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 donīt 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 itīs 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.
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