CHANGING LORAN TDs TO A LAT~LONG CONFIGURATION
May 02, 2013 at 5:59pm
~ Captain Paul's response to: ~ No Mo Money ~
There are several commercial programs that can convert Loran A TDís to a Latitude Longitude format, but the U.S. Coast Guard Research and Development Center had a program they call Position Aid. It is no longer available, but a US government, public domain program is available from the International Loran Association home page at http://www.loran.org/
Go there to download http://www.loran.org/gptotd.zip
It appears to be the old USCG Position Aid program. You can download the program and keep is in your computer as a fail safe conversion program.
You may find others by searching the internet for such a conversion program.
But the easiest way is to let your GPS do the conversion for you.
Almost all modern GPS units have a Grid Format called Loran TD or maybe just TDís. First turn on your GPS and go to the main menu.
Go to the Configuration or GPS setup menu or what ever your unitís manufacture calls the configuration setup for the GPS unit.
Find the POSITION FORMAT or in some cases it is called LOCATION.
In the Position Format box, Select the 'TD' mode, Then enter the Loran coordinates you want to convert to lat-lon one at a time. Once you have entered the points, go back to the Configuration menu, choose 'Position Format' again and change the format back to your normal 'Latitude-Longitude' setting. All of your waypoints you entered as TDs will now be in the lat-long format.
The Position you stated is in H,DDD,MM.mmm, ie. Hemisphere, Degrees, Minutes and Thousandths of minutes, It is the most common used in GPS units for both land and on the water. A one digit change in the last position of the decimal minutes (.00X) equals about a change of 6.2 feet, which is way below the accuracy of a standard consumer GPS unit.