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  • UA2781 lands at Midway Atoll on April 16th 2021

    Posted on by beno Comment

    Settle in, this is going to be a long one.

    Background. Oh so briefly.

    C-Band uses a 6 foot (2 meter) satellite tracking dish on ~3.5 GHz. It picks up the aircraft to ground crew communications.
    L-Band uses a 7 turn 3D printed helix (swapped out from a flaked out patch antenna only 3 days before this went down) on ~1.5 GHz. It picks up the dispatch (ground) to aircraft communications.
    What unfolds is a testament to having a fully configured and well tuned Satcom/AERO ground station. Full credit to my mate in Australia. Andrew runs the station and keeps it tip top. (Even to the point of drilling a hole in the dish to let the water drain out when it tropical pours rain!)
    As well as needing a reliable RF data source, to see something unfold in real time and share it with aviation geeks around the world, you need a real time web-based dashboard with some sort of way to string together the conversation (aka, database).
    My tool of choice is Node-RED. A low code environment with amazing power. A blog for another time.
    Over the years I have been finding ‘interesting’ ways to filter and then be alerted to ACARS messages that are out of the routine. The result is a bit of JavaScript that has a list of carefully curated words, if any are in an ACARS message from any source, I get notified, exactly how depends on the ‘severity’ of the trigger word.

    Ok, enough backstory.

    Messages are going to be tagged as follows:
    ‘Pilot’. This is Pilot to dispatch. They come via the dish.
    ‘Dispatch’. This (in this case) is the United Airlines dispatch operator. They come via the helix.
    ‘Aircraft’. This is the aircraft avionics (software). They come in via the dish.
    Names and other personal details have been redacted. (Captin Walt, if you find this, please drop me a line – I’d love to chat).

    April 16th I was minding my business when this message set the adventure in motion.

    Pilot: A254D8: 01:22:14 17-04-21 AES:A254D8 GES:50 2 .N24974 ! 5Z 2 Flight UA2781 M98AUA2781/DM FODM MSG / PGUM PMDY 16 152212 ROBERTA WOULD U PLZ CALL MY WIFE xxxxx AND LET HER KNOW WE ARE OK…xxxx THE OTHER 2 PILOTS WILL TRY LATER TODAY THANKS.

    This got my attention of course. It is very much of out of mundane.
    Worth a little look right?

    At first glance it looks ok?
    You sometimes see funky numbers in the panel on the left, so the altitude did not set me off.
    Before I could push it from my mind….. Just a few minutes latter, I saw this:

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA P QUDPCULUA-1MSG FROM WHQDM UA2781/16 PGUM PMDY SENT: 13:50:54Z HELLO UA2781, I SEE YOU ARE ON THE GROUND. PLS CALL FODM WHEN ABLE DCAFO

    Ok, so now I am really interested.
    Lets zoom in a bit…

    Right. There is no way they intended to land there!
    Now I am really intrigued and started to put the word out to a few mates. I did not tweet it as I knew it would be complicated, but still let a few avgeeks know on Discord/Messenger/Email etc.

    Pilot: GES:50 2 .N24974 ! 5Z 7 Flight UA2781 M96AUA2781/C4 DISP MSG / PGUM PMDY 16 142733 SEND FORM VIA ACARS NO CELL OR WIFI

    Sounds like the crew is getting sorted, using the aircraft ACARS system to talk to dispatch. Pretty cool.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA M QUWHQVDUA?1MSG FROM DISP UA2781-16 PGUM PMDY YOUR CLEARANCE WAS CANCELLED WITH OAKLAND, AND WE ARE STILL TRYING TO CONTACT ANYONE ON THE ISLAND, ALTHOUGH I SUSPECT THAT SOMEONE WOKE UP WHEN A 787 LANDED. PLEASE LET ME KNOW IF/WHEN YOU GET IN CONTACT WITH ANYONE ON THE GROUND

    Not sure how long ADSBx holds the history, but this what we were looking at:
    https://globe.adsbexchange.com/?icao=a254d8&lat=26.824&lon=177.129&zoom=6.0&showTrace=2021-04-16

    Midway Atoll is an emergency diversion point for ETOPS operations, so it makes sense they went there if there was an issue.
    It looks like they just followed procedure and flew straight in.

    We later read a media report that said they flew around the island a few times before landing, but we have no ACARS or ADSC data to confirm that.
    It also does not make sense to extend an emergency like that.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA W QUNDCULUA~1MSG FROM TOMC CAPT – WE ARE STILL WORKING ON RECOVERY PLAN AND WILL SHARE WITH YOU ONCE WE HAVE THE DETAILS. COULD YOU SEND YOUR FOB AND THE CURRENT AC LOCATION. ALSO, HAVE YOU HAD ANY CONTACT FROM ANYONE ON THE FIELD YET. THANKS

    FOB is Fuel On Board. Its a common way to ask or report how much gas is in the tank. (Sent in weight, either lb or kg or something else, depending on the aircraft owner, crew and region – yay for standards right?).

    Dispatch: GES:50 2 .N24974 ! 5Z 8 Flight UA2781 M97AUA2781/C5 TOMC MSG / PGUM PMDY 16 151158 CAN U EMAIL THE CAPT THE COMPLETED FUMES FORM THNX UNITED.C OM

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA M QUDPCULUA.1MSG FROM TOMC UAL2781-16 PMDY KLAX CAPT – TOMC WORKING ON GETTING SUPPORT FOR YOU. I NEED TO SEND YOU SMOKE/ODOR FORM FOR YOU TO FILL OUT AND EMAIL BACK TO ME. CAN YOU SEND EMAIL OR CALL TOMC SO WE CAN GET THIS TAKEN CARE OF. THANKS

    Ok, so from that we know they landed due to smoke somewhere in the aircraft. Probably the cockpit since the pilot/FO had to smell it. (Remember, it was a cargo flight).

    At this point I am just so stoked that the Inmarsat 143E (Cairns Australia) ground station is working so well at this stage.
    Times like this makes me feel it was all worth it.
    The crazy thing is I sent Andrew a 3D printed 7 turn helix my son printed and I built to replace his SDR-Blog Patch antenna (which was not great), Andrew just got it installed about 3 days prior and its working great.
    We are getting both sides of the conversion live!!!!
    Very excited!
    I missed this one in the timeline while was checking out other stuff….

