Loran Or Gps?

[Speargun]

I've noticed a lot of people are still using loran on the board. (and everywhere else).
Why?
I understand that it has been in use a long time and that if you get your numbers from an "old timer" :D that's how they have them in thier little black book. With GPS now readily available, how come loran is still so popular?
Also, is there a good program out there to convert loran to gps? I know that there is going to be some error, but since I don't own a loran getting close is better than not getting there at all.
Jeff......

[richhermes]

Most people that do have both loran and gps are slowly converting the loran numbers to gps coords. by navigating to the spot via loran and then saving the waypoint in the gps. Eventually you should have all your old Loran numbers converted.

If you figure in the added error in the conversion process and the accuracy of loran in general. I would think your error would be so great that you may not be able to find the small spots you have marked, if you went by mathematical conversion alone.

Then again, I may not know what the hell I'm talking about and this could all be wrong!

[kitefisherman]

Rich is right. The best way to convert is to find the spot with your Loran and then mark it with your GPS. I realize that this doesn't help you much if you don't have a loran. The loran to lat/lon conversion program that is built into my Garmin GPS isn't worth a shit IMO. It has been off by hundreds of yards when we used it up in Stuart. Although I haven't personally used it, I understand that the US Coast Guard has a pretty good conversion program (as far as these programs go) for free at http://www.rdc.uscg.gov/rdcpages/soft-posaid2.html. A more user friendly program is available through Andren Software(www.andren.com) for under $100. I have not used either software but both were mentioned in an article on this topic that appeared in the July 2002 issue of Florida Sportsman.

[inletsurf]

You're right Rich.

You can do a couple of other things. In our area, there's a guy named Carl (Andren) who developed his own Loran-to-GPS conversion software with the proper offsets built into the system. This alone helped us get our numbers to within 150 feet or less.

However, an easier way to get closer is to have both a loran and GPS. Find the spot on the loran, mark it with the GPS. Go to the GPS menu and convert lat-long cood's to TD #'s equivalent. Then compare the offsets from the Loran numbers to the TD #'s. There should be a spot in your GPS menu to enter offsets. Enter those offsets to bias the original GPS TD# to the true TD#. We have used this method in conjunction with the above software. However after entering the offsets, you can enter a new raw Loran number and the GPS will be pretty close, we have found around 50 to 100 feet. Simple scrubbing of the area and proper re-marking will get you back to normal.

Keep in mind that the offsets are good ONLY for a general area. Don't expect the offsets out of New Port Ritchey to work down off of Venice. The change of Loran signals and interferences is not linear. Hope this helps.

PS Carl Andren lives here in this area. My dive captain knows him quite well and has used his program and the offset routine to get us rather close. Andren's program alone will get you within "scrubbing" range of the mark. I recommend his software, since entering any GOOD Loran number has resulted in our success.

[slippery chicken]

You do not have to go from tarpon to venice to have the corrections be off, just travel a little distance and you are off again. The only way to convert #s is by going to each one with loran and then write down the # that your gps is saying. IF you are looking for the large areas fo hard bottom that everyone knows about, the converted number will get you in the neighborhood, maybe. If you are trying to find those 1'-2' ledges that are only 100' feet long off converted #'s you are waisting time and fuel. Once again, just my opinion, Rick

[inletsurf]

Chicken

I agree that the method you describe is the BEST method for locating a mark, however most boaters these days do not have Lorans.

What we have done was take a sample of each end of our general dive area (from Port Canaveral to Upper Waters of Ft. Pierce) and figured offsets of each using a Loran system.

Now we don't even need the Loran. When we enter a number (most of our numbers are 1' 50-100 ft long ledges ;)) we find it usually within 50 feet, sometimes further out. Thanks to a nice mapping GPS we have never spent more than 10 minutes of trolling speed fuel to find the spot. Usually it's not even 5 minutes.

