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KFAT (for kma371) ?

AirScan

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#1
kma371,

I saw your post in the California forum.

I was down at the airport about week and a half ago searching myself for what you found along with searching for active VDL2 data.

I was just wondering if you were able to receive the ground station at KFAT ? Did you get any GSIF data, station ID ?

AS
 

kma371

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#2
kma371,

I saw your post in the California forum.




I was just wondering if you were able to receive the ground station at KFAT ? Did you get any GSIF data, station ID ?

AS
Wasn't able to hear anything down there. There's a license for it, but it must not be active.
 

AirScan

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#3
Ok thanks. I passed by that area recently as well and didn't get anything either. Thought it might be a problem with my antenna ?
 

kma371

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#4
Ok thanks. I passed by that area recently as well and didn't get anything either. Thought it might be a problem with my antenna ?
I think there's a lot we are missing in California. Lots of unknown ground stations.
 

vagrant

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#5
I was just wondering if you were able to receive the ground station at KFAT ? Did you get any GSIF data, station ID ?
What exactly are you looking for? That airport is local to me. I should be able to monitor whatever freq you need and see what I get.
 

kma371

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#6
What exactly are you looking for? That airport is local to me. I should be able to monitor whatever freq you need and see what I get.
VDL2 ground station licensed there. No transmissions received.
 

AirScan

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#7
What exactly are you looking for?

Vagrant, thanks for the offer to check. Are you decoding VDL2 ? Looking for any transmissions from the ground station there on either primary 136.975 or secondary 136.650. You should be able to hear the data chirps using a regular scanner. Athough this is not much use unless you can decode them.

As kma371 mentioned the FCC database indicates there is a ground station at KFAT, that's listed as being active since 2016. The database could be wrong (not the first time) or maybe the site is down for temporary maintenance ? Or we just weren't close enough to get it ?

kma371, have you tried any other locations ? Modesto ? Bakersfield ?

AS
 

kma371

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kma371, have you tried any other locations ? Modesto ? Bakersfield ?

AS
Sat at Modesto and didn't hear anything there either. Bakerfield is just too far for me to play scanners ;)

I thought of taking a trip up to Sacramento but I think we have everything up there.
 

vagrant

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#9
I am not decoding VDL2, but happy to dial up those frequencies and see what's shows up on the waterfall or if I hear something. I am unfamiliar with VDL2, so I will do some reading and see if I can whip up something to confirm tomorrow, one way or the other.
 

AirScan

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#12
I thought of taking a trip up to Sacramento but I think we have everything up there.

I was recently in the LA area and can confirm with ground reception (GSIF) these 3 ARINC stations.

10500A = LAX
10211A = LGB
10303A = BUR

Plus (thanks to tbg's site, see the SoCal thread)

10341A = ONT

Anyone have the ARINC station code for San Jose (SJC) ?
 

AirScan

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#13
FYI for your database

10211A (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: KLGB
ATN router NETs: 00 00 00 00 00 00 "......"
System mask: fc 02 00 00
Ground station location: 33.8N 118.2W

10303A (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: KBUR
ATN router NETs: 00 00 00 00 00 00 "......"
System mask: fc 02 00 00
Ground station location: 34.2N 118.4W

10500A (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: KLAX
ATN router NETs: 00 00 00 00 00 00 "......"
System mask: fc 02 00 00
Ground station location: 33.9N 118.4W
 

vagrant

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#15
Unfortunately, I did not bring a Pi with me to install that program. Perhaps another day as this looks interesting.

Fortunately, there is definitely something on 136.975 MHz and it looks and sounds like VDL2, based on the Signal ID Wiki and what I see on the waterfall. I can also confirm a very similar looking signal(s) on 136.650 MHz. I am across the street from the Fresno airport and some of the signals are very strong. I am unsure which signals are ground or aircraft until I can decode them.

I tried Multipsk, but that program displayed some window advising it was done decoding before I could even get it configured. The user interface on that program is silly. I uninstalled it.
 

AirScan

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#17
I am across the street from the Fresno airport and some of the signals are very strong. I am unsure which signals are ground or aircraft until I can decode them.
The "XID: Ground Station Information Frame" messages (same as the examples I posted from the LA area) are sent every 110 seconds (+/- 10 seconds). So if you are seeing what looks like the same type of message (same length/strength) every 110 seconds or so it might be a GSIF ? If you feel like it and see that pattern and can record it, e-mail it to me and I might be able to decode it off a sound file ?

atcsectors@gmail.com

AS
 

vagrant

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#18
File sent. If it does not work, or even if it does I may get a Pi configured and see what's what. Something new to check out.
 

vagrant

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#19
I believe the following is what you are looking for. At least this is what I captured with other stuff from aircraft and ground in a dump to a text file after letting it run about 60 seconds. I can let it run longer if needed. ( I will now try it at home using a proper antenna to see how far I can receive ground stations ) Anyways, I hope this helps; advise otherwise.

* Attached is a file of another capture for about 10 minutes.

I used the following for whomever stumbles on this thread:
- Raspberry Pi 3 B+
- dumpvdl2 (As advised above)
- $10 DVB SDR USB Dongle
- Radio Shack 20-176 discone sitting in a corner

[2019-03-08 13:10:20 PST] [136.975] [-8.8/-41.2 dBFS] [32.4 dB] [$
10207A (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: KFAT
ATN router NETs: 00 00 00 00 00 00 "......"
System mask: fc 02 00 00
Ground station location: 36.8N 119.7W
 

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AirScan

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#20
vagrant,
I believe the following is what you are looking for.

Yes that's it. I was not able to decode the file you sent me, so thanks for posting that. Very interesting, so there is an active station in KFAT. I suspected there might be reception issues with my equipment when I was in the area and this confirms it. I will get this station added to the database.

Cheers,
 
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