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! AA H /OAKODYA.AT1.N2497425B581AA4E284D8965041895A4D38B4D0549116CA0870674E9F51041870E2D0A8820A084DDC375CB97499A82BCFA52E4CE8E827CE4126A009901 FANS-1/A CPDLC Message: CPDLC Uplink Message: Header: Msg ID: 11 Timestamp: 13:24:06 Message data: [freetext] PMDY ADVISES THEY CANNOT ACCEPT A B787…IM WORKING ON IT

    CPDLC is “CPDLC is a two-way data-link system by which controllers can transmit non urgent ‘strategic messages to an aircraft as an alternative to voice communications. The message is displayed on a flight deck visual display. The CPDLC application provides air-ground data communication for the ATC service.”
    They are so important and often interesting we filter them out and display them in their own table on the website.
    In this case dispatch are telling the pilot that they knew the aircraft was in distress and Midland was the best option. Dispatch is ahead of the flight (so to speak) and are trying to raise anyone on the island to ready things for the landing.

    Aircraft: While its sitting on the ground sends out automated messages from time to time.

    GES:50 2 .N24974 ! H1 5 Flight UA2781 506IUA2781#T5BG00C00C00000003Q04504U05R02H01H01301931BO1641020630CK0000CN0UF1641590EG60E0C::::::::::::::::::::::1)))0V700N00M00000707)

    Its a bit cryptic, and many of us are working on their exact meaning. Usually its stuff like engine or aircraft health and status data.

    A few of the guys were looking at background information while I was mashing the ‘refresh’ button on the data feed.

    The runway is nice and long. A few guys were looking up the runway length needed for the aircraft and its rough cargo weight.
    No problems there.
    The birds on the other hand…..

    The aircraft is still spewing out automated messages like this one:

    AES:A254D8 GES:50 2 .N24974 ! RA Q QUNDCULUA~1LTD ADVISORY UA2781/16 PGUM PMDY SENT: 17:24:00Z *LENGTHY TARMAC DELAY* THE LTD CLOCK HAS BEEN EXCEEDED. *********************** DIVERSION LTD MUST BE MANAGED BY NOC. LTD BEGINS AT ON AND ENDS AT EGRESS OR OFF. AUTOMATED MESSAGES DO NOT ALWAYS HAVE ACCURATE TIMES *********************** PILOT ACTIONS: PROCEED TO GATE OR EGRESS POINT IMMEDIATELY. NOTIFY DISPATCH/CABIN AND PAX OF STATUS AS REQUIRED. *MANDATORY IOR*

    This is a result of:
    “47 passengers spent almost six hours — longer than it usually takes to fly across the continental U.S. — sitting onboard a plane that was parked on the tarmac of Rochester International Airport in Minnesota.”
    Airlines that defy the tarmac delay rules can be fined up to $27,500 for each passenger on board the affected flight. With commercial jets routinely carrying over 200 passengers these days, that means failure to follow the tarmac delay rules could cost an airline more than $5 million in fines for a single flight. The potential for that kind of financial hit is probably enough to get the attention of even the largest airline.

    So, the aircraft has this tarmac delay built in and messages the pilots that they need to take action and keep track of the time they are on the ground.
    Even though this is a cargo flight, the aircraft share similar software regardless of their ‘cargo’, be it boxes or people.

    Back to the story.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA S QUNDCULUA~1MSG FROM DISP UA2781-16 PGUM PMDY MDY IS IN CONTACT WITH YOU NOW?

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA J QUNDCULUA~1MSG FROM TOMC CAPT – REGARDING THE GPU – I SUSPECT THE AC HAS PLENTY OF FUEL FOR THE APU AND BASED ON NOT KNOW THE CONDITION/RELIABILITY OF THE GPU, LET’S NOT USE IT AND KEEP ON THE APU PLEASE

    APU, aircraft power unit. GPU, ground power unit. The aircraft has to be kept powered up (unless going into long term cold storage – ie, not in this case). Dispatch are saying they don’t know if Midland has the gear to keep the aircraft powered, they know the onboard power unit can do it, so use that one.

    Pilot: GES:50 2 .N24974 ! 5Z 7 Flight UA2781 M14AUA2781/C5 TOMC MSG / —- —- — 174628 ROGER. APU ONLY

    They are going to use the on board aircraft power unit as its a known entity.
    Pretty cool to see the Pilot acknoladge messages from dispatch in real time via satellite from half a planet away.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA N QUNDCULUA~1MSG FROM TOMC THANKS – COUPLE ITEMS – COULD YOU GIVE ME FUEL ON BOARD DETAIL AND WHERE IS THE AC PARKED, ARE WE GOING TO NEED A TOW BAR? THANKS

    After years of reading ACARS messages I personally love the guys in dispatch almost as much as pilots now. They work so hard for the crew (and passengers). This operator is thinking way ahead and wants to be sure they have everything the crew will need to get back in the air before they even need it. A good dispatch operator will reduce the crew work load a lot (I have also seen a fair few snarky dispatch messages FWIW).

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA T QUNDCULUA~1MSG FROM TOMC CAPT – ANOTHER QUESTION CAME UP THIS MORNING AND IT’S A LONG SHOT – BY CHANCE, IS IT POSSIBLE THERE WAS A BAG/CONTAINER OF “MINI NORI MAKI”; RICE CRACKERS IN THE FLIGHT DECK?

    What. What?
    A packet of crackers?
    This cracked a few of us up.
    https://www.snackhawaii.com/products/enjoy-mini-nori-maki-4-oz
    Its a real thing, but still… bit odd for dispatch to ask the crew?

    Pilot: GES:50 2 .N24974 ! 5Z 6 M15AUA0000/C5 TOMC MSG / —- —- — 175821 FOB…70.5 PARKED NEAR LARGEST BUILDING ON AIRPORT NO TOW BAR REQUIRED PLENTY OF ROOM TO TAXI OUT

    Displatch: AES:A254D8 GES:50 2 .N24974 ! RA W QUNDCULUA~1MSG FROM TOMC EXCELLENT! THANKS – ARE YOU ALL STILL STUCK ON BOARD OR DO YOU HAVE ACCESS TO THE RAMP YET?

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA Y QUNDCULUA~1MSG FROM TOMC IF YOU ARE ABLE AND WILLING, IT WOULD BE GOOD TO HAVE A WALK AROUND THE AC TO MAKE SURE NO BIRD STRIKES INBOUND TO MDY AND CONDITION OF THE TIRES. IF WE NEED TIRES, WILL NEED TO TAKE THAT INTO ACCOUNT FOR THE CHARTER OR RESCUE FLT TO CARRY YOUR WAY. THANKS

    Again with dispatch looking ahead and working the situation.
    Also not the first time the ‘bird’ word will come into play on this adventure.

