Based on my irtt data, handover seems to be a low number of milliseconds, perhaps 50ms at most. They do tend to switch sats every 15 seconds, based on the data I collected when the gRPC api was still around. Not sure what the 4 second interval is. On Thu, Jul 14, 2022 at 8:28 AM Sebastian Moeller via Starlink < starlink@lists.bufferbloat.net> wrote: > Hi Mike, > > On 14 July 2022 16:56:21 CEST, Mike Puchol via Starlink < > starlink@lists.bufferbloat.net> wrote: > >The handovers are clear from the RF traces, > > Can you estimate how long a handover takes? And are these linked > somehow to either the 4second or 15second intervals visible in starlink > latency traces? > > > Regards > Sebastian > > > but they won’t indicate per se what satellite is being used. I have a > cunning plan for a rotating vertical metal plate which, given the right > calculations, would block 10° of the FOV, which would allow inference of > the satellite in use. There are also narrowband uplink signals that are > likely used for channel sounding and basic signaling between terminal and > satellite. > > > >The other interesting observation is that the power spike (~200W for 1-2 > seconds) that happens at boot time, corresponds to a burst of these > narrowband transmissions on various frequencies at once. > > > >Best, > > > >Mike > >On Jul 14, 2022, 15:33 +0200, Nitinder Mohan , wrote: > >> Hi Jared, > >> > >> Turns out that SpaceX has deprecated the API calls to get satelliteID > and cellID over gRPC so that information is no longer available. See > https://github.com/danopstech/starlink/issues/27 > >> > >> Too bad since those would have been quite useful to understand > performance trends. > >> > >> Thanks and Regards > >> > >> Nitinder Mohan > >> Technical University Munich (TUM) > >> https://www.nitindermohan.com/ > >> > >> From: Nitinder Mohan > >> Reply: Nitinder Mohan > >> Date: 14. July 2022 at 15:05:42 > >> To: Jared Mauch > >> Cc: Dave Taht via Starlink , Mike > Puchol > >> Subject: Re: [Starlink] starlink at sea > >> > >> > Hi Jared, > >> > > >> > Thanks much for the pointer. This seems promising! > >> > > >> > We have a stationary dish available locally so we can try pulling > information at our end. > >> > > >> > Thanks and Regards > >> > > >> > Nitinder Mohan > >> > Technical University Munich (TUM) > >> > https://www.nitindermohan.com/ > >> > > >> > From: Jared Mauch > >> > Reply: Jared Mauch > >> > Date: 14. July 2022 at 14:57:25 > >> > To: Nitinder Mohan > >> > Cc: Mike Puchol , Dave Taht via Starlink < > starlink@lists.bufferbloat.net> > >> > Subject: Re: [Starlink] starlink at sea > >> > > >> > > I haven’t poked hard, but it does seem you can get it: > >> > > > >> > > currentCellId current_cell_id > >> > > > >> > > Seem to be in the GRPC proto dump from the dish. > >> > > > >> > > > https://github.com/sparky8512/starlink-grpc-tools/blob/main/extract_protoset.py > >> > > > >> > > This should pull it out, if you want from my (stationary) dish I > bet I can run something to pull/dump the info. > >> > > > >> > > - jared > >> > > > >> > > > On Jul 14, 2022, at 8:49 AM, Nitinder Mohan via Starlink < > starlink@lists.bufferbloat.net> wrote: > >> > > > > >> > > > Hi Mike, > >> > > > > >> > > > Do you happen to have a tool that can extract the current uplink > channel of Starlink and (more importantly) which staellite it is connected > to at any given time? I wanted to track the handovers in Starlink and try > to find its impact on network performance but cannot seem to get those > values. > >> > > > > >> > > > Thanks and Regards > >> > > > > >> > > > Nitinder Mohan > >> > > > Technical University Munich (TUM) > >> > > > https://www.nitindermohan.com/ > >> > > > > >> > > > From: Sebastian Moeller via Starlink < > starlink@lists.bufferbloat.net> > >> > > > Reply: Sebastian Moeller > >> > > > Date: 14. July 2022 at 14:35:16 > >> > > > To: Mike Puchol > >> > > > Cc: Dave Taht via Starlink > >> > > > Subject: Re: [Starlink] starlink at sea > >> > > > > >> > > >> Hi Mike. > >> > > >> > >> > > >> Thanks a lot. This is intersting. > >> > > >> > >> > > >> > On Jul 14, 2022, at 14:02, Mike Puchol > wrote: > >> > > >> > > >> > > >> > The uplink is an OFDM signal with 128 subcarriers, looking at > the signal in the time domain reveals a frame length corresponding to 14% > (from memory, 1,1 us frame vs 6.7 us pause). I have two terminals 1 meter > apart and they can each achieve 30 Mbps at the same time over the same > uplink channel. I would expect the satellite to assign a particular set of > slots to a terminal. > >> > > >> > >> > > >> So assuming the 30 Mbps being gross rate and not measured > goodput: > >> > > >> > >> > > >> 30Mbps -> 30 / (1.1/(6.7+1.1)) = 212.73 Mb/s while actively > sending, and > >> > > >> 1000000µs/s / (6.7+1.1)µs = 128205.128205 slots/sec > >> > > >> (30 / (1.1/(6.7+1.1))) * 1000^2 / (1000000 / (6.7+1.1)) = > 1659.27 bits/slot 1659.27/8 = 207.41 Bytes/slot > >> > > >> > >> > > >> with 128 subcarriers that would be approximately an average > >> > > >> > >> > > >> 1659.27/128 = 12.96 or ~ 13 bit/subcarrier > >> > > >> > >> > > >> if all carriers are loaded equally (which is unlikely, I expect > some re-arrangement ot bits between subcarriers to account for different > levels of noise and what not). > >> > > >> > >> > > >> > >> > > >> > If there are any OFDM blind analysis experts in the room, > shout! > >> > > >> > >> > > >> Please do! > >> > > >> Regards > >> > > >> Sebastian > >> > > >> > >> > > >> > > >> > > >> > Best, > >> > > >> > > >> > > >> > Mike > >> > > >> > On Jul 14, 2022, 13:33 +0200, Sebastian Moeller < > moeller0@gmx.de>, wrote: > >> > > >> >> Hi Mike, > >> > > >> >> > >> > > >> >>> On Jul 14, 2022, at 13:15, Mike Puchol via Starlink < > starlink@lists.bufferbloat.net> wrote: > >> > > >> >>> > >> > > >> >>> On the multiple terminals, I have verified that the duty > cycle of a consumer terminal is 14%, thus, you could have 7 terminals on a > single uplink channel with some guard time. > >> > > >> >> > >> > > >> >> Could you elaborate how that works.how the terminals will be > interleaved in that situation? > >> > > >> >> > >> > > >> >> Regards > >> > > >> >> Sebastian > >> > > >> >> > >> > > >> >> > >> > > >> >>> I have seen 30 Mbps up, so you’d be able to push 210 Mbps in > uplink, or a spectral efficiency of about 3.4 bps/Hz. > >> > > >> >> > >> > > >> > >> > > >> _______________________________________________ > >> > > >> Starlink mailing list > >> > > >> Starlink@lists.bufferbloat.net > >> > > >> https://lists.bufferbloat.net/listinfo/starlink > >> > > > _______________________________________________ > >> > > > Starlink mailing list > >> > > > Starlink@lists.bufferbloat.net > >> > > > https://lists.bufferbloat.net/listinfo/starlink > >> > > > > -- > Sent from my Android device with K-9 Mail. Please excuse my brevity. > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink >