Jim Thanks for the insights. Oh I am not selling it for emp. I am simply saying no would be general wants a rusty old steel tower as a career booster. I remember when LORAN C was shut down the president said he was saving $36M a year. Thats drop in the old bucket. I also remember the LORAN C antennas on mobile tower sites for timing along with GPS. Thanks again Jim. Fire up that LORAN C receiver and see what you can hear. Regards Paul
On Wed, Aug 5, 2020 at 5:41 PM jimlux <[email protected]> wrote: > On 8/5/20 12:40 PM, Tom Knox wrote: > > Hi Paul and Magnus; > > Not to mention one space EMP would kill all the Sat systems, where a > ground base system even if affected would be easy to access for repair. > > The vulnerability of GNSS systems to EMP attacks is not all that high - > GPS is, after all, a DoD essential system, and lives in a ridiculously > high radiation environment in MEO - They're also hard to neutrons (based > on published specs for components in the GNSS satellites). > > In most scenarios, LEO satellites get hammered, MEO and GEO not so much. > > https://apps.dtic.mil/dtic/tr/fulltext/u2/a531197.pdf > > "GPS and GEO satellites are threatened only by the very high yield (~ 10 > Mt) detonations of our trial set." > > I'll note that the largest the US has detonated in space are the Teak > and Orange shots 3.8Mt (at <100km), and only Starfish Prime (1.4Mt) at > 400km cased significant problems. > > The usual "use case" for EMP is to affect aircraft and ground based > assets, and the burst height is low (so the air around the burst is > denser - more particle interactions = more current = more field) - > conversely, this reduces the flux at 20,000 km (where GPS is) and > 36,000km (GEO) > > Ultimately, it's that your victim is a Long, long ways away from > whatever the phenomenon is. > > I've been doing a lot of analysis on EMI/RFI effects on precision timing > in GEO+1000km - we are looking at bursts from the sun, and timing it > with GNSS satellites. Things that I agonized over (high power shortwave > broadcasters radiating 500kW into a 24dBi curtain array) in my LEO > satellite at 500km just become a non-issue at 37,000 km. Inverse square > law really helps. > > > Anyway, that DTIC report will give you plenty to geek out over. > > > Yes, there would be significant disruption in timing accuracy due to the > ionized particles - I'm not sure if dual frequency would be enough to > compensate. > > > I think alternate timing and nav systems are good idea, but selling it > as "GPS will be knocked out by EMP" isn't going to get you very far. > > > > Cheers; > > > > Tom Knox > > > > [email protected] > > > > "Peace is not the absence of violence, but the presence of Justice" Both > MLK and Albert Einstein > > > > ________________________________ > > From: time-nuts <[email protected]> on behalf of paul > swed <[email protected]> > > Sent: Wednesday, August 5, 2020 11:21 AM > > To: Discussion of precise time and frequency measurement < > [email protected]> > > Subject: Re: [time-nuts] eLORAN will be on the air GRI 99600 > > > > Hi Magnus been a while since have emailed. > > Its one site that was a test transmitter. Its in New Jersey, USA. > > The goal of the testing I believe is to establish the viability of an > > alternate PNT reference to GPS. Additionally the ability to communicate > > some level of message broadcast. This should be identical to proposals I > > have heard of in Europe. > > But I have no direct relationship to any of this. Like you, a very > > interested observer and hope that eLORAN wins the battle. > > Unfortunately there are many alternate proposals such as using other > > satellites. Hmmm if I wanted to advance my career in the Air Force or > Space > > Force (Yes thats actually real now). > > Would I select the lowly reliable as heck eLORAN at sub $100 M/year to > > operate. Or the glorious space based proposals in $B region. Never mind > > that at least 3 countries now have demonstrated killer satellites. > > Sorry for that editorial. > > Regards > > Paul > > WB8TSL > > > > On Wed, Aug 5, 2020 at 11:04 AM Magnus Danielson <[email protected]> > wrote: > > > >> Hi, > >> > >> Do you know that they would do test with two actual transmitter sites? > >> > >> Cheers, > >> Magnus > >> > >> On 2020-08-05 16:00, paul swed wrote: > >>> Hello to fellow time nuts. > >>> Warm up those old Austrons. eLORAN out of New Jersey has been on the > air > >>> intermittently prior to a test run next week. Due to the storm they > have > >>> lost power and should have it back today or tomorrow. > >>> The intention will be on the air operation till the 20th. That's a long > >>> run. Nice. > >>> Seems the Austron 2100s can be had for reasonable money these days > also. > >>> Enjoy. > >>> Paul > >>> WB8TSL > >>> _______________________________________________ > >>> time-nuts mailing list -- [email protected] > >>> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >>> and follow the instructions there. > >> > >> _______________________________________________ > >> time-nuts mailing list -- [email protected] > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > >> > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