    Pilot: GES:50 2 .N24974 ! 5Z 2 M16AUA0000/C5 TOMC MSG / —- —- — 180846 NO CRACKERS. YES WE HAVE A LOADING BRIDGE. TIRES ARE FINE

    Ooookkkk, so the pilot checked for crackers….

    Displatch: AES:A254D8 GES:50 2 .N24974 ! RA G QUNDCULUA~1MSG FROM TOMC ALL GOOD NEWS – THANKS! APPARENTLY, THERE HAS BEEN HISTORY OF THESE TYPE CRACKERS GENERATING A HOT ELECTRICAL SMELL IN CONFINED SPACES AND HAVE CAUSED DIVERTS IN THE PAST. WHO KNEW! GLAD TO HEAR YOUR ABLE TO STRETCH YOUR LEGS. IF YOU ALL ARE GOING TO BE LEAVING THE AC, WE WILL NEED TO ADDRESS SHUTTING IT DOWN IF THIS HAPPENS BEFORE WE HAVE SOMEONE ELSE TO MONITOR IT. THANKS

    Crackers that smell like smoke!!!
    Bahahahah
    That’s just amazing. Those crackers have caused diverts in the past?! The stuff you learn via ACARS. Just awsome!

    Pilot: GES:50 2 .N24974 ! 5Z 0 M17AUA0000/C5 TOMC MSG / —- —- — 182343 PREFLIGHT SHOWS NO CONCERNS TIRES ARE FINE AND BRAKE TEMPS NEVER EXCEEDED NORMAL RANGE

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA N QUDPCULUA.1MSG FROM TOMC UAL2781-16 PMDY KLAX THANKS xxxxx! DO YOU KNOW WHAT FLT OPS IS PLANNING FOR YOU YET? WWHQ093E

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA S QUDPCULUA.1MSG FROM TOMC UAL2781-16 PMDY KLAX CAPT – ARE YOU ALL STILL ON THE AC WWHQ093E

    At this point I had be following along for more than a few hours and was pretty tired.
    The nice thing is that Node-RED is putting the ACARS messages into a MySQL database on a 24 rolling buffer so I could just catch up in the morning. (A few of my other-side-of-the-planet avgeek buddies kept watch).

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! C1 G .DPCULUA 171434 AGM AN .N24974 – UA2781/17 PMDY PHNL SENT: 14:34:17Z PLEASE CONFIRM BEFORE DEPARTURE: -TOTAL SOULS ONBOARD -CARGO IN THE PITS? YES OR NO -GALLEY OPTION 1,2,3,4 OR 5 1. CREW MEALS IN FC GALLEY, ALL OTHER GALLEY CARTS INSTALLED BUT EMPTY 2. ALL GALLEY CARTS ONBOARD INCLUDING CONTENTS FOR RETURN PASSENGER FLT 3. ALL GALLEY CARTS INSTALLED BUT EMPTY 4. NO GALLEY CARTS INSTALLED 5. CREW MEALS IN FC GALLEY, NO OTHER GALLEY CARTS INSTALLED REPLY UA COMM>LOAD PLANNING OR MISC LP OPBLP

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA I QUDPCULUA-1MSG FROM OPBLP UA2781/17 PMDY PHNL SENT: 14:37:09Z HELLO FROM CHICAGO . IF U PLZ MX WILL BE . LOADING AOG AND TOOLS. THEY BROUGHT W THEM. . PLZ VERIFY IT WILL B . SAME WGHT AND IN THE . BULK PIT. . . QUESTIONS – CONTACT LOAD PLANNER OPBLP

    Right, it seems while we slept a maintenance flight arrived from Hawaii with some crew and gear.
    We did not check out Satcom ACARS for them – in hindsight I will the next time something like this happens.

    Dispatch: (We got a few of these releases, so are only posting the one here)
    AES:A254D8 GES:50 2 .N24974 ! RA Z QUHDQWDUA?1DISPATCH RELEASE UA2781/17 PMDY PHNL SENT: 15:02:08Z DISPATCH RELEASE UAL2781(2781) – 17APR21 PMDY/MDY PHNL/HNL N24974/3974 B789 ———————– RLS 1 FFD AFFIRMATION: PO EMP NAME EMP NO FFD — ———- —— — CA HE GAINES 136588 NO FO AW ADAM 250443 NO ———————— RELEASED IFR TO PHNL CHI55 DEPARTURE ALTN: N/A DESTINATION ALTN: PHJR/JRF 120 ETOPS ENROUTE ALTERNATES: EA:PMDY-PHNL MIN T/O FUEL:36685 THE CAPTAIN AND DISPATCHER NAMES ON THIS RELEASE CONSTITUTES THE REQUIRED SIGNATURES PER 121.663 AND INDICATES THE PILOT%

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA A QUDPCULUA-1EPNF INFO UA2781/17 PMDY PHNL SENT: 15:02:09Z NO DANGEROUS GOODS PLANNED

    Ok looking at that message, we see PMDY (Midlands Atoll) and PHNL (Daniel K. Inouye International Airport, aka Honolulu International Airport). So we know they are going to do a short hop between islands on this flight. Probably to get more fuel in PHNL to finish their original flight to KLAX.

    Aircraft: GES:50 2 .N24974 ! 23 9 Flight UA2781 M26AUA2781/23 CDOORS CLSD / PMDY PHNL 17 150347/TIME 1745 /LOC +28.2097,-177.3793

    Pilot: GES:50 2 .N24974 ! 5Z 6 Flight UA2781 M29AUA2781/LP LOAD MSG / PMDY PHNL 17 151303 9 SOB YES CARGO GALLET OPT 1

    SOB is soles on board.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA Z QUDPCULUA-1MSG FROM OPBLP UA2781/17 PMDY PHNL SENT: 15:17:47Z COPY 9 SOB 2 IN CKPIT. 7 IN FIRST…IS THAT . CORRECT? . . . . . . QUESTIONS – CONTACT LOAD PLANNER OPBLP

    The load planer needs to know how the weight is spread out on the aircraft.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA A QUWHQVDUA?1MSG FROM DISP UA2781-17 PMDY PHNL HI ANY ETD YET? THANKS

    Usually dispatch work with the local ATC, but there is none on Midway Atoll.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA B QUWHQVDUA?1MSG FROM DISP UA2781-17 PMDY PHNL DID THE 737 TAKEOFF YET?????

