[time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy)

J. Forster jfor at quik.com
Sun Nov 15 17:08:17 UTC 2009

> John,
>> If a LORAN transmitter were destroyed by a terrorist team, a backup could
>> be in operation in hours. A damaged GPS system could easily take many
months or even years to fix.
>> -John
> A LORAN site, with a several hundred meter high mast, a small house full
of transmitter, signal generation and Cs clock(s?)... on a remote
Norwegian island... would not be back online within a few hours after an

I think it'd still be a lot easier to replace quickly than GPS jammers
widely seeded.

What would happen if some rogue country started building mini-GPS jammers
and giving them to insurgents to randomly scatter around. A single donkey
could carry many hundreds?

Or suppose a jammer was built into a child's toy and ran intermittantly
off the toy's batteries and sold by the zillions at Walmart for Christmas?

> GPS is supposed to work without _any_ terrestrial support for days or
weeks. I doubt that anyone can get something lethal for the SVs up in
orbit without making it very obvious who they are. GPS now has lots of
hot spare birds in orbit, that a instantly online with one or a few
satellites going bust.

I've never suggested attacking the birds is a credible terrorist threat.
It is not, IMO.

> That said, I think LORAN should be kept running as a backup, also with a
firm commitment that it WILL KEEP running for 10+ years, giving vendors
a reason to develop modern receivers.
> --
>    Björn

IMO, GPS is much more vulnerable to a jamming attack and LORAN must be
maintained as a backup.



More information about the time-nuts mailing list