# Loran to GPS Conversion



## Nat (Oct 10, 2007)

I converted a Loran TD to GPS on a Garmin unit

how far apart are these numbers

converted to this 

30 08 248
87 33 833

the published public reef # is
30 08 760
87 33 852

How do I determine how many feet or yards off the conversion is ?


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## Tuna Man (Oct 2, 2007)

Go out there with both a GPS and Loran. If converting FROM Loran, mark spot on GPS. Crossover conversions are close, but not as precise as being on top of the spot.

http://www.andren.com/features.cfm

http://offshorehunter.com/OffshoreHuntersoftware.htm


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## Nat (Oct 10, 2007)

I'm trying to calculate how far off I am

I don't plan on getting a Loran since they are pulling the plug on Loran (again)

so, if I'm close..25 feet to 100feet I'll scout around a little


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## Nat (Oct 10, 2007)

They are pulling the plug on Loran

but leave it to the government to update it and close it down both at the same time

they need the money to give to AIG

http://www.arrl.org/news/stories/2009/03/11/10694/?nc=1<H3>US Coast Guard to Discontinue LORAN Stations</H3></DIV><DIV class=pixLeft><DIV class=image> 
</DIV></DIV>

Last month, the US Coast Guard announced that due to economic conditions, they would be closing down the 24 LORAN-C (Long Range Aid to Navigation) stations operated under the auspices of the USCG. LORAN stations provide navigation, location and timing services for both civil and military air, land and marine users. According to the USCG, LORAN-C is approved as an en route supplemental air navigation system for both Instrument Flight Rule (IFR) and Visual Flight Rule (VFR) operations. The LORAN-C system serves the 48 continental states, their coastal areas and parts of Alaska.

On February 26, 2009, the Office of Management and Budget (OMB) publicly announced the President's Fiscal Year 2010 Budget. In the section for the Department of Homeland Security (DHS), the budget "supports the termination of outdated systems such as the terrestrial-based, long-range radionavigation (LORAN-C) operated by the US Coast Guard, resulting in an offset of $36 million in 2010 and $190 million over five years." The USCG, once a part of the US Department of Transportation, is now under the direction of DHS.

LORAN-A stations were developed beginning in World War II, and signals were transmitted on frequencies in and around our present-day 160 meter band. LORAN-A was responsible for reduced amateur radio operations, including frequency and power limitations, on 160 meters in the United States. In 1979, the Coast Guard phased out the LORAN-A stations; they were replaced by LORAN-C stations. The newer stations operated on 100 kHz, enabling the restrictions on 160 meters due to LORAN functions, to be dropped.

According to the Coast Guard, the nation's oldest continuous sea-going service will continue to operate the current LORAN-C system through the end of fiscal year 2009; it is in the process of preparing detailed plans for implementing the fiscal year 2010 budget. According to USCG Vice Commandant and Chief Operating Officer Vice Admiral V. S. Crea, further details of the LORAN-C termination plan will be available upon the submission of the President's full budget. -- _Some information provided by Cliff Appel, W7CGA_

<BR clear=all>


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## Nat (Oct 10, 2007)

http://www.navcen.uscg.gov/loran/default.htm<H3>LORAN-C Current Status </H3>

LORAN-C provides coverage for maritime navigation in U.S. coastal areas. It provides navigation, location, and timing services for both civil and military air, land and marine users. LORAN-C is approved as an en route supplemental air navigation system for both Instrument Flight Rule (IFR) and Visual Flight Rule (VFR) operations. The LORAN-C system serves the 48 continental states, their coastal areas, and parts of Alaska. The following links show LORAN-C planned and emergency outage information.<UL><LI>Current Atlantic Area LORAN-C User Notifications <LI>Current Pacific Area LORAN-C User Notifications </LI>[/list]

On February 26, 2009, the Office of Management and Budget (OMB) publicly announced the President's Fiscal Year 2010 Budget. In the section for the Department of Homeland Security, the budget "supports the termination of outdated systems such as the terrestrial-based, long-range radionavigation (LOrAN-C) operated by the U.S. Coast Guard resulting in an offset of $36 million in 2010 and $190 million over five years." For more information on the proposed FY2010 Budget, visit the OMB website under President's Budget. 

