information Frame
Public params:
 Parameter set ID: 8885:1993
 Procedure classes: 00 01
 HDLC options: 20 84 80
 N1-downlink: 07 d8
 N1-uplink: 07 d8
VDL params:
 Parameter set ID: V
 AVLC specific options: 20
 Airport coverage: KMHT
 ATN router NETs: 00 00 00 00 00 00	"......"
 System mask: fc 02 00 00
 Ground station location: 42.9N 71.4W

73 Eric

 

[ATCTech]

Should anyone desire to get into the actual technical details, the following ICAO document explains the network layers and frame descriptions for VDL. Pay particular attention to GSIF (ground station information frames) and what they do and what they contain.

https://www.icao.int/safety/acp/Inactive working groups library/AMCP 4/item-3d.pdf

 

[EricCottrell]

Hello,

One project I worked on this weekend is creating a FCC database using mysql from the .DAT files and doing a query on Emission Types. I did something similar using the Canadian files. I ended up with FCC and Canadian ACARS/VDL2 license information. It is likely not complete due to database errors, but it is a start.

I took the information and played with Google Earth to where VDL2 ground stations are located. Very interesting to see how congested the New York City area is. I only populated the Northeast US and Eastern Canada. I need to write some scripts to properly process this.

I included my test files. The hex symbol is used for ARINC and the diamond symbol is used for SITA. You may have to zoom in to see all the sites at the airport.

73 Eric

 

[ATCTech]

That's very handy Eric, thank you!

 

[DaveNF2G]

Yes, thanks for the reference. One of my pet peeves is misuse of nomenclature and, if I have been guilty of that here, then this reference should straighten me out.

 

[AirScan]

Eric,

I drove up to HRO in Salem NH yesterday and took a side trip to KMHT

Thanks for posting the KMHT GSIF, and the database info.

Dave,

Terminal IDs are the hex numbers that everybody is trying to associate with a particular location. Ground stations are radio sites operating on 136.975 and/or 136.650 and are fungible.

Those are the same thing. Those "hex numbers" identify the Ground Station (radio sites).

What do you mean by fungible ? AFAIK there has been no observed active traffic on 136.650 from an aircraft that would be in range of your location (I've checked multiple sources). Those flights you posted earlier were all on 136.975 (dumpvdl2, verified from 2 separate locations).

Maybe check your MultiPSK settings ? I've never used it but I've been told "In the case of MultiPSK, the freq. shown in VDL2 decodes is the freq. that the user has typed into the frequency box in the MultiPSK screen and is not necessarily anything like the actual frequency if the user has forgotten to change it when he changes freq".

AS

 

[DaveNF2G]

The frequency in the RTL control window tunes the receiver when Forward is clicked. When a new frequency is typed in and Forwarded, MultiPSK writes a new <RX> line to the .qso file reflecting the new frequency.

This frequency, after the offset is applied, is also sent to the logging line in the main RX/TX window.

However, I plan to run the test again because I was very surprised to see so much traffic going to so many different terminals on that frequency. I suspect that something fishy was going on with the logging at my end.

 

[EricCottrell]

Hello,

I am still playing around with VDL2 ground station KML files. I have all the licensed FCC and Canadian locations with known hex addresses. The hex address is accurate to the airport only and not to the site at the airport. I used small square symbols for ARINC and small circles for SITA.

From what I see in observed addressing, the ARINC stations on 136.650 have addresses in the form of 11xxxA. I suspect 11346A is KLAX.

1031EA [KOAK Oakland International 37°42'N 122°12'W] [Oakland]
10346A [KLAX Los Angeles International 33°54'N 118°24'W] [Los Angeles]
1131EA [KOAK Oakland International 37°42'N 122°12'W] [Oakland]
11346A [CALIFORNIA?] [CALIFORNIA?]

73 Eric

 

[AirScan]

Eric,

Thanks for putting that together. I modified the KML file slightly so that confirmed stations (seen GSIF's) show up "green" (with the actual GSIF pasted into the description so it's displayed when you click on the site), while probable stations (not confirmed with an actual seen GSIF) are "orange".

From what I see in observed addressing, the ARINC stations on 136.650 have addresses in the form of 11xxxA.

That seems to be the case. There is also 11512A that is most likely in DTW (If the FCC database is correct, as it would be the only 136.650 station in that area).