    United ground support are wondering if the flight that had the maintenance guys on board has cleared the island yet.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA D QUDPCULUA-1MSG FROM OPBLP UA2781/17 PMDY PHNL SENT: 15:20:37Z PLZ VERIFY MX HAS . LOADED AN ADDITIONAL . 750 PDS IN BULK. AOG. AND TOOLS THEY BROUGHT FROM HNL ON THE . NARROW BODY . . . QUESTIONS – CONTACT LOAD PLANNER

    Pilot: GES:50 2 .N24974 ! 5Z 4 Flight UA2781 M30AUA2781/LP LOAD MSG / PMDY PHNL 17 152312 AFFIRM ALL IN 1ST

    Pilot: GES:50 2 .N24974 ! 5Z 5 Flight UA2781 M31AUA2781/C4 DISP MSG / PMDY PHNL 17 152432 ETD 1545 737 HAS LEFT

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA H QUWHQVDUA?1MSG FROM DISP UA2781-17 PMDY PHNL THX CHIDD SWED

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA I QUWHQVDUA?1MSG FROM DISP UA2781-17 PMDY PHNL CAN U PLZ LET LP KNOW THE 750 LBS TOOLS PARTS VERIFIED ON BOARD??? THX

    Pilot: GES:50 2 .N24974 ! 5Z 8 Flight UA2781 M32AUA2781/C4 DISP MSG / PMDY PHNL 17 153309 APPARENTLY WE CANT MAKE OUR WHEEELS UP TIME. MX STILL WORKING ON THE MEL ITEMS. THEY WORKING W/ TOMC

    MEL is Minumin Equipment List. ie the stuff that really really matters to fly.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA K QUWHQVDUA?1MSG FROM DISP UA2781-17 PMDY PHNL RGR THAT AND NO CURFEW EXTENTION RIGHT?

    The crew cant fly without rest. So dispatch always keep track of pilot flight hours and remind the crew when they need to rotate.

    Pilot: GES:50 2 .N24974 ! 5Z 1 Flight UA2781 M33AUA2781/C4 DISP MSG / PMDY PHNL 17 155204 300 POUNDS OF MX GEAR NOT 750 FWIW

    Pilot: GES:50 2 .N24974 ! 5Z 4 Flight UA2781 M34AUA2781/C4 DISP MSG / PMDY PHNL 17 155726 NO EXTENSION YOU WOULDNT WANT ONE B/C THESE BIRDS START SWAR MING LIKE CRAZY BUT WANTED LP TO HAVE MX GEAR WT. LETS GO TONIGH

    Ah, the birds….

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! C1 R .DPCULUA 171558 AGM AN .N24974 – /UA2781/17 PMDY PHNL SENT: 15:58:06Z CAP GAINES PLZ BE /ADVISED WE ARE RE SETTING /YOUR REST FOR A 2030 DEARTURE /PLZ ACK-THANK YOU

    Pilot: GES:50 2 .N24974 ! 5Z 7 Flight UA2781 M35AUA2781/CM CREW DESK / PMDY PHNL 17 160021 PILOT ROGER RESET FOR 2030 THNX

    By this time, some how the media had started to pick up on the adventure and they got some facts wrong or missing.
    https://www.kitv.com/story/43689476/mechanical-issue-prompts-ua-flight-to-make-emergency-landing-at-midway-atoll

    https://www.flyertalk.com/forum/united-airlines-mileageplus/2038144-ua-2781-cargo-only-lax-gum-diverts-midway-atoll-16-april-2021-a.html

    https://liveandletsfly.com/united-787-9-midway-atoll/

    And yet, things were still unfolding, so it was only half the story.

    Aircraft: GES:50 2 .N24974 ! H1 9 Flight UA2781 E14GUA2781#EIB4; 20 504.4;;6554; 21 CLOSED;CLOSED 22 NORM;NOT ACTIVE 23 CLOSED;NOT ACTIVE 24 CLOSED;NOT ACTIVE 25 CLOSED;NOT ACTIVE 26 CLOSED 27 ;18;APR;21;00:35:30

    Typical door closed message, but the timing seemed a bit off. Perhaps the crew closed it and opened it again.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA R CT AND SECURE EA CONNECTOR TO EA HEATER BELOW FD THROUGH ACCESS HATCH. TOMC

    This one left most of us a little in the dark. The heater and fan were the original issue from what we could gather. Perhaps we missed some details that they exchanged with dispatch via cell or wifi (email).

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA B QUDPCULUA-1MSG FROM OPBLP UA2781/17 PMDY PHNL SENT: 06:24:49Z GOOD EVENING. . WHEN READY TO GO, . PLEASE LET ME KNOW . IF 750 LBS OF TOOLS . WERE LOADED INTO THE . BULK COMPARTMENT. . FINAL WEIGHTS TO . FOLLOW. THANKS. . QUESTIONS – CONTACT LOAD PLANNER

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA D QUDPCULUA.1MSG FROM TOMC UAL2781-17 PMDY PHNL WORKING ON YOUR MX RELEASE NOW.

    Pilot: GES:50 2 .N24974 ! 5Z 6 Flight UA2781 M41AUA2781/LP LOAD MSG / PMDY PHNL 17 063026 TOOL ARE IN CABIN

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA G QUDPCULUA-1MSG FROM OPBLP UA2781/17 PMDY PHNL SENT: 06:31:30Z GREAT. ALL 750 LBS . IN CABIN. . . . . . . . QUESTIONS – CONTACT LOAD PLANNER

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA H QUWHQVDUA?1MSG FROM DISP UA2781-17 PMDY PHNL CA PLEASE LET ME KNOW WHEN YOU ARE READY TO GO. I NEED TO UPDATE YOUR RELEASE THANKS CHIDD

    Dispatch: (this is just part of about a 10 part flight plan release – it gives you a feel for the rest of it.
    AES:A254D8 GES:50 2 .N24974 ! C1 B .DPCULUA 180650 AGM AN .N24974 – – MESSAGE FROM CHIDD – ** PART 02 OF 04 ** . CLEARANCE . . *OFP* (FPL-UAL2781-IN -B789/H-SADE3GHIJ1J2J4J5M1P2RWXYZ/LB1D1 -PMDY0733 -M080F370 DCT MDY DCT 27N170W/M084F390 DCT 25N165W DCT ECEDO/M083F390 DCT DANNO/M069F310 BOOKE8 -PHNL0227 PHJR -PBN/A1B1C1D1L1O1S2T1 NAV/RNP2 DAT/1FANS2PDC SUR/260B RSP180 DOF/210418 REG/N24974 EET/PHZH0136 SEL/AFJM CODE/A254D8 OPR/UAL PER/D RALT/PHNL RMK/TCAS) TKOF ALTN DIST TIME FUEL 00.00 0 ARWY POSITION MC DIST TIME MOR FL MACH GS/TAS ZBO COORDINATES %2

