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    Re: GPS spoofing for real
    From: Robert VanderPol II
    Date: 2017 Aug 13, 16:48 -0700

    I never used LORAN but I was unhappy to see it go 10yr ago for reasons that are becoming appaent generally.  Chertoff really screwed this one.

    My understanding is that the theoretical calculation of what the TDs should be for any given location weren't very good so there was significant variance between reported location and actual location for LORAN in underway conditions.

    For waypoints that had been established by actually visiting the location and recording the TDs, repeatability was on the order of 10-20m which was better than GPS when initially rolled out with SA enabled.

    Because of the higher power available to landbased LORAN antennae, they are harder to jam.  I don't know about spoofing.

    In dealing with the effects of a Solar Flare or Coronal Mass Ejection (CME), because of the higher power, LORAN will cut out later than GPS and cut back in sooner.  How much sooner or later will depend on the specifics of the event.  One consideration is that a CME has the potential to damage or disable satellites.  An event that damages satellites likely will damage the electrical grid.  Damage to LORAN equipment is also possible due to the long conductors involved in the antennae and the feed lines.  If it is just a current or voltage spike it may be that fuses are all that will be affected and the LORAN will be up an running as soon as the fuses are replaced.

    Re: GPS spoofing for real
    From: Mark Coady
    Date: 2017 Aug 13, 09:36 -0700

    I was curious at the negative thoughts toward recreation of LORAN.  

    I admit I was upset and biased agianst its demise from decades of use for sailing and fishing. "Fishing the 600 line" means lots coordinating between vessels off a paper chart.   I realize that this is a poor basis for national new expenditures of countless dollars.

     I liked it as a primary/backup.    I admit, even in later days with ASF factors, LORAN was less accurate than GPS, but those of us who had dutifully kept logs did pretty well with repeatability.  I always seemed to find the same mark in pea soup fog out of my own coordinate log book.

    If I might ask for commentary on the following, as my knowledge does not give me the technical basis to accept or reject the explanation:

     I was led to believe GPS is a very low power signal.  LORAN being an earth based long wave platform, I was told it is higher broadcast energy and harder to jam or spoof.  If spoofing and jamming are a reality, then any satellite system might have similar vulnerabilty?   Is Loran harder to jam or modify due to wave character, or was this fiction?

    Is a landbased long wave of higher broadcast energy really any better agianst the giant solar flare RF interference doomsday scenario where we lose gps at some point. Or to a megavolcanic eruption (E.G. a Krakatoa or Thera)  that fills the upper atmosphere with junk. I realize these are low probability, but at least potential events.

    On the water I always maintain the ability to navigate by non electronic methods, but I understand many now do not.

    A backup would certainly be nice.

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