[2018-10-23 14:21:04 GMT] [136.650] [-9.0/-46.8 dBFS] [37.8 dB] [0.8 ppm]
ADCCEB (Aircraft, Airborne) -> 11512A (Ground station): Command
AVLC: type: U (XID) P/F: 1
XID: Handoff Initiation
Public params:
Parameter set ID: 8885:1993
Procedure classes: 00 01
HDLC options: 20 a4 88
VDL params:
Parameter set ID: V
Connection management: 01
XID sequencing: 03
AVLC specific options: 27
Destination airport: KDTW

After taking a closer look through some more New York area logs I'm fairly confident with these too:

1023CA = MMU
102C1A = TEB
10347A = PHL
10348A = ISP
10456A = HPN
10502A = PHL

282197 = PHL
2A1457 = TEB

AS

 

[AirScan]

1023CA = MMU is a typo, should be corrected to 102C3A = MMU

AS

 

[DaveNF2G]

Eric,

Thanks for putting that together. I modified the KML file slightly so that confirmed stations (seen GSIF's) show up "green" (with the actual GSIF pasted into the description so it's displayed when you click on the site), while probable stations (not confirmed with an actual seen GSIF) are "orange".

What? No upload?

LOL.

 

[DaveNF2G]

I re-ran the MultiPSK test, ensuring that I was on 136.650 MHz for the entire run.

No traffic received. My previous posting was apparently based on an error in MultiPSK's logging. The IDs are correct, but not the frequency, which must have been 136.975 MHz.

 

[EricCottrell]

Hello,

I went to Bourne for a fleamarket, so I returned home via Providence.

10412A (Ground station, On ground) -> FFFFFF (Aircraft): Command
AVLC: type: U (XID) P/F: 0
XID: Ground Station Information Frame
Public params:
 Parameter set ID: 8885:1993
 Procedure classes: 00 01
 HDLC options: 20 84 80
 N1-downlink: 07 d8
 N1-uplink: 07 d8
VDL params:
 Parameter set ID: V
 AVLC specific options: 20
 Airport coverage: KPVD
 ATN router NETs: 00 00 00 00 00 00	"......"
 System mask: fc 02 00 00
 Ground station location: 41.7N 71.4W

285897 (Ground station, On ground) -> FFFFFF (Aircraft): Command
AVLC: type: U (XID) P/F: 0
XID: Ground Station Information Frame
Public params:
 Parameter set ID: 8885:1993
 Procedure classes: 00 01
 HDLC options: 20 a4 88
VDL params:
 Parameter set ID: V
 AVLC specific options: 20
 Timer T4: 00 02
 Airport coverage: KPVD
 ATN router NETs: 00 00 00 00 00 00	"......"
 System mask: 94 00 00 00
 Ground station location: 41.7N 71.4W

73 Eric

 

[AirScan]

Eric,

I went to Bourne for a fleamarket, so I returned home via Providence.

Thanks once again for the GSIF's. Did you notice how close to the sites you had to get before you started receiving them ?

AS

 

[DaveNF2G]

Here is a summary of information from various posts about general station identities, and the still unidentified stations from my previous logging:

1nnnnA = ARINC on 136.975
11nnnA = ARINC on 136.650
2nnnn7 = SITA
2nnnn8 = SITA
2nnnn9 = SITA

1014FA ?
AAL2702 KMIA-CYUL

10153A ?
CCA989 ZBAA-KJFK
UAL931 KORD-EGLL

10158A ?
UAE212 KIAH-OMDB

10158E ?
VIR8E KLAX-EGLL

10184A ?
CCA989 ZBAA-KJFK

10257A ?
SWA1264 KLGA-KMDW

10258A ?
AAL1044 KLAX-KBDL
CCA989 ZBAA-KJFK
ENV3365 KORD-KPVD
SKW3640 KDTW-KPWM

10259A ?
DAL868 KMSP-KBOS
SKW3725 KDTW-KHPN

102C0A ?
N417LX to CZYZ

104C3A ?
RCH5564 KADW-EFRO

10508A
EDV5390 KJFK-KSYR

208F37 ?
SWG307 SNU-CYUL

211197 ?
CHH7915 ZUUU-KJFK
DAL514 KBDL-KDTW
DAL1562 KDTW-KBDL
JBU334 KSFO-KBOS
JBU688 KLAX-KBOS
PAL127 KJFK-CYVR-RPLL
SWG689 MUVR-CYUL
TSA860 CYUL-MKJS

2154D8 ?
JBU516 KSFO-KJFK

2441D7 ?
QTR708 KIAD-OTHH

 

[EricCottrell]

Eric,



Thanks once again for the GSIF's. Did you notice how close to the sites you had to get before you started receiving them ?

AS

Hello,

It depends on the power and terrain, but I am finding that I can pick up the ground stations within about 8 miles of the airport. You need to be closer for aircraft on the ground.

I am using a ham 6m/2m/70cm antenna to a SDRPlay RSP2. I run dumpvdl2 writing to a logfile. One trick under Linux is I can open two terminal windows and run "tail -f logfile" to monitor the logfile. I run "tail -f logfile | grep -B 2 -A 16 tation," in the second terminal to display ground stations by searching for ground station, on ground output.

I use the -f option of tail all the time as it will output any additions to a file.

73 Eric