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! C1 R .DPCULUA 180651 AGM AN .N24974 – FINAL WEIGHTS UA2781/17 PMDY PHNL SENT: 06:51:48Z ************************ TOG 374055 TOW CHG – 1130 ZFW 324855 CG 27.4 ************************ SOB 009 PSGRS 07/000 -007- (48/204) LAP 00 CREW 02/00 KIDS 00 FD JUMPSEAT-0 FA JUMPSEAT-0 ************************ FLIGHT PLAN RELEASE -2- ************************

    Pilot: GES:50 2 .N24974 ! 5Z 6 Flight UA2781 M47AUA2781/LP LOAD MSG / PMDY PHNL 17 070156 250 ONLY WE LEFT 500 HERE. IT WAS MOSTLY COKE ZERO THAT WE LEFT

    Really nice to hear that they offloaded a good amount of weight in the form of Coke Zero (I’m guessing in a gesture of good will for the Island folk to enjoy for putting them up unannounced).

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA B QUDPCULUA-1INVALID WEIGHTS UA2781/17 PMDY PHNL SENT: 07:04:49Z INVALID WEIGHTS DUE TO A CHANGE IN FINAL LOAD CONFIGURATION. THE PREVIOUSLY SENT WEIGHTS ARE NOW INVALID. NEW WEIGHTS WILL BE SENT AS SOON AS POSSIBLE.

    Dispatch are re-working the weights as a result of the maintenance guys changing the amount of tools and the Coke Zero offload.
    Its really good to see that rules and regulations are not pushed aside even in times like this.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! C1 D .DPCULUA 180706 AGM AN .N24974 – FINAL WEIGHTS UA2781/17 PMDY PHNL SENT: 07:06:24Z ************************ TOG 373555 TOW CHG – 1630 ZFW 324355 CG 27.0 ************************ SOB 009 PSGRS 07/000 -007- (48/204) LAP 00 CREW 02/00 KIDS 00 FD JUMPSEAT-0 FA JUMPSEAT-0 ************************ FLIGHT PLAN RELEASE -2- ************************

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA J QUDPCULUA-1MSG FROM OPBLP UA2781/17 PMDY PHNL SENT: 07:07:02Z COPY. ONLY 250 LBS . TOOLS IN CABIN. . . FINAL WEIGHTS RESENT.. . HAVE A GREAT FLIGHT. . . . QUESTIONS – CONTACT LOAD PLANNER

    Reminder: (FOB) Fuel was 75.5 when they landed, and is now 56.0 Running the APU for all this time took an expected hit.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA S QUDPCULUA-1FINAL WEIGHTS UA2781/17 PMDY PHNL SENT: 07:12:02Z ************************ TOG 379555 TOW CHG – 1630 ZFW 324355 CG 27.4 ************************ SOB 009 PSGRS 07/000 -007- (48/204) LAP 00 CREW 02/00 KIDS 00 FD JUMPSEAT-0 FA JUMPSEAT-0 ************************ FLIGHT PLAN RELEASE ************************
    Dispatach:
    AES:A254D8 GES:50 2 .N24974 ! RA L QUHDQWDUA?1TAKEOFF DATA ** PART 01 OF 01 ** ************************ T/O MDY 06 7800 FT 787-9 GENX-1B74-75 TEMP 21C ALT 30.12 WIND 350/4 MAG 1KT HW 4KT XW TOCG/TRIM 27.4/3.66 ************************ DRY ************************ *FLAPS 15* ** *ANTI-ICE OFF* ASSMD WT. 380.4 ASSMD TMP. 64C ************************ REDUCED EPR -.– N1 *HW* V1 VR V2 88.0 1KT 137 141 145 ************************ TW EPR N1 ATMP V1/VR/V2 0 -.– 88 64C 37/41/45 5 -.– 89 60C 35/40/45 10 -.– 91 55C 33/39/45 ************************ MAX EP

    About this time, the aircaft sent its first position report via ADSC.

    Pilot: WE CANT TAKEOFF TILL 0800Z… CAN YOU EXTEND VOID… PLEASE THANX

    Becasue of birds. They need to take off late so they are all asleep.

    Dispatch: [freetext] APPROVED AS REQUESTED. REVISED DEPARTURE TIME OF 0800Z VOID TIME 0815 [freetext] REST OF CLEARANCE REMAINS THE SAME

    When they depart from these islands with no ATC they have to get clearance from Oakland center which issues the clearance with void times meaning they have to be off in this case by 0815, if not they must get another clearance.

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! C1 M .DPCULUA 180734 AGM AN .N24974 – UA2781 MDY ==================MAINTENANCE RELEASE DOCUMENT================ NOSE/TAIL INBD FLT-DATE-LEG RLS DATE RLS STA-
    SEQ-TIME 0974/N24974 2781-16APR21-1 18APR21 MDY 01-0636Z —————————CURRENCIES————————- AUTOLAND:AUTOLAND LIMIT LAND 2 6067771 —————–INBOUND PILOT DEFECT REPORTS—————– 6166173 P 17APR21 MDY DEFECT: DEFERRING BOTH CAPT & F/O SHOULDER HEATERS PER MEL 2145U AS PRECAUTIONARY AS THEY RUN IN FLIGHT WHEN RECIRC FANS RUN REF LP 615836. ACTION: 17APR DE

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! C1 A .DPCULUA 180734 AGM AN .N24974 – UA2781 MDY ==============MAINTENANCE RELEASE DOCUMENT – CONT============= NOSE/TAIL INBD FLT-DATE-LEG RLS DATE RLS STA-SEQ-TIME 0974/N24974 2781-16APR21-1 18APR21 MDY 01-0636Z A. THE FOLLOWING MUST OPERATE NORMALLY: 1. BOTH AIR CONDITIONING PACKS. 2. AT LEAST ONE LEFT CABIN AIR COMPRESSOR. 3. AT LEAST ONE RIGHT CABIN AIR COMPRESSOR. 4. REMAINING LOWER RECIRCULATION FAN. NOTE: OPERATE LOWER RECIRC FANS SWITCH NORMALLY TO ALLOW REMAINING FAN TO OPERATE. ******** END MEL 2125L OPS PLACA

    We got another C-band (satellite dish) ADSC position update from the aircraft.
    They are on the end of the runway.

