Thread: Attn: Radio Operators; AF 447 Transmissions

Seeking help from global amateur radio operators who may have intercepted radio transmissions from Flight 447 :

AF447 - Page 25 - PPRuNe Forums

Post # 497

ACARS txm:s is via VHF ground network or switched to L-band via Satcom. Therefore it is normal that amatuers don´t pick up any of the txm:s on L-band. If the downed 330 had an array-mounted antenna for L-band txm:s and was doing a violent out of control flight, mother in Paris (receiving dish) should have a threshold point on rx, and as the flight may have been doing a lot of txm:s, it would be possible that more txm:s was aired but not recived by "mother" due to the gain-step setting (eB/no) in the receiver in Paris if the array-antenna was out of it´s prime focus during the last minutes.

As there are a minor group of dx:ers active on the L-band (microwave band), it could have been possible that additional data could have been receieved and stored on a hard drive at a l-band fan amatuer, as amatuers always are on the edge of possible receiving limits-settings. The only issue is if ACARS is encrypted and how hard encrypted any ACARS-txm:s would be to decode.

Is there a back-up recordings at Satcom NOC downlink-station, or is Paris the only active downlinker for AF ACARS txm:s. It could maybe be a good idea to spread the world to the L-band people and ask if someone was recording Satcom ACARS on june 1st on 1700 band, especially if worst scenario occurs wheres the "blackbox" never gets retrieved or are in a degraded condition.

Just a thought in this tragic situation.

Sincerely
Thomas in Stockholm / engineer.

Edit-1: Not sure if this link is the right antenna-config, but phase-arrays can be tilted a lot and mantaine communication, suspect more that the CB:s would damp the signal to a critical threshold depending on downlink size of dish and eb/no-setting.
Link is: http://www.emssatcom.com/pdf/AMT-3500.pdf

Edit-2: Also in mind, these array-antennas has a specific radiation pattern, and when accessing satellites, usually the NOC keeps an record on time-signal strength etc for tech-monitoring and billing purposes. So with the NOC data and the previous post of the ACARS messages, it could may be possible to determind the angle of the A/C if a calculation was made of NOC telemetric-data compared with the time-stamp of ACARS txm:s, as we know the pattern and how is mounted on the A/C body.
________________________

End of Post

^ can we have that decoded and written in English please?

^ Translation:
The world is full of amateur detectives/investigators and I am one.

^ Well, get to work.

A Radio Ham would not be able to read any of the messages even if they did manage to pick them up. These messages have individual addresses on them. If they are Ops related that is where they will be addressed. Maintenance messages go to the Technical Dept etc etc. You also need the correct software to be able to decode them.

I don't pretend to understand that jargon, a plea went out to post it on forums so I did. I think one has to have a code source to read it , but radio operators are being asked only to relay the messages , not ascertain the meanings .

any of the txm:s on L-band. If the downed 330 had an array-mounted antenna for L-band txm:s and was doing a violent out of control flight, mother in Paris (receiving dish) should have a threshold point on rx, and as the flight may have been doing a lot of txm:s, it would be possible that more txm:s was aired but not recived by "mother" due to the gain-step setting (eB/no) in the receiver in Paris if the array-antenna was out of it´s prime focus

That's cleared that up then.