Re: GNSS is not immortal
From: Steve Dunlop
Date: 2018 Sep 27, 10:22 -0700
From: Brad Morris
Date: 2018 Sep 26, 15:19 -0400
<<You wrote: failure to appreciate the nature of an effective Faraday cage....no matter how many handheld units one has aboard as backups -- a GPS only approach to navigation leaves you with something very like a single-point-of-failure for a mission-critical capability required for making a landfall.
In my view, this is an argument for CN. Term it the "Hail Mary" use of CN. After the mariner has a lightning strike, and has discovered that their backup depth of N GPS handhelds are all sequentially bad due to improper stowage, they can finally resort to CN. Hopefully, our careless mariner has the skills, equipment, almanac and tables (under the assumption that the calculator was similarly not protected) available. >>
Lightning is tricky stuff. I would not presume to be able to design and construct a Faraday cage that would allow electronics to withstand a nearby strike. The field strengths involved are large and real-world materials have inconvenient properties like resistance. An extra wrap of plastic film is not a guarantee.
I suppose it would be possible to lose a watch to lightning, though they are probably not as sensitive as radio receivers.