    Aircraft: GES:50 2 .N24974 ! BA 1 Flight UA2781 L84AUA2781/OAKODYA.AT1.N24974A1A05E4C3D803B9C181B08C681B0ECE6C006A800A327320034A0054FA644C1EE707A6C4E4A0100040EE5A0C48F FANS-1/A CPDLC Message: CPDLC Downlink Message: Header: Msg ID: 3 Timestamp: 08:05:57 Message data: POSITION REPORT [positionreport] Latitude: 28 09.6′ north Longitude: 176 56.1′ west Time at current position: 08:06 Flight level: 148 Next fix: Latitude: 27 00.0′ north Longitude: 170 00.0′ west ETA at next fix: 08:50 Next+1 fix: Latitude: 25 00.0′ north Longitude: 165 00.0′ west%

    Pretty typical ACARS position report from the aircraft.

    And sure enough, they are on their way to Hawaii.

    Dispatch:
    AES:A254D8 GES:50 2 .N24974 ! RA I QUDPCULUA-1GATE ASSIGN UA2781/17 PMDY PHNL SENT: 08:29:17Z *** OUTBOUND FLIGHT IS A QUICK TURN *** GATE G1 OPEN RAMP FREQ OPS FREQ EON 1026Z GROUND PWR AVAIL -YES- PLANNED GROUND TIME IS 01:00 NEXT FLT UA2781/18 PHNL KLAX ETD 1130Z

    Aircraft:
    GES:50 2 .N24974 ! B6 8 Flight UA2781 L90AUA2781/OAKODYA.ADS.N249741413323438EEC9856E8B9F0D11C71C5555498587C8112FD45F32098580453D Waypoint_Change_Event: Lat = 26.9944 Long = -169.992 Alt = 38996 feet. Time past the hour = 49m 39s FOM = 1F Next waypoint Lat = 24.9999 Long = -165 Alt = 39000 feet. ETA = 00:33:12

    Pilot: GES:50 2 .N24974 ! 5Z 3 Flight UA2781 M79AUA2781/CM CREW DESK / PMDY PHNL 17 085634 PILOT HELLO ALL 3 PILOTS WANT TO DV8 AND FLY ON 2781 HNL-LAX WHICH IS THIS PLANE AND IT LEAVES 1 HR AFTER WE BLOCK IN…

    Pilot: GES:50 2 .N24974 ! 5Z 5 Flight UA2781 M81AUA2781/CM CREW DESK / PMDY PHNL 17 085803 PILOT COULD YOU PLZ GET US LISTED ON IT… SINCE ITS A CARGO…

    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA U 01:00 NEXT FLT UA2781/18 PHNL KLAX ETD 1130Z
    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA Y QUDPCULUA-1MSG FROM OPBCM UA2781/17 PMDY PHNL SENT: 09:43:55Z /HEY CREW, THIS IS THE LATEST INFO WE’VE RECEIVED IN REGARDS TO DEVIATING ON THE CONTINUATION OF YOUR FLIGHT. THEY WILL CLEAR CUSTOMS IN HNL AND WILL NOT BE ALLOWED BACK INTO SECURE AREA BC TSA WILL BE CLOSED. UNLESS THEY CAN CONVINCE CPB TO ALLOW THEM TO STAY ON THE AIRCRAFT THEY WILL NEED TO LAYOVER. THERE IS ALSO NO ONE IN HNL AT THIS HOUR TO PREP ADDITIONAL MEALS. OPBCM DM
    Dispatch: AES:A254D8 GES:50 2 .N24974 ! RA B QUDPCULUA-1MSG FROM OPBCM UA2781/17 PMDY PHNL SENT: 09:45:59Z /FOR THE MOMENT I WILL NOT REFLECT YOU TWO DEVIATING IN YOUR PAIRINGS. IF YOU ARE ABLE TO STAY ON THE PLANE WHEN YOU GET TO HNL THEN CALL US TO UPDATE PAIRINGS/CXL HOTEL. UNTIL THEN I WILL KEEP YOUR HOTEL AND TRANSPORTATION ACTIVE. OPBCM DM

    Pilot: GES:50 2 .N24974 ! 5Z 1 Flight UA2781 M94BUA2781 SO MUCH KEEP US POSTED

    ADSC position report from the aircraft, up to the satellite, down to Andrews greound station, uploaded to ADSB Exchange.

    And with that they are safely back on track.

    I want to thank once again, the guys at ADSB Exhange for ingesting our data and putting up with me on their Discourd server, Andrew for running the 143E station and putting up with my crummy coding ‘skils’ and John in Arizona for prodding me to start this whole thing.


    📂This entry was posted in Life in the USA 📎and tagged

  • Tracking Inmarsat 4-F3 with Node-RED

    Posted on by beno Comment

    This page is out of date.
    Please go to my GitHub site: https://thebaldgeek.github.io/

    For a year now I have been ‘tracking’ Inmarsat 4-F3 for my C-Band ADSC aircraft receiving ground station.
    It has been very crude tracking, but tracking none the less.
    I used a linear actuator with a position feedback resistor. Its worth noting that the position feedback is really critical. Without it you just don’t know where the dish is pointed.

    The actuator is very compact and was around 100 dollars, so not too bad in the over all cost of the project. Its worth noting that you can buy a version without the feedback resistor for about 20 bucks less, don’t skimp. You must have the feedback for this application.
    It is supposed to be lightly weather proof but even so I have it wrapped in a plastic bag to protect it mostly from the nightly runs of the irrigation system.
    Another thing of note is that the actuator is rated for 12 to 24 volts.
    At that voltage, it is way too fast for what we need…. so I have a 6 volt DC power supply driving the unit.

    Now the tracking.
    As you may recall from my main post on the subject, I knew from reading bit and pieces that the satellite makes a slow figure 8 in the sky over a 24 hour period.
    Here is what that oscillation looks like on a graph.

    You can sort of visualize the up and down and slide to side motion of the satellite over 24 hours.
    When we look at a heat map of what its doing in the sky, it all becomes clear.

    The satellite is up there in space, just over the equator, wobbling about.
    To do the initial tracking of it, I got some code help from my son….
    What we decided to do was to break the 24 hours up into 3 hour time slices and move the dish to a preset resistor location every time slice.
    I have removed the GUI so don’t have a screen shot, but it was a very simple grid of boxes that had the user entered resistor location for each time slot.
    Over a period of 2-3 weeks of me watching the signal strength in SDR# I got a feel for where each time slot needed to be and so tuned the dish tracking.
    It worked pretty good with one major flaw…. The satellite has an oh so slightly longer oscillation period than 24 hours.
    This meant that over the space of a month, I would need to re-tune all my 3 hour time slots (again and again).
    This was just way too high of a maintenance task for me.

