This is really a mystery, wonder what is the ELT frequencies used on modern aircraft , is it 121.5 Mhz or the new 406 Mhz. 73 Nitin [VU3TYG]
>________________________________ > From: Michael Chen <[email protected]> >To: amsat-bb <[email protected]> >Sent: Monday, 17 March 2014 8:35 PM >Subject: [amsat-bb] Re: Malaysian airliner puzzle > > >The distance calculated between the satellite and the plane won't be >credible if the time on both are not synchronized, even if the >transmission from the plane is time tagged. As a matter of fact, it's >quite difficult to keep such an synchronization. > > > >Michael Chen, BD5RV/4 >AMSAT-China: http://www.camsat.cn >----------------------------------- >Twitter: http://twitter.com/bd5rv >Email: [email protected] >MSN: [email protected] >Skype: michael-bd5rv > > >On Mon, Mar 17, 2014 at 4:27 AM, James Duffey <[email protected]> wrote: >> I think that the transmissions from the airplane are time tagged, even >> without the data packets being transmitted. By comparing the ping time to >> the time on the satellite, one can tell how far away the ping is. You can >> draw a circle with that radius, taking into account fuel available on the >> airplane and last heading to sort of kind of bound where the airplane is. >> That is where the red circles in the NY Times article come from. >> >> A second satellite is needed to pinpoint a more exact location, but even >> that will have a relatively position error on the ground. I don't think it >> is within range of another INMARSAT. Whether or not other assets exist that >> could receive the signal is a matter of speculation. - KK6MC >> >> >> On Mar 16, 2014, at 2:01 PM, Rick Walter <[email protected]> wrote: >> >>> Tony, since the satellite cannot tell direction of the Ping, only distance, >>> the arcs have the same distance from the plane making up a half circle. You >>> would need to sats to hear the plane, see where the two arcs cross to >>> determine a location. >>> >>> This is the same way seismic stations locate earthquakes. >>> >>> Rick - WB3CSY >>> >>> Sent from Rick's iPhone 5 >>> "Great spirits have always encountered violent opposition from mediocre >>> minds" - Albert Einstein >>> >>> >>> >>>> On Mar 16, 2014, at 12:24 PM, "Anthony Japha" <[email protected]> wrote: >>>> >>>> Those so-called arcs that are said to be possible routes for the plane >>>> look much like the outer edge of one of the Inmarsat footprints. Is there >>>> logic behind the arcs or is it oversimplified nonsense? They are said to >>>> be the result of the signals Inmarsat received. But then why wouldn't it >>>> be possible for the plane to be anywhere in the footprint? >>>> >>>> I'm sure many in our group have good ideas. I'm not trying to start a >>>> discussion of the entire mystery, only this one narrow, but possibly >>>> misleading, aspect related to our hobby. >>>> >>>> 73, >>>> Tony, N2UN >>>> LM 183 >>>> >>>> --- >>>> This email is free from viruses and malware because avast! Antivirus >>>> protection is active. >>>> http://www.avast.com >>>> _______________________________________________ >>>> Sent via [email protected]. Opinions expressed are those of the author. >>>> Not an AMSAT-NA member? Join now to support the amateur satellite program! >>>> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > >>> >>> _______________________________________________ >>> Sent via [email protected]. Opinions expressed are those of the author. >>> Not an AMSAT-NA member? Join now to support the amateur satellite program! >>> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb >> >> >> _______________________________________________ >> Sent via [email protected]. Opinions expressed are those of the author. >> Not an AMSAT-NA member? Join now to support the amateur satellite program! >> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > >_______________________________________________ >Sent via [email protected]. Opinions expressed are those of the author. >Not an AMSAT-NA member? Join now to support the amateur satellite program! >Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > > _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
