[time-nuts] eLORAN will be on the air GRI 99600

[jimlux]

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
> 
> actast at hotmail.com
> 
> "Peace is not the absence of violence, but the presence of Justice" Both MLK and Albert Einstein
> 
> ________________________________
> From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of paul swed <paulswedb at gmail.com>
> Sent: Wednesday, August 5, 2020 11:21 AM
> To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
> 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 <magnus at rubidium.se> 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 -- time-nuts at 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 at 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 at 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 at lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>