How exactly does one get submillisecond time of day precision with a sextant? (even if sticks and pebbles are thrown into the mix) I'd say more like ~1 sec precision on a really fine day, it the sextant is wielded by a skilled and practiced operator who has apriori knowledge of his location.
And what about standard frequency dissemination? I'm also upset about the notion of time distribution and transfer by internet. Now there's a fine example of a system that could be brought down by a single competent hacker! And all it takes is one really good solar flare to bring down GPS (and Glonass and the others) semipermanently, if the reports I read are true. I argue that instead of shutting down distribution avenues, NIST should be making additional ones available. A lot has been said lately about how rapidly our technology is exploding. But think about how much of that is critically dependent on precision time transfer over the planet, and how much longer it would take mankind to recover from (insert your favorite disaster here) without good time and frequency transfer still up and working. Dana On Sun, Aug 12, 2018 at 2:06 PM, djl <d...@montana.com> wrote: > all you need for a once a day noon fix is a level surface, a stick, and > some pebbles. > Don > > > On 2018-08-12 08:29, Scott McGrath wrote: > >> And with dependence on GPS we have created a serious vulnerability as >> too many critical pieces of infrastructure are dependent on a SINGLE >> precision timing and positioning system. >> >> I can use a sextant and have a copy of Bowditch. But they only work >> on clear days and nights. >> >> if GPS goes down for any reason. Whats the backup solution? >> >> >> On Aug 10, 2018, at 2:25 PM, Lester Veenstra <m0...@veenstras.com> wrote: >> >> Used to work with Wayne on two time transfer via satellite >> Great guy >> >> >> Lester B Veenstra K1YCM MØYCM W8YCM 6Y6Y >> les...@veenstras.com >> >> Physical and US Postal Addresses >> 5 Shrine Club Drive (Physical) >> HC84 452 Stable Ln (RFD USPS Mail) >> Keyser WV 26726 >> GPS: 39.336826 N 78.982287 W (Google) >> GPS: 39.33682 N 78.9823741 W (GPSDO) >> >> >> Telephones: >> Home: +1-304-289-6057 >> US cell +1-304-790-9192 >> Jamaica cell: +1-876-456-8898 >> >> >> -----Original Message----- >> From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of >> Tom >> Van Baak >> Sent: Friday, August 10, 2018 10:19 AM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] Bicentennial GOES satellite clock >> >> Tim, >> >> Thanks for posting that photo. That space age 1976 GOES clock caught our >> eyes when the paper came out in 2005 (see also pages 11, 12, 13): >> >> https://tf.nist.gov/general/pdf/2013.pdf >> >> There was quite a bit of traffic on time-nuts around 2005 when the GOES >> satellite time service was turned off (and back on, and off, and on, and >> finally off for good). That left many of us with piles of 468 MHz GOES >> receivers, antennae, clocks and led to efforts to re-create the RF signals >> in-home so that GOES clocks would still work. There was even a commercial >> G2G (GPS to GOES) translator. >> >> Anyway, I asked around about that one-off bicentennial clock in the photo >> and neither the authors, NIST, or Smithsonian knows where it ended up. >> There's tons of information on the GOES satellite system and GOES clocks >> in >> the NIST T&F archives: >> >> https://tf.nist.gov/general/publications.htm >> >> Best to search title for GOES, or search author for Hanson. It's a >> fascinating glimpse into the recent past. Yes, it's sad that GOES (and >> Omega, and Loran-C) aren't operational anymore, but GPS does such a better >> job. Plus we now have cable, WiFi, cell phones, the internet, Iridium, >> etc. >> >> If you wanted to build your own Bicentennial GOES Clock, the design was >> published, including source code -- for its i4004 (!!) CPU. If you have >> even >> one minute to spare, see attached image and click on these two PDF's: >> >> "Satellite Controlled Digital Clock System (patent)" >> https://tf.nist.gov/general/pdf/1791.pdf >> >> "A Satellite-Controlled Digital Clock (NBS TN-681)" >> https://tf.nist.gov/general/pdf/452.pdf >> >> /tvb >> >> >> ----- Original Message ----- >> From: "Tim Shoppa" <tsho...@gmail.com> >> To: "Discussion of precise time and frequency measurement" >> <time-nuts@lists.febo.com> >> Sent: Wednesday, August 08, 2018 7:29 PM >> Subject: [time-nuts] Bicentennial GOES satellite clock >> >> >> See the groovy picture at >>> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4847573/figure/ >>> f9-j110-2lom/ >>> >>> If anyone knows the whereabouts or history of the bicentennial GOES time >>> clock display, please let me know! >>> >>> Tim N3QE >>> >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > > -- > Dr. Don Latham > PO Box 404, Frenchtown, MT, 59834 > VOX: 406-626-4304 > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/ > listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.