Newbie Help - Or is my Etrex broken! :)

[+dysentry]

Hello Guys,

 

I have been following Geocaching for a long time, and I only just got hold of a GPS unit (thank you hire purchase!) Its a basic Garmin Etrex (yellow).

 

Well the story goes, I have been on two geocaching trips, both attempting to find two local geocaches, however, I am getting a bit confused as to what my Etrex is doing!

 

The first geocache I find, once I walk to the area (which is a feild next to a motorway) I get a good signal, but poor accuracy - 60ft. I take a step forward, then same good reception, the accuracy drops down to 20ft, next step - it jumps back up to 60ft! Every so often it would also point north, then swing and point south when I was walking straight ahead.

 

I know that you need to be moving to get accurate compas direction on the gps, but is this the same for accuracy - like should I be running round like a headless chicken trying to decrease the accuracy?

 

I eventually gave up, mainly due to the fact I had to constantly jump and run across a small (not busy) motorway trying to find out which side the cache was stashed on. But I have vowed I will return!

 

If anyone could give me a few good tips on how I can use my Etrex to be slightly more accurate - in the sense it the pointer(compas) doesn't swing north&south or east&west seemingly randomly. It would be much appreciated

 

Thank you guys, this hobby has got me out of my computer chair!

[+Bluespreacher]

quote:

---

Originally posted by dysentry:

Hello Guys,

 

I have been following Geocaching for a long time, and I only just got hold of a GPS unit (thank you hire purchase!) Its a basic Garmin Etrex (yellow).

 

Well the story goes, I have been on two geocaching trips, both attempting to find two local geocaches, however, I am getting a bit confused as to what my Etrex is doing!

 

The first geocache I find, once I walk to the area (which is a feild next to a motorway) I get a good signal, but poor accuracy - 60ft. I take a step forward, then same good reception, the accuracy drops down to 20ft, next step - it jumps back up to 60ft! Every so often it would also point north, then swing and point south when I was walking straight ahead.

 

I know that you need to be moving to get accurate compas direction on the gps, but is this the same for accuracy - like should I be running round like a headless chicken trying to decrease the accuracy?

 

I eventually gave up, mainly due to the fact I had to constantly jump and run across a small (not busy) motorway trying to find out which side the cache was stashed on. But I have vowed I will return!

 

If anyone could give me a few good tips on how I can use my Etrex to be slightly more accurate - in the sense it the pointer(compas) doesn't swing north&south or east&west seemingly randomly. It would be much appreciated

 

Thank you guys, this hobby has got me out of my computer chair!

---

 

First off, it's not your Etrex. It's just the way it is. (kinda sounds like Zen, huh?) Often the satelites are not aligned in a real good way, then you are in and out of tree cover... It goes down hill from there.

 

Thing is, GPSr's only give good directions when you are moving. As you circle around, following the arrow, the GPSr updates - slowly. Try to keep a steady motion for a time. Watch the distance reading -- are you getting closer? Sometimes you may have to do this more than once. Sometimes, you might just wait a half hour or so, maybe the sats will be in better positions. Try turning off the 'Battery Saver' option, too.

 

Just keep on caching, you will soon get a good feel for what the Etrex is doing.

 

Bluespreacher

 

"We've got the hardware and the software, the plans and the maps ..." -- Citizen Wayne Kramer

[+dysentry]

quote:

---

First off, it's not your Etrex. It's just the way it is. (kinda sounds like Zen, huh?) Often the satelites are not aligned in a real good way, then you are in and out of tree cover... It goes down hill from there.

 

Thing is, GPSr's only give good directions when you are moving. As you circle around, following the arrow, the GPSr updates - slowly. Try to keep a steady motion for a time. Watch the distance reading -- are you getting closer? Sometimes you may have to do this more than once. Sometimes, you might just wait a half hour or so, maybe the sats will be in better positions. Try turning off the 'Battery Saver' option, too.

 

Just keep on caching, you will soon get a good feel for what the Etrex is doing.

---

 

Thank you! I knew the chance of it being the GPS where slim, and chance of me doing it wrong high!

 

Doh i have had battery save on! What does it actually mean when it is on? Im guessing it doesnt 'listen' (if thats the correct term) to the sattelites as often in a period of time?

 

Thank you

[+apersson850]

In Battery save mode, reception is turned on, position measured, and then the receiver is turned off for about three seconds. Then it repeates itself again.

In normal mode, measuring runs all the time, with position updates every second. Gives more stable readings.

 

With GPS units without megnetic compasses, like yours, you can use this method near the cache.

Check the position of the cache. Remember the position (write it down if necessary).

Look at the position display on the GPS, not the navigation screen. Walk in N/S direction until you've aligned the last decimal digit (well, depending on the position format you use) of the latitude. Now, start moving E/W until you've aligned the longitude with the position you search for. Recheck that you didn't drift away from the latitude, otherwise correct a little in N/S direction again. When you are at the right position, stand still for a little while, with your GPS flat and held out in front of you. If the position seems reasonably steady, forget about the GPS and start looking. If not, adjust your position a little, N/S or E/W, or both in succession, as needed.

 

Happy hunting!

 

Anders

[+Ellteejak]

I have an Etrex Legend and I seriously think the Etrex could be off by 60 feet south of the actual waypoint. I have emailed Garmin (who looks like they actually read email, and actually respond intelligently to them) and I am awaiting a response.

 

I had not heard about the Battery saver function and I will be turning that off tonight.

