I thought that Inmarsat terminals had AFC to the sat's down-link. Not to the degree of true phase-lock like DSN has but enough so that the sat's abillity to do doppler correction on the uplink is valid to help with BER, etc... Otherwise the doppler correction would be of no help and not be needed.
-Brian, WA1ZMS/4 iPhone > On Aug 18, 2014, at 12:53 PM, Joe Leikhim <[email protected]> wrote: > > Is anyone paying attention to all the chatter about the lost aircraft MH370, > Inmarsat's supposed flight tracks based on 6 or 7 pings (1 per hour), the > Doppler shift (BFO) and transaction timing (BTO) etc?? > > Basically from my perspective they are putting too much stock into the > Doppler which relies in part upon the stability of the satellite terminal in > the 777 aircraft. My question is how stable an oscillator (reported OCXO - > not confirmed) would be under the extremes of either or both a cabin fire or > decompression event. There is a website (Duncan Steel Blog) where some math > brains are trying to sort out the raw data provided by Inmarsat. They have > made assumptions about the stability of the local oscillator in the > satellite, but I think the aircraft satellite terminal's master oscillator is > a variable they have pushed aside. > > -- > Joe Leikhim > > > Leikhim and Associates > > Communications Consultants > > Oviedo, Florida > > [email protected] > > 407-982-0446 > > WWW.LEIKHIM.COM > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
