My dad gave me a black marble book full of old loran C numbers that need to be converted. My question to y’all is what and how do you convert them over to workable GPS numbers. My old loran C brain just died so that’s not a option thanks in advance for your help.
Just e-mail them to me and I will see what I can do!
Many ways to do them; most ways are very tedious. I can convert them into GPS format and put them in an electronic file that your GPS can upload if it has a card reader or can plug into a PC. My conversions are usually within 60ft for TD’s with one decimal place. May be able to do better if your TD’s have two decimal places and some wrecks or other pinpointed spots spread around to calibrate and adjust for the particular Loran box the numbers originally came from.
It takes some knowledge of the areas offshore and how the TD’s have changed a bit over time to get them close enough to be better than just running compass headings and distances to find the same stuff. What most people are able to do is get them down to a couple hundred feet, and if the TD’s were marks for large areas of bottom, they’ll get you there then. I can do better and put them into a file that your GPS unit can upload if you’re interested though.
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Phin thanks a bunch check your PM
On the garmin units, it is simple. plug in a known GPS lat/Lon number and a known Loran C number for the same spot. View on the map, you will see the offset.
Garmin allows you to add or subtract the offset number on the loran C side. Play with, and you will see the two spots come together. Once you figure out the offset, plug in all of your Loran C numbers, then tell the unit to read Lat/Lon… conversion complete.
ReelEscape on this site probably remembers the offset. It will get you within 15/20 feet.
Clinton
MadBanana
31 Fountain
quote:
Originally posted by madbananaOn the garmin units, it is simple. plug in a known GPS lat/Lon number and a known Loran C number for the same spot. View on the map, you will see the offset.
Garmin allows you to add or subtract the offset number on the loran C side. Play with, and you will see the two spots come together. Once you figure out the offset, plug in all of your Loran C numbers, then tell the unit to read Lat/Lon… conversion complete.
ReelEscape on this site probably remembers the offset. It will get you within 15/20 feet.
Clinton
MadBanana
31 Fountain
I didn’t know garmin had set their new units up with that feature. Sounds very nice. The problem is that the offsets are different for two spots that are as close as 4 or 5 miles away sometimes. Inshore spots are harder to convert properly without a lot of info and calibration. Offshore spots are easier. Also, I’ve found that you cannot get loran accuracy that close unless you have a lot of information in a book that’s all from one unit originally, and that unit gave TD’s with two decimal places. Some Loran boxes were 300ft off from another Loran box. So having as much information as possible when converting and zero’ing in is very helpful. Otherwise, you are going to just get into the same general area and you end up finding a lot of other bottom while looking for the original TD marked bottom.
- www.joinrfa.org - www.joincca.org - www.southeasternfish.org - Get informed or give up fishing!
Luke 8:22-25