Old GPS

[freddogs]

:cry: I have an older Magellan GPS and it seems to be a bit off at times.Other times it works OK.
I was up in Northern Wisconsin a few weeks ago. I built a ground blind on a ridge and made it a landmark. I turned the GPS off and then on again. When I went to goto it said I was .3 miles away from the blind I was sitting in. Is my GPS wearing out or is this just an error from being an old model?

[coug2wolfs]

Jeepers!  I didn't realize GB already made this here GPS section, I better gitta work :wink:

First thing you do is get that puppy OUT of English mode and switch it over to Metric.  You want to do this BECAUSE, all the grids on the Topo Maps are marked in 1000 meter grids.

When the Government was scramblin the signals we were on a good day lucky to get 100 meter precision.  I did in fact have a "discussion" with them Federal boys a while back.  They were concerned that an "enemy" could use a GPS to guide a Nuclear missle!  Like I told em, Guys, IF a nuc is 100 meters off it's STILL ground zero!  Gona vaporize ya just as good as if it landed on ya.  They musta made some sense on it cause now we are 5 to 7 meter precision on the average day.

Anyway, to your question.  Believe there are 24 satelites in total. We get 12 at a pop on account of the rest are on the other side of the planet and we can't get at em.  Of the 12 in THIS hemisphere, sometimes you get 12, sometimes you don't, dependin on where you are and what's blocking them.  Things like the horizon, mountains.....

The strongest signals come from the ones that are 45 degrees to the horizon, stronger yet, the ones overhead.  A lock on two satelites won't do a danged thing for ya, gotta be 3 minimum.  The accuracy comes from triangulation.  Now if the 3 are close in the atmosphere, sometimes, there isn't enough distance to get a good fix.  If you let it set there for a spell another satelite will come into view and you'll see a big difference.

I have had as many as 5 units on at one time doing a stare and compare.  My low end garmin Etrex locks up the fastest, but my high end Vista is the most accurate and is a bit slower.

Shoot me your numbers (UTM) and I'll see right where you are :lol:

Coug

[volshooter]

I have an older Garmin but didn't use it much because it would not take me to the exact tree my stand was in under darkness. Just what degree of accuracy is normal? On the bigger scheme (wildlife management area) where miles are involved it worked great. Did I expect to much...I expected it to take me within 20 yards of my tree, I got about a 50 yard accuracy, which in the dark is a looong way off.
Rick :shock:

[Hud]

Mine does that too and it is a older one. I think that they didn't have to make the older ones that accurate as the signals used to be scrambled a little bit anyway.  

They no longer scramble the signals.  So the newer ones are made to be more acurate to take advantage of the "unscrambled" signals.

Mine is still close enough to get me back to camp.

Hud

[TedTF]

What units do you have?  Garmin offers free software updates on their website to improve accuracy

[kamml]

I have an older Magellan 2000XL that was the same way.  The first time I used it on a search and rescue drill I was very surprised it ran me in a circle around a known location without ever indicating I was at the location.  Frustrating to say the least and somewhat disappointing to me.  This was back in the early days, I think 95-96 when GPS was touted as the coming the thing.  Actually it was right on the money, my assumption was off, it got me very close and I just didn't know it.  It was a similar distance, 2-3 tenths of mile.  Good thing I wasn't lost, I would still be there looking for the exact pinpoint location.  And my estimated error was around 66 feet if my memory serves me.  Ken  

[darrell8937]

Gps accuracy.. varies due to the number and quality of the Gps Signal. even new ones may only get you to within 60-80 feet of target if not more. May be difficuilt to finad a specific tree. GPS signals are downgraded to insure someone does not use it for accurate guidence of some missle etc. They generaly get you only close. In the dark , 20 feet seems like a mile.

[daddywpb]

My Garmin Etrex and Legend will both guide me right into a tree in the dark. From the posts here, I guess the older ones were not as accurate. Maybe you were in a place where the signal was blocked from overhead cover, etc. I'm not sure about the older ones, but the new units can and will guide you directly to a specific tree in the dark.

[Siskiyou]

:cry: I have an older Magellan GPS and it seems to be a bit off at times.Other times it works OK.
I was up in Northern Wisconsin a few weeks ago. I built a ground blind on a ridge and made it a landmark. I turned the GPS off and then on again. When I went to goto it said I was .3 miles away from the blind I was sitting in. Is my GPS wearing out or is this just an error from being an old model?

There are all kinds of variables for this one.  (1) What model # is the OLDER Magellan?  The first handheld recreational GPS unit I ever messed with was a 2-Channel model.  We messed with it some but did not consider it accurate enough for our work.  After messing with the old 2-channel unit I lost interest in gps units.  Recreational GPS units took a step forward when Magellan and Garmin started to produce 12-channel models.  The largest number of satellites I have received are nine or ten.  The average number in an open forested area are six or seven.

(2)  Manufactures websites normally offer software upgrades for those units designed to connect to a PC.  I believe that my Garmin Legend has improved in performance and capability from Garmin's operational software upgrades.  I recently upgraded a Legend for another person.  It is no big deal and again we were able to see some benefits.  My Legend came from the factory with the ability to hold 500 waypoints.  A factory software upgrade increase that number to 1000.  I believe the upgrades have also improved on how the unit process signals from satellites.  It seems to receive more satellites, and has stronger signal strength.  It out performs a GPS72 which is suppose to have a better antenna.  The GPS72 has never had it's software upgraded.

(3) Faster PROCESSORS along with update internal software allows "some" of the newer model to obtain satellites faster, and draw data on the screen faster.  At the same time battery life has been extended.

(4)  Back to the question-----.  I have read the method some of the older Magellan models process information placed them at a disadvantage from an accuracy stand point.  I do not believe this is true of the later models.  IN FACT,  many Magellan models with Helix antenna's outperform Garmin's Etrex units with a patch antenna on government test courses.  There are some Garmin models offered with Helix antenna's.  Working or playing in heavy cover, buy a unit that takes an external antenna.  I have thought of purchasing an antenna, but I am not sure that it would be worth it.  Normally I receive an adequate signal in most areas.  If I was up in the bush country or in the jungle I might change my mind. ( The "bush country" and the country up around Rhinelander look about the same.   And they are both cold.  It was -41 degrees when I was in Rhinelander.  Hmmm, could the could weather effect the power level in the gps receiver?)

(5)  Satellite reception varies at the same location because of the number of satellites that are available on a given date and time are always changing.  Do not expect the same reception at a location on November 1st, as your received on October 1st. at the same time of day.  Sometimes when I am out hiking with my gps I will stop and pull my gps out of the pouch.  I will give it a few minutes to see if I can pickup additional satellites.  Numerous times I have succeeded in picking up a couple more satellites.  This might help in tying down a sight when you are getting close.

(6) The big change in civilian gps accuracy came on May 1, 2000 when a Presidential Order went into effect to shut off selective availability.  This degraded the signal that civilian gps received.

freddogs what is the model number of the unit in question?  I will do a little research on it.

[S.B.]

:cry: I have an older Magellan GPS and it seems to be a bit off at times.Other times it works OK.
I was up in Northern Wisconsin a few weeks ago. I built a ground blind on a ridge and made it a landmark. I turned the GPS off and then on again. When I went to goto it said I was .3 miles away from the blind I was sitting in. Is my GPS wearing out or is this just an error from being an old model?

.3 miles is a far piece for something that costs what these GPS's cost? I've got an older Garmin III and have never experienced that kind of problem? Maybe get in touch with the manufacturer?