number conversion

What a mess · Post by **What a mess** » May 10th, 2007, 9:44 am

I have access to a map that was given to a guy next door when he bought a boat.

It has numbers written on it but they are for loran is there a way to convert these to gps?

I know you can take a couple of days and ride around with a loran and gps and do it the hard way what I was hoping was to be able to do it while on the hill.

Any ideas?

Thanks WAM out

Post by **Barhopr** » May 10th, 2007, 10:03 am

I've never had any luck w/ converting numbers then trying to find spots. The best way to do it is the hard way. It's very time consuming when your out in the Gulf goofing around trying to find a spot that has been converted.

Post by **wevans** » May 10th, 2007, 10:08 am

I haven't tried it yet BUT, this is the Coast Guards conversion program

http://www.rdc.uscg.gov/Misc/POSAID2/ta ... fault.aspx

DWilliams · Post by **DWilliams** » May 10th, 2007, 11:24 am

Posiad 2 will get you from a .1 to .2 miles. Andren will get you 100-500' unless you take some readings to calibrate. It also depends on the type of loran used and how hard the wind is blowing.

Post by **MudDucker** » May 10th, 2007, 1:46 pm

DWilliams wrote:Posiad 2 will get you from a .1 to .2 miles. Andren will get you 100-500' unless you take some readings to calibrate. It also depends on the type of loran used and how hard the wind is blowing.

I did conversions several years ago. The conversions would get you in the vicinity, but that's all. Loran was based upon radio waves and radio waves bend when they encounter magnetic fluxes. I can tell you, there are a LOT of magnetic fluxes in the big bend area.

Post by **Just Fish** » May 10th, 2007, 1:59 pm

I am looking at doing the same and I have found that most GPS units will do it for you but you have to make sure you set the appropriate Loran Chain. Look on your GPS for a Loran TD setup and or read your manual.

But even with this conversion its my understanding that its still not very acurate. So best to doublecheck with your loran running live.

DWilliams · Post by **DWilliams** » May 10th, 2007, 3:12 pm

If you are using your gps with loran tds 7980 is the chain. The offset I've been using is -1.7/-1.4 with a garmin. The offset is for the magnetic variations and the magnetic variations will change every few miles. The above offset is about 3 miles SE of K tower on the coast guard plane that was talked about on wrecks in the gulf. If you buy the andren software then you'll need to buy a loran also and take a loran reading every couple of miles to calibrate the program over the standard offsets.

Converting loran numbers is an art with lots of patience. Even with a loran on the boat Loran it still is not accurate ~200' will get you close.

KFulater · Post by **KFulater** » May 10th, 2007, 5:27 pm

My standard horizion cp 180 gps converted my 200+ numbers with no problem. It just took me about 3 hours to do and so far every # Ive been to have been within 50 ft.

Post by **Just Fish** » May 31st, 2007, 10:18 pm

I have noticed that the precision when using Loran TD on the garmin units is only within about 50-100ft. You can notice this by zooming in all the way to the 10ft range and moving your cursor. You will see that the loran numbers do not change unless you move the cursor 50-100 ft.