I know you probably adhere to your opinion strongly, I'm just telling you there isn't a number I haven't found yet using this method. However, the method I described will work for people who don't have a loran and can "borrow" the determined locale offsets from others. I guess if you can't get the offsets, you're screwed w/o the Loran anyway.

Now you have me sounding like ****ing Gman ...:D
just kidding. Using the Loran-GPS method you stated is obviously the best way.

[Cock's Roost]

While I agree that the best conversion is using the loran to get there then pressing save on the GPS. Still we have an old Admiral GPS that is surprisingly accurate with the conversion. Plus with the thought that one day Loran might not be there you need to get all your old numbers converted in case they faze it out.

[Speargun]

....Speaking of loran, can you even buy them anymore? I don't remember seeing any at any of my local marine dealers. If I found a good deal on one (read real cheap ) I would buy one just to avoid the headache of conversion.

The reason for this thread to start with, was a friend gave me some of his old charts out of Crystal River & St. Pete with a bunch of spots marked and his "little black book" with a ton of numbers.
WHOO HOOO!!
Now I just need to find the spots & see if there is anything worth shooting on them.

[inletsurf]

I've seen them go for about $30 on ebay.

[Cock's Roost]

Furuno if that is spelled correct, has a model they sell. Cant beat the old king Loran's if you can find one.

[dabulltrouble]

hey speargun.i have a loran and live in the crystal river area.i,ll convert your # for you anytime you want to go do some shootin

[greyface]

Great topic, great thread! One day, I'll get a GPS, but I still just love my $175 Sea Mate. Hey, any of you fellers old enough to have seen/used a loran "A"? :rolleyes: Talk about a crap shoot! My Uncle had one on his grouped boat, back in the mid '70's. We used to fish the Dry Tortugas, out of Pine Island/Ft. myers. Damn thing was as big as a suitcase. Had a little t.v. screen w/ a shroud that you put yer face up against. You had to toggle & line up the master & salve signals, then flip another switch to give you yer #'s. Inherently inaccurate, Uncle hated them, never used them. Off of Rebecca Shoals, we "checked" our position. Damn thing had us in downtown Havana!(almost:p ) My Uncle just used dead reckoning, with unreal success.

[Divin' fool]

I've used the USCG conversion program (I think they call it POSNAV). It TOTALLY SUCKS..... I had some numbers be as far as 100 miles off!!:rolleyes:

[Screen Name]

Speargun ;) .

I have my Andren program pretty well calibrated. I've got a lot of confidence in the way you calibrate it. You take loran and GPS readings at several of spots and enter those as calibration readings (actually as many as you want). Mine is now spot-on. Its a handy way to organize your numbers too.

The program "out of the box" is no more accurate than your GPS when you try to go to a loran #........maybe half mile. The coast guard ASF's never worked for me either. A calibrated Andren program is the ticket. Carl Andren used to be a member of SPUC when he lived over here, and his program is reccomended by the Coast Guard.

A friend of mine in the SPUCs, Dennis O Hearn, is coming out with a new program called "Offshore Hunter" which also promises to be good. Dennis, if you read this, show us your program dude! :D

By the way Speargun, just email me all your numbers and I'll send you back the GPS equivalents after I load them all into my database......:D

[Speargun]

Posted by dabulltrouble
hey speargun.i have a loran and live in the crystal river area.i,ll convert your # for you anytime you want to go do some shootin
Posted by Screen Name
By the way Speargun, just email me all your numbers and I'll send you back the GPS equivalents after I load them all into my database......

