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Old 26 August 2007, 11:29   #31
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Not to bore, but I'm interested in this.

Ah ha.

I found this opinionated site that never the less describes what's going on with the Loran C issue. It appears from the comments that Loran C is kept on life support as a backup to commercial air traffic, only. No one wants to build combo GPS/Loran receivers due to the uncertainty of its future.

There are some nasty comments relative to European Politicians imbedded in the article....I just can't imagine

http://phk.freebsd.dk/loran-c/Politics/
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Old 26 August 2007, 11:48   #32
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My main concern with all digital systems is the ease with which they can be jammed. For example you can get a mobile/cell phone jammer the size of a briefcase that will take out a whole street.


It is a similar situation with GPS - even if deliberate jamming is unlikely accidental jamming does occur.

"Man-made interference can also disrupt, or jam, GPS signals. In one well documented case, an entire harbour was unable to receive GPS signals due to unintentional jamming caused by a malfunctioning TV antenna preamplifier. Intentional jamming is also possible. Generally, stronger signals can interfere with GPS receivers when they are within radio range, or line of sight"

And read this about home made jammers.

http://computerworld.com/securitytop...,77702,00.html
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Old 26 August 2007, 12:11   #33
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I think it is important to diferentiate between the two purposes of a compass.
They can be used as a steering compass or "location/bearing compass"
For the latter a hand held is just fine. If you are out of site of land on a cloudy day or at night or in fog then a hand held will tell you which way to go to get to land. I personally find any analog steering device easier to use to steer by than a digital one, However, you need to learn how to average your course. However, if you have not studied a chart of your boating area you are probably "up a creek without a paddle" anyway.
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Old 26 August 2007, 12:22   #34
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[QUOTE=codprawn;216053] My main concern with all digital systems is the ease with which they can be jammed. For example you can get a mobile/cell phone jammer the size of a briefcase that will take out a whole street. Quote]

I don't know if you read the essay on the link I provided but that guy agreed that jamming GPS is dreadfully easy. He further stated that Loran "radio" signals were far more robust but the ease of which the transmitter sites could be targeted makes that system vulnerable.

This has probably gone out of the compass realm at this point. I'm going to do some more digging and post to the Electronics Forum.
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Old 27 August 2007, 15:22   #35
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Retraction!

I hereby retract my statement that GPS is Bullet Proof. For those of you fortunate enough to be in areas of Loran C coverage though, help is on the way. The discussion is in Electronics under Loran C/GPS/? There are some very interesting comments there by an industry player. Integrated eLoran/GPS receivers are on the way for marine applications and will provide something much closer to bullet proof reliability. Cost is not announced but usually within a reasonable period of time costs come down....

Tomas
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Old 27 August 2007, 17:19   #36
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Old 31 December 2007, 18:23   #37
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I cannot believe that people will pay tens of thousands if not hundreds of thousands for a boat then begrudge a hundred or so for a professional compass swing by a compass adjuster.
Compass any day for me.
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