TD! TD2 to Lat Lon????

[LastMate]

Ok I feel kinda like a retard asking but I cant figure this one out. How do you go from reading Lat Lon on your GPS to TD1 TD2. I have tried every different setting I can think of on my garmin but cant figure out how to get it converted. It would open so many more dive sites if I knew how. Let me know if any of you might know what to do!!

 

[MRXRAY]

TD1 and TD2 refer to LORAN coordinates. 99% of GPS units will not provide LORAN Coordinates! Loran uses land based "Radio Towers" for "Rough" coordinates. I say rough because the closer you are to land the more the system will fail to give you an accurate reading.....Thus the name Long Range Aide to Navigation. Until the advent of GPS (Global Positioning Systems) which uses multiple Satellites to provide very accurate positioning Loran was the best we had, but that is old technology but is a good backup. If you are using Loran for water navigation (Airplanes still use it successfully) take it to the pawn shop with your Beta recorder and sell it. On the other hand if you have a GPS unit but were given Loran Coordinates then just find a different site that lists GPS (Lat Lon) Coordinates instead. If you have some secret Loran spots that you need to convert to GPS so you can find them then try this software:

Andren Software - LoranGPS Loran GPS Conversion Software, Plot, Map, Upload your coordinates to your GPS directly.

or this Public Domain Software (Free) a link is on this site:

International Loran Association - Coordinate Conversion Information

Good Luck!

Ok I feel kinda like a retard asking but I cant figure this one out. How do you go from reading Lat Lon on your GPS to TD1 TD2. I have tried every different setting I can think of on my garmin but cant figure out how to get it converted. It would open so many more dive sites if I knew how. Let me know if any of you might know what to do!!

 

[LastMate]

Thanks for the info!!!

 

[MRXRAY]

No Problem!

 

[MRXRAY]

Those 6 years doing Navigation on a Submarine finally paid off! Your tax dollars at Work!

 

[Charlie99]

The Time-Delay to Lat/Long programs often have sizeable errors.

If you have a nearby easily located point, such as a channel marker, that you also have Loran time-delay numbers for, then crank those through the conversion program and see how much of an position offset there is between the calculated lat/long, and the lat/long as measured by your GPS.

If you don't find the dive site when going to the converted lat/long, apply that same position offset and look there.

 

[MRXRAY]

Good point Charlie99! The TD to LAT/LONG converters usually have an inherient offset to them, if you can determine that offset as Charlie99 mentions you will be much better off! The best option is still to use someone elses GPS cooridantes for a known site.

 

[LastMate]

I have a garmin GPS and its pretty close to most of the time. I can hit a spot within 2 or 3 loops with the boat. But thats only due to the number not being right on. I have a log with over 1000 TD1 and TD2 spots but cant use them.

 

[Hetland]

Are they public or private spots? There are hundreds and hundreds of published dive/fishing spots in our area available on the internet.

Unless the numbers you have are super-secret, it might not be worth converting them. If they are stale, then it's a good bet that the bottom material has shifted anyway, which will make it that much harder for you to find the spots.

 

[wjefferis]

Check out this link to the MBT Divers website. They have a bunch of dive sites with both the LORAN and GPS numbers for them, hope this helps GPS Numbers