The Coast Guard will continue to operate the current Loran C system through the end of FY2009 and is preparing detailed plans for implementing the FY2010 Budget.


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## sealark (Sep 27, 2007)

Don't rely on one conversion as being the same for another number even if they are in the same area. You will have to take the converted GPS number and look around sometimes for quite a while then when you find the spot mark it with correct GPS and next time it will be near perfect. My point being that Loran was much less accurate than Gps so one number might look like the conversion was really close and the next number might convert to 1/4 mile difference.


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## lobsterman (Sep 30, 2007)

I have seen the conversion be as far off as 1/2 mile, and that is the kiss of death if you are looking for something small like a private spot. The only way I know to do it right is to run both and save to GPS. Most accurate way period.


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## Nat (Oct 10, 2007)

Someone sent me this link for calculating distance between points

http://www.movable-type.co.uk/scripts/latlong.html


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## lobsterman (Sep 30, 2007)

Thats all good but that doesn't help for loran td's


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## bellafishing (Oct 1, 2007)

I used my Garmin to convert Loran numbers, BUT I had a Loran on my boat. I powered up the Loran and the Garmin. Compared the numbers, and plugged in the offset in the Garmin until they matched EXACTLY. So far it has been pretty damn close. Within 50 yards or so. I just finished converting about 550 numbers a coowrker gave me. It's a pain and you have to punch them into the GPS by hand, but it's worth it if you find some kick-ass spots.

Bob


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## Nat (Oct 10, 2007)

How do you plug in the offset ?


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## bellafishing (Oct 1, 2007)

If you have a spot already in Loran and GPS, put your GPS in Loran mode and punch in the Loran coordinate. Go back to the menu and switch back to GPS and pull up the coordinate. Compare it to the known Loran coordinate you have for the same spot. Figure out what the offset is (+ or - .xxx or whatever it might be) andin the menu for Loran you have to put in the chain number, then you can program in manual offsets. Plug in those manual offsets, convert back to Loran, punch in the same coordinate again, switch back and make sure it's dead on.

DISCLAIMER:

Loran is a radio wave-based system. Radio waves are affected by heat. On any given day, the same Loran coordinate could be off by many yards, so if you roll up on your spot and don't find it, do a spiral search until you've exhausted a good search pattern. 

Hope this helps. If you need someone to convert numbers for you I can always help do that too!:letsdrink

Bob


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## flrockytop (Oct 3, 2007)

> *Tuna Man (4/8/2009)*Go out there with both a GPS and Loran. If converting FROM Loran, mark spot on GPS. Crossover conversions are close, but not as precise as being on top of the spot.
> 
> 
> 
> http://www.andren.com/features.cfm




I have used this program ever since the guy fist came out with it. That was before GPS. After I got GPS I tried the conversion thing. It was not close enough to find most spots, however, if you did like others have said: take a know spot and figure out the asf? offset, it did a good job making the conversions for anything within about 2 miles. Farther than that and you need to make the conversion again.



That was one of my main reasons for going fishing on the 16th. I still have a bunch of loran numbers I've never converted to gps. All of these spots are pre-IVAN. 99% of the artificial stuff is gone but I had a lot of small single rock natural bottom spots. I checked out about 8 of them. After 15 years the loran number were still dead on. As soon as I pulled up on the loran number the bottom machine would light up. Of course there was nothing on the spots but red snapper but that is another story.



My loran is not exactly portable but if someone wanted to use it for a couple of days to find some old numbers that could be worked out.


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## inshorecatch (Oct 1, 2007)

> *Tuna Man (4/8/2009)*Go out there with both a GPS and Loran. If converting FROM Loran, mark spot on GPS. Crossover conversions are close, but not as precise as being on top of the spot.
> 
> http://www.andren.com/features.cfm
> 
> I also use the andren program


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