    Node-RED to the rescue.
    There a group of three satellite tracking nodes; https://flows.nodered.org/node/node-red-contrib-satellites
    You can do a lot of cool things with them, but in the end we only need the one node. Since Inmarsat is not in its drop down pre-select list, we need the TLE node.
    Using the example flow on github you can pull down the TLE for any given satellite.
    Now we have the latest orbit parameters for the satellite we can now track it very accurately.
    (This is in fact how I got the above screen shots of the orbit oscillation and heat map).

    Every hour we run the orbit check and output the satellite position in x,y and z. (Note, I don’t use y or z).
    As you can see from the graph and the heat map, the longitude and altitude drift are not really enough for me to worry about (Or are they? Since I have only just got this going, I am still collecting data on if I should add another actuator and track azimuth well as elevation).
    The output latitude data simply goes into a range node which remaps the -3 to +3 deg swing to the resistor value in the actuator.
    The output of that node goes into the micro-controller which has some very simple code of making sure the resistor matches the commanded resistor value by switching the up and down motor relays.
    So, in short, every hour we send a resistor value that equates to the satellite position to a motor controller that measures the actual resistor value and adjusts it to match whats coming in.
    Here is what it looks like in action.

    Pretty easy to see where I turned on the new system. 8am Friday morning.
    Here is a week long graph that better shows how my tracking was working over the Node-RED tracking.

    It has transformed the tracking accuracy and will take the burden off me having to watch it and re-tune it.
    I can now just let it run knowing it is going to be super accurate all the time.
    To say I am very happy with how well it came together is an understatement.
    Why then did I not do it this way a year ago? I simply did not know about the TLE Node.


    📂This entry was posted in Computers 📎and tagged

  • Data from plane tracking.

    Posted on by beno Comment

    People are finding different uses for aircraft tracking data.

    https://www.bloomberg.com/news/articles/2019-07-02/hedge-funds-are-tracking-private-jets-to-find-the-next-megadeal

    Where there’s a jet, there’s a data trail, and several “alternative data” firms are keeping tabs on private aircraft for hedge funds and other investors.

    More power to them, and I am glad that my freely supplied data can make them money.
    (Wow, that sort of sounded like a load of scorn… hehe).

    Also; https://dictatoralert.org/
    and; https://www.jettrack.io/


    📂This entry was posted in Computers 📎and tagged

  • Thermal drift issues

    Posted on by beno Comment

    This page is out of date.
    Please go to my GitHub site: https://thebaldgeek.github.io/

    The feedhorn / down converter on the dish has a pretty bad thermal drift issue. The output frequency is just not stable. It wanders around all over the place.
    We have tried to settle it down by insulating it like thus;

    It helps, but eh, its not the best way to do it as it does run hot, but it chops off about 10 Deg C of drift.
    I think long term I might need some active temperature control, but that is only going to help so much. I think I need to see about a different feed horn.
    Very disappointed.


    📂This entry was posted in Computers 📎and tagged

  • C-Band ADSC aka Satellite ADSB

    Posted on by beno 7 Comments

    This page is out of date.
    Please go to my GitHub site: https://thebaldgeek.github.io/

    When you write it down, in one sentence, its really very simple;
    6′ dish -> PLL LNA -> 18v DC pass-through PSU -> RTL-SDR -> SDR# -> Jaero -> VRS.
    And with that signal path, you will have planes on a map. 100+ planes from half the planet. Easy right. Ah. It could be, but if you are reading this, you probably have hit some snags.
    Also, if you are reading this, you probably have an idea of what you are trying to do, so I will skip the intro and go straight to how I did it.
    And just to be clear, we are talking about ADS-C, not ADSB, but it looks so similar that many (me included) often get it mixed up.

    You can (apparently) get by with a 4 foot dish, but I did not want to be scrapping around in the noise, so opted for a 6 foot dish, the wife was not so excited, so we both compromised and went for a 5 foot dish. If I was going to do it again, I would go a 6 to 9 foot dish, anything bigger and the pointing accuracy is going to be a ‘problem’ and not worth the extra signal strength.

    The LNB (feed-horn) matters. You want something with low frequency drift, something that is temperature stabilized would help as well. If you find something that fits the bill, let me know.
    I was recommended this one; https://www.amazon.com/gp/product/B00HVM08JI
    Having nothing to compare it with makes it a bit hard, but the short of it is that its not really stable enough. The drift will put the signal out of range of the bandwidth every hour or so. You will be chasing the signal over a few hours. Okay for testing, but no fun for something that you just want to leave running unattended (which is my plan).
    The LNB has two voltages, 13 for one polarization, 18 for the other (horizontal and vertical for example). I did not have 13 on hand, so went with 21. A little on the high side, but it runs fine through 50 feet of coax. This is the one I used; https://www.amazon.com/gp/product/B005AME7Y8
    You need to make sure that your power injector can pass through a 1.5gHz signal, that is the down converted signal from the LNB.

    From the LNB power supply, you then have your RTL-SDR. Anything that will work at 1.5gigs should be fine for a test, but you really need something that is stable and sensitive. If you find something that works, stick with it.
    This is the one I am using; https://www.amazon.com/gp/product/B0129EBDS2
    Again, I have nothing to compare it with. (I just wonder if this is not the source of the drift I am fighting with).

    I chose to use SDR#, its free, simple to install and basic enough to do the job. Sure, you can get fancy and run some other software, but its mostly a headless setup, so simple is better.

    Once you have the signal, you need to decode it. I only know of one application that can do it, Jaero. Jonti’s work is amazing, be sure and give him a few bucks if you go this way.
    What you do with the information I will leave it to you. There seems to be two main paths, Plane Plotter or VRS (Virtual Radar Server). I went with the second option since that’s what I already run (I also run PP, but not to the same extent as VRS).

    Ok, so that’s the easy part, now getting it to all play nice together and get planes on a map……

    We bought the dish new off eBay. it arrived, free shipping, in two weeks from Canada.
    Took me about 2 hours to put it together, seems pretty straight forward. If I had to do it again, I would get at least 6 foot and something that mounts on a pole, not a base.