....Man! There sure are some nice people on this board! Just imagine, two guys willing to spend their valuable free time converting my old loran #'s into lat & lon. I bet they would even drive to each & every spot just to make sure that they had the right #'s and there were fish there. I know they wouldn't want me to waste gas going to a spot that didn't have any fish on it.

dabulltrouble, Screen Name, the numbers are in the mail. :D

[dabulltrouble]

hey speargun.i meant if you ever want to get together and do any shootin we could take my boat and you could jump on board with some of your #s and we could check them out.i really dont need any more #s,got more than i,ll ever dive now

[Screen Name]

Email me those numbers you'll never dive. :D

[FredT]

Loran is much more repeatable than GPS, provided you are using the same loran box. GPS has a better box to box accuracy, but less repeatability. Those with good loran numbers for their box can find a site within about 25' while box to box can be in the 150'-300' accuracy range. The GPS is good for about 100' box to box, but has the same accuracy on the same box day to day. DGPS, if a secondary transmitter is available, can bring absolute accuracy down to less than a meter. Regretably DGPS is pretty useless when far out to sea and out of range of the reference.

Since the USCG is looking forward to the rapidly approaching day when they can turn off the loran transmitters (and save a bunch of $ even by government standards) conversion of the loran numbers into something else is necessary now. If you have a lot of numbers, convert the small sites and confirm the conversion with a site visit first. Larger structures can be found using your sonar even with some location fuzziness if the USCG "flips the switch" before you finish the conversion process.

FT

[Speargun]

Between yours & Screen's posts, I just had to brake your balls. :D
I'm with SN, "Email me those numbers you'll never dive." :D :D
Seriously, this has turned into a great thread guys. I've picked up a lot of good info.

I think I'll start a new thread....
POST YOUR NUMBERS HERE!
...think I'll get any responses? :cool:

[Nxs Diver]

Speargun, Here's how we convert #'s. When I lost my dad back in 1980, He had 3 books full of numbers from the middle grounds to marco island.He had 2 si-tex lorans(which still work great). When we go to a number in loran and dive it, we send up a float on either the sweet spot of the ledge or a wreck or what-ever we want to mark. Then take the boat and take the slack out of the line untill you are straight up and down, write the number in both 14000 and 40000 time delays and lat lon. Next time you go back you don't even need to run the bottom machine. As for as finding a used loran try www. natucial trader .com they sometimes have used ones but make sure you get a coupler . good luck. I hope someone comes out with an acurate program before they turn the loran off I still have alot of numbers to convert.

[dabulltrouble]

hey screen,you dive up this way much,if you do i will send you some #s.havent dove any of them so i cant confirm whats on the bottom,cant send you the ones i dive.i,ve seen the size of some of those fish you shoot.cant have you up here on my best spots shootin everything.

[100days-a-year]

A WAAS GPS costs start at $250.They are the most accurate commercially available nav system in the world.LORAN repeatability is also tied to crossing angle of lines.LORANs absolute repeatability is also tied to the angle .Finding a spot that's visible(a rig,tower or even a wreck with bait all over it)is much easier than finding a piece of airplane wing or other small junk.I have 2 lorans,a differential GPS and a back-up handheld GPS.This time of year it's easy to go anywhere you want dive.When it gets warmer I break out the old loran book and start converting more #s that are smaller,less visited marks.To many knuckleheads on the published or easily found stuff.The offsets trick works on easy stuff,but the offsets change every 5 to 10 miles.I've actually seen people anchor up on bait marks out in the sand cause thier GPS said the were there.

[richhermes]

There are only two WAAS satellites in orbit right now. One on each coast. On a 12 channel gps with WAAS enabled, 2 channels are reserved for WAAS reception whether you are receiving data from those satellites or not. I have sometimes seen my accuracy decrease with WAAS enabled because of this.

[ICEMAN]

I use D-GPS, WAAS-GPS and a Loran.Screen Name's Loran Conversion suck's.In never was able to find one of his hot #.
On a not converted # i use my northstar and go 50-80' to the NE.Florida West coast 14-45 line.I use my loran for the E-coast and back up on the West Coast.

[Screen Name]

ICEMAN, what you whippin on me for Bud! I'd give you some crap but I'm afraid you would make me dive my numbers! ;)

Dabull, dont let the pictures scare ya, I'm really a puss with photoshop. Sometime I'd like to go diving with ya..........I got a feeling ICEMAN is gonna show me a lot of dirt this year. I might need a break and dive some structure. :D