 

Also consider a FIRMWARE upgrade to your Etrex. garmin has this software upgarde on their web site. Basically you download the software to your PC. Connect your Etrex to your PC, and then upload the new software to your Etrex. Try www.garmin.com

 

The best way to use the GPS seems to be to get a bearing when close to the waypoint (degrees direction). Then get another different bearing by walking 90 degrees away from your current location. Then use your compass to triangulate the point. Use this if you have no success at a direct walk to the waypoint.

[+Ellteejak]

Make sure your DATUM is correct. You need to know what this means.

 

It is nice to make sure that your Garmin is set for true north, not magnetic north. But you need to check.

[+apersson850]

Well, the eTrex, or any other, could be 20 meters off in any direction, now and then.

 

Upgrading the firmware will not help, since what was described is just as it is, sometimes. Waiting for a time with a lot of satellites spread over the sky improves the situation a lot, on the other hand.

 

The idea of getting bearings from different positions, then triangulate to the cache, is good only if there is no good reception at the cache. If there is, use the "matching the position" approach. It's better and easier.

 

Setting the datum is certainly important, if you are keying in the coordinates by hand. Load them via EasyGPS and the serial cable (provided you have one, of course?). Then you don't have to bother. Otherwise, you must set both the lat/long format to "ddd mm.mmm", not "ddd.ddddd" or "ddd mm ss.s". The datum should be WGS 84.

 

Finally, you can set the GPS to magnetic or true or grid or user-whatever-you-imagine north. As long as you don't involve maps or separate magnetic compasses, the GPS couldn't care less.

 

Even more finally, give it up, ktjensen. It's not your Legend that's faulty. If one geocacher hides a cache, and he has an EPE of 13 meters, and you are out looking for it, also with and EPE of 13 meters (which is no unusual figure at all), then the combined EPE says that there is a 50% chance that you are within 20 meters, or 60 feet, of the position shown on your GPSr. Hence, there is a 50% risk that you are further away.

 

Toss a coin a couple of times, and see how much 50% is.

 

Anders

[+cachew nut]

quote:

---

Originally posted by dysentry:

The first geocache I find, once I walk to the area (which is a feild next to a motorway) I get a good signal, but poor accuracy - 60ft. I take a step forward, then same good reception, the accuracy drops down to 20ft, next step - it jumps back up to 60ft! Every so often it would also point north, then swing and point south when I was walking straight ahead.

 

I know that you need to be moving to get accurate compas direction on the gps, but is this the same for accuracy - like should I be running round like a headless chicken trying to decrease the accuracy?

---

 

If you are getting poor accuracy then it's possible that your signals are being blocked by tree cover etc. You need to have a clear path to the sky and enough satellites for good reception.

 

I'm not sure how the Etrex works, but consider this...if you are geocaching, your pointer isn't pointing to the north or south, it should be pointing towards the geocache. As you are walking towards the geocache you should be watching whatever screen points you to the geocache, not watching the compass.

 

Since the last digit of the coordinates is only accurate to a few feet, it is possible to be at the given coordinates and move a couple of feet and still be at the given coordinates. This is when you will see the pointer start spinning in other directions, since after all, if you are there, which direction is the proper direction to go?

 

At that point when your pointer is no longer helping you figure out which way to go, it's time to stop looking at the pointer and start watching the screen with the coordinates. As you move the coordinates will change. Move in the right direction and your coordinates will eventually match the waypoint. This is where a compass, handheld, not the gps compass, comes in handy in telling you which direction to move. When your coordinates match the waypoint then it's time to stop looking at the gps and start looking for the cache with your eyes.

 

I don't use a yellow Etrex, so perhaps some of the things I said about switching screens etc. might not apply exactly the way I said, but basically you should understand your gps enough to make sense of what I'm trying to explain. Good luck.

[Floridaflamingo]

Updating the firmware on my ETrex helped considerably. And my dear sister taught me to use the co-ordinates instead of the arrow and messages when I'm getting close. That helped a lot too.

[+dysentry]

Thank you very much guys! I really appreciate your help, and realise that you have probably answered the same question for a dozen dozen Newbies Thanks for having the patience to answer me

 

It appears that it was Battery Save mode that was causing all the funny directions and coordinates.

 

All other comments have been noted, and they without doubt help me find my first two elusive Geocaches

 

Thank you.

- Stephen

[MyBoys&Me]

Also new, just got our yellow "thingy" (still waiting on PC cable from bluelight.com). But great help here. Vet cachers are wonderful to us newbies when it comes to information. Thanks for the pointers!

 

"Men are what their mothers made them." - Ralph Waldo Emerson

[+unclerojelio]

Once you get to the cache area, PUT THE GPS AWAY! Caches are found with your eyes and extensive use of THE FORCE. Just start looking around for the places where YOU would hide something. If there are two rocks stacked on top of one another, check it out. If the grass seems pushed down or trampled in one spot, check it out. If you see a suspicious cord running up the side of a tree, check it out.

 

My gps NEVER reads out zero once I've found a cache. If it did, this game would not be any fun.

 

... Two roads diverged in a wood, and I--

I took the one less traveled by, ...

 

unclerojelio

[+W8TVI]

quote:

---

Originally posted by unclerojelio:

Once you get to the cache area, PUT THE GPS AWAY! Caches are found with your eyes and extensive use of THE FORCE. Just start looking around for the places where YOU would hide something. If there are two rocks stacked on top of one another, check it out. If the grass seems pushed down or trampled in one spot, check it out. If you see a suspicious cord running up the side of a tree, check it out.

 

My gps NEVER reads out zero once I've found a cache. If it did, this game would not be any fun.

---

 

when my GPS says its zero I start looking

thats when I'm within about 13 to 30 feet of it depending ot the treecover

 

Noel