    The LNB was brand new from Amazon. Long story short, it was faulty. I spent a week working with it for hours and saw nothing but static.
    One evening I just gave up and voided the warranty and opened it up. Sure enough, it had a dry joint and was open circuit on the input. A quick touch with a hot soldering iron and put it back together (interesting note aside, the heat sink is there for looks only, it has zero contact with any parts – made me smile a little).

    After spending a week looking at nothing but noise, once I powered it back up I was met with wall to wall signals, it was very exciting and a big ups that I was not losing my mind.

    SDR#. Install it and run it.

    Now the really hard part. What frequency should you tune for? In the end, I could not really find a solid answer since it depends on the down converted frequency of the LNB and the specific satellite you are tuned to. I am looking at Inmarsat 4-F3.

    There are a few lists floating around, but they did not agree and in the end it was a single screen shot on Jonti’s website that got me close.
    it helps to look and see what sort of waterfall pattern the adsb messages makes as well. I mostly went by visual on the waterfall more so than the frequency.
    I wish I had something more solid to give you than ‘look for this pattern’, but that’s really what it came down to. I just could not find anyone that had documented the frequencies for the different sats with the LNB I was using.
    Here are some examples from my setup.

    This next one is a bit more zoomed in on the frequency scale and shows you both the frequency I was tuned to and what the waterfall looks like.

    Now for the next hard part. Aiming the dish.
    A few things to try.
    You can get a compass and inclination meter and point it using those. Not a bad way to do it, and I got in the ball park with this method, but it was not really accurate enough. BTW, the metal in the base will throw things off, so use a plank of wood to extend the dish and put the compass at the end of the wood to get more accurate.
    You can also use one of the satellite aligning apps on your phone. I also did this and found it really good.
    Here is a screen shot looking next to the satellite. (I found the arc of geostationary satellites really fascinating).

    The third way takes a little more gear, but is rather interesting (thanks again go to Jonti for his description of this method), disconnect the LNB and put a modified GPS patch antenna at the center of the feed horn and tune your SDR to the L-Band signals coming from the sat. Now you can pretty easily move your dish around for peak signal from the sat.
    Here is some of the gear I used to test this.
    GPS patch antenna, LNA and bias T injector.

    Here it is on the feed-horn.

    I also did this to see what it was like and it works pretty well.
    So in the end, I used all three options to get the dish pointing in the right rough direction.

    By now, you should have a pretty solid waterfall of signals, find the short staccato signals and start to tweak things for maximum signal.
    One important thing to note, Jonti mentions that I would need the bit of dielectric stuffed in the feed-horn to turn from direct (horz or vert) polarization to circular. He is right. Listen to him. The key is to get it inserted the correct way, there are two ways to put it in, they are 90 deg to each other (up and down or left right if you have the ‘heat sink’ uppermost).
    Make sure you test both ways. One way will make the signal weaker, the other way will make the signal stronger. No dielectric will be somewhere in the middle. You clearly want the strongest of the options.

    Hone in on a likely looking signal and fire up Jaero and see what gets decoded.
    As far as setting it up for the basics, you need to select 10500 bps burst and I found the best decoding to happen when the locking is set to 1800 or 900 hz and AFC is on. (Note, this may or may not make much of a difference. But please experiment with it. I am finding some differences but need more time with it testing).
    Set SDR# to 10500 bandwidth (or wider, but not narrower) and USB.
    You should start to see ACARS data. If in the SU’s tab you see a LOT of ‘Bad R/T Packet’ messages, you are close, but don’t have things setup quite right. Go back over my notes and take a look at my settings and yours.


    IMPORTANT NOTE. In this screen shot I have ‘Locking’ set wrong. It should be 1800 or even 900.

    Once you are getting good clean ACARS data you should straight away notice that you are getting a lot of reports with Lat/Long in them.
    We can push these messages to another bit of software and get the final goal of all this, planes on a map.

    If you are using Plane Plotter, Google will guide you. I cant help.
    If you are using VRS, here is how you set things up…..

    Jaero is a little ‘odd’ in that you set the Basestation address to be 0.0.0.0:30003. You can change the port number, but you MUST leave the IP address to be all zeros.
    This is the odd bit and cost me a ton of time, but in the end, Jonti himself set me straight in a very kind email.


    (Note. In this screen shot I have the ACARS option ticked and its going to the same PC as VRS on a different port number. You wont need to do this for just ADSB.
    I am also interested in looking at the ACARS data in Node-RED. Read about it on my aircraft page.)

    In your VRS then, you need to put the IP address of the PC running Jaero (assuming its on a different PC, if its the same, then its just 127.0.0.1 and the port number) and the port number you picked.
    Of course the type has to be Basestation. Tick the box, ‘Is Sat-com’ to give yourself the longer time out.

    Ok, Phew. By now you can take a breath and check out some amazing data flowing in. You should, within just a few minutes (yes, it really does happen that fast) see planes from all over the world (just about). The foot print of the satellite is amazing.

    Want to double the amount of data/planes you are getting?
    Notice that there is another ADSB signal next to the one you are on….. If you tune over it you will see much the same ACARS/ADSB data but from different aircraft.
    Install the VFO plugin for SDR# and also install VAC (Virtual Audio Cable).
    Now you can set 1 cable for the main frequency and 1 for the VFO.
    Now copy paste a second instance of Jaero on the desktop, right click and set its properties to be -s line2 and now you can start another instance of it and have double the messages.

    Here is the key, you cant run them both on the same port number. The second instance still must be 0.0.0.0 but the port number MUST be different for each instance.
    So set up a second receiver in VRS and make sure you are getting another set of data / aircraft.
    Then set up a merged feed with the two feeds into one to see the total of the two frequencies.

    To-do.
    1. The output of the LNB drifts. I don’t know if its due to temperature, PLL instability or Doppler from the sat moving or drift in the RTLSDR. At the moment I have to tweak the VFO in SDR# a few times a day. This will not do. I need to solve this asap.
    2. The satellite drifts in a slow figure 8 pattern. The dish needs re pointing a few times over 24 hours. At the moment, it looks like just in elevation. I have a linear actuator on order and will see about automating it as a matter of some urgency.

    Hope that helps. I have written what I found scatted all over the place, a lot of what was not written anywhere and the rest is what I wish was written down somewhere.

    UPDATE 1. May 2020. After about a year, I figured out how to accurately track the satellite.
    UPDATE 2. June 2020. I fixed the drift issue and finally blogged about it. https://thebaldgeek.net/index.php/2020/06/07/titanium-c1-pll-lnb-gpsdo-modification-for-c-band-adsc/


    📂This entry was posted in Computers 📎and tagged