Comments on: Another LORAN-C Bites the Dust http://www.kb6nu.com/another-loran-c-bites-the-dust/ Having fun with amateur radio Thu, 17 May 2012 01:28:07 +0000 hourly 1 http://wordpress.org/?v=3.3.2 By: David Brodbeck N8SRE http://www.kb6nu.com/another-loran-c-bites-the-dust/#comment-322474 David Brodbeck N8SRE Mon, 17 May 2010 19:49:56 +0000 http://kb6nu.com/?p=2629#comment-322474 Besides what's noted above, GPS is also vulnerable to temporary local disruptions during severe thunderstorms...I've seen it happen before where there was so much cloud overhead the signal couldn't penetrate. (Then again, I don't think LORAN was ever very reliable during thunderstorms, either, due to the higher noise floor.) I'm less worried about intentional disruption of GPS or re-enabling of selective availability. There'd be a lot of lobbying against such an action, and it's not like the military couldn't shut off LORAN-C at will, too (in fact, they just did!) Also, even in the old "selective availability" days, GPS was *still* not really any less accurate than LORAN, which according to Wikipedia had an absolute accuracy of around a tenth of a mile at its best. My suspicion is they had to cut funding somewhere and LORAN-C lacked a strong advocate to lobby for it. It's a mature system, so there aren't any contractors who stand to make a lot of money off it -- unlike GPS, where they have to keep building new satellites. Besides what’s noted above, GPS is also vulnerable to temporary local disruptions during severe thunderstorms…I’ve seen it happen before where there was so much cloud overhead the signal couldn’t penetrate. (Then again, I don’t think LORAN was ever very reliable during thunderstorms, either, due to the higher noise floor.)

I’m less worried about intentional disruption of GPS or re-enabling of selective availability. There’d be a lot of lobbying against such an action, and it’s not like the military couldn’t shut off LORAN-C at will, too (in fact, they just did!) Also, even in the old “selective availability” days, GPS was *still* not really any less accurate than LORAN, which according to Wikipedia had an absolute accuracy of around a tenth of a mile at its best.

My suspicion is they had to cut funding somewhere and LORAN-C lacked a strong advocate to lobby for it. It’s a mature system, so there aren’t any contractors who stand to make a lot of money off it — unlike GPS, where they have to keep building new satellites.

]]> By: Mike W2MJZ http://www.kb6nu.com/another-loran-c-bites-the-dust/#comment-322461 Mike W2MJZ Mon, 17 May 2010 05:47:52 +0000 http://kb6nu.com/?p=2629#comment-322461 Huhhh?????? Perhaps I don't get the reasoning here, but 160 meters became so very popular due to the demise of Loran A many years ago which was centered right in the 160 meter band. The demise of Loran C, which is centered around 100 kHz, has no effect on 160 meters. However, the destruction of that Port Clarence Loral C tower along with the operational Loran C system was about the stupidest thing our idiotic bureaucrats in Washington have done in a long time. The Loran C system didn't cost very much to operate, and it did provide a very functional backup to the operational GPS system. The problem with the GPS system is that it is vulnerable to intentional disruption by the military, the military of other nations either through spaced based or earth based platforms, space debris, or extreme solar events. From what I can see in the video, the tower seemed to be in very good repair, and perhaps it should have simply been left in "mothballs" with the rest of the system in the event that something unforeseen happened in the future. Mike W2MJZ Huhhh??????

Perhaps I don’t get the reasoning here, but 160 meters became so very popular due to the demise of Loran A many years ago which was centered right in the 160 meter band. The demise of Loran C, which is centered around 100 kHz, has no effect on 160 meters.

However, the destruction of that Port Clarence Loral C tower along with the operational Loran C system was about the stupidest thing our idiotic bureaucrats in Washington have done in a long time. The Loran C system didn’t cost very much to operate, and it did provide a very functional backup to the operational GPS system.

The problem with the GPS system is that it is vulnerable to intentional disruption by the military, the military of other nations either through spaced based or earth based platforms, space debris, or extreme solar events.

From what I can see in the video, the tower seemed to be in very good repair, and perhaps it should have simply been left in “mothballs” with the rest of the system in the event that something unforeseen happened in the future.

Mike W2MJZ

]]> By: rmd http://www.kb6nu.com/another-loran-c-bites-the-dust/#comment-322455 rmd Sun, 16 May 2010 23:43:01 +0000 http://kb6nu.com/?p=2629#comment-322455 Besides the satellite failures (we're well under the ideal number of GPS satellites currently, although they're adjusting orbits to try and get better coverage), satnav is often sub-optimal at extremes of latitude due to auroral effects. Not to mention the sunspot cycle ramping up. See also, http://www.space.com/news/out-of-control-satellite-threatens-others-sn-100503.html LORAN is not a great solution, but for $15M-$30M per year (the latest figures I've heard), you get a not-great-but-often-sufficient solution for less than the cost of a GPS satellite. GLONASS (the Russian GPS system) is supposed to be improving as they throw more money at it, but it's not there yet by any means. It's only been 10 years since the Clinton administration shut off Selective Availability, making GPS usable for the civilian market. If there's ever a political/military/strategic reason to re-enable it, global navigation is going to become a lot more difficult with 100m of inaccuracy. Besides the satellite failures (we’re well under the ideal number of GPS satellites currently, although they’re adjusting orbits to try and get better coverage), satnav is often sub-optimal at extremes of latitude due to auroral effects. Not to mention the sunspot cycle ramping up. See also, http://www.space.com/news/out-of-control-satellite-threatens-others-sn-100503.html

LORAN is not a great solution, but for $15M-$30M per year (the latest figures I’ve heard), you get a not-great-but-often-sufficient solution for less than the cost of a GPS satellite.

GLONASS (the Russian GPS system) is supposed to be improving as they throw more money at it, but it’s not there yet by any means.

It’s only been 10 years since the Clinton administration shut off Selective Availability, making GPS usable for the civilian market. If there’s ever a political/military/strategic reason to re-enable it, global navigation is going to become a lot more difficult with 100m of inaccuracy.

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