About | Blog | Forums | People | Free Newsletter
Trailspace is a product review site for outdoor enthusiasts. Use it to find and share great gear.

Handheld GPS - I need advice

3:33 p.m. on February 3, 2010 (EST)
14 reviewer rep
318 forum posts

I am going meteorite hunting out in the CA desert. Anyway I need a GPS to record the location of any meteorites I pick up. It is required to preserve the scientific data of the meteorites. I would also like one that can show Bureau of land management data so I will know in the field if I am on BLM Land, State Land, Private Land or a Mining Clam. I know most of the gear I want isn't even made yet. If you can point me to a GPS that has features like that great. If not I will need one that can take a computer upload. I prefer ones with a good track record and high customer approval. It should also be color so I can use color maps.

6:58 p.m. on February 3, 2010 (EST)
TOP 10 REVIEWER REVIEW CORPS
2,264 reviewer rep
5,188 forum posts

To get all the data you are asking for displayed, you will need to get one of the survey-grade GPSRs and buy the appropriate data package. Certainly, if you are truly going to preserve the data for scientific analysis (I certainly hope so, since casual meteorite hunters (and amateur pot hunters) have destroyed a lot of valuable data for their own private amusement), you will need such an instrument. You will need the capability of differential correction and post-processing. Consumer devices with their limitation of 7m @50% are not up to the task. The current issue of GPS World (Jan 2010) has a receiver survey, with the tables indicating the intended applications and performance parameters. The brands I would recommend, based on experience are Trimble, Topcon, and Leica Geosystems. The private land and mining claim data are pretty sketchy, with a large number of the owners tending to push their claims beyond the recorded boundaries and being a bit belligerent about it. Do a bit of research in the county recorder's office, and you will find a lot of inconsistencies.

8:26 p.m. on February 3, 2010 (EST)
14 reviewer rep
318 forum posts

I have been researching today. I have found some information. Most people like the GARMIN GPS 60CX. I base this on the enormous amount of positive reviews. I don't see any information on how accurate it is. I also found out you want to buy hunting maps compatible with Garmins mapsource software to know what land your on (these do not include mining claims). I think mining claims need to be clearly marked in the wild anyway. I expect a Garmin unit with color and the hunting maps is going to be $200 - $400 dollars. I will of course try to get it together for under $200.

Bill S: I did a search of the Trimble, Topcon and Leica systems I see that the trimble units are starting to use BLM data. I have not found a handheld trimble unit I can buy with BLM data yet or even a solution to get uploaded into the units.

I am going to run down to the department of the interior tomorrow and see what they are using and ask a few questions.

10:54 p.m. on February 3, 2010 (EST)
TOP 10 REVIEWER REVIEW CORPS
2,264 reviewer rep
5,188 forum posts

So now I know where you got your inspiration. I was scanning between commercials on the Weather Channel and saw there is a series on The Science Channel, called "Meteorite Men". These guys are exactly the problem I was referring to - amateur collectors who think that taking a quick fix with a Garmin RINO and carting off their finds is good enough. They have a couple positive things going for them - they did ask permission from the rancher on whose land they were trespassing (he happens to be an amateur meteorite collector himself, or more accurately, a wannabe); and they did take their grabs to a professional researcher at Univ of Arizona. But there is all this business about "secret maps" and showing USGS topos with the names marked out (as if someone could not do a quick search of one of the computerized map programs in the region of Arizona that was identified and spot the location). And the "heros" of this reality show were wandering around in 120 deg weather with a pint of bottled water, dressed in camo, with vests over their long-sleeves (yet not sweating???).

If you are really doing serious research that is of real value to science, one of the handheld Garmins does not record the positions accurately enough. Plus it was clear that the "Meteorite Men" do not really understand the limitations of their RINO.

As far as accuracy, all consumer handheld units are of equivalent accuracy. The limitation is the signal available to "non-authorized" users - 7 m radius for the 50% circle. For useful work, and not the amateur collecting that loses much of the needed information, you need a differential unit, with a source of the differential corrections and post-processing for an accuracy on the sub-meter. Yeah, I know, it's all a lot of fun, and you might find the missing pieces of the "Tucson Ring" (the goal of the "Meteorite Men" on the current episode), which would be worth gazillions of dollars - but at what cost to the real science that could be done if the finds were properly documented and studied by professional meteoriticists? And, yeah, I know, there are several hundred "meteor men" out there removing the evidence for their personal collections (and in some cases selling them through the pages of Astronomy Magazine and Sky and Telescope - which is exactly the problem.

12:00 a.m. on February 4, 2010 (EST)
14 reviewer rep
318 forum posts

I don't see a problem with taking meteorites with a regular hand held GPS unit. New meteorites are falling to earth all the time. It isn't like they are some resource that runs out. They are rare but that doesn't mean I cannot pick them up.
I am more interested in not searching on private property without permission. The reason the data is collected when you find a meteorite is so the tracking system can plot a strewn field. While it would be nice to have exact data all the time it’s just not possible all the time. That said if you want to donate me a better GPS I will take with me into the field. I am all for the best scientific data I can collect but I have limited funds. I also expect any data I bring back with a new hand held GPS is light years better then what was available a just few years ago.

I just don't get the idea I am removing evidence. It is a rock not a crime scene.

You always want to chip off a little bit of a meteorite and have the college look at it. That way they can have a sample on file if nobody ever found one before. It also helps you to identify your meteorites. They will examine it free of charge.

12:46 a.m. on February 4, 2010 (EST)
REVIEW CORPS
476 reviewer rep
283 forum posts

FYI, I own a Garmin 60CS and do a lot of geocaching. I find the accuracy to be about 6-10 feet when marking a waypoint and letting it average about 100 times. Of course this is under optimal conditions (clear view of sky).

10:14 a.m. on February 4, 2010 (EST)
27 reviewer rep
200 forum posts

So now I know where you got your inspiration. I was scanning between commercials on the Weather Channel and saw there is a series on The Science Channel, called "Meteor Men". These guys are exactly the problem I was referring to - amateur collectors who think that taking a quick fix with a Garmin RINO and carting off their finds is good enough. They have a couple positive things going for them - they did ask permission from the rancher on whose land they were trespassing (he happens to be an amateur meteorite collector himself, or more accurately, a wannabe); and they did take their grabs to a professional researcher at Univ of Arizona. But there is all this business about "secret maps" and showing USGS topos with the names marked out (as if someone could not do a quick search of one of the computerized map programs in the region of Arizona that was identified and spot the location). And the "heros" of this reality show were wandering around in 120 deg weather with a pint of bottled water, dressed in camo, with vests over their long-sleeves (yet not sweating???).

If you are really doing serious research that is of real value to science, one of the handheld Garmins does not record the positions accurately enough. Plus it was clear that the "Meteor Men" do not really understand the limitations of their RINO.

As far as accuracy, all consumer handheld units are of equivalent accuracy. The limitation is the signal available to "non-authorized" users - 7 m radius for the 50% circle. For useful work, and not the amateur collecting that loses much of the needed information, you need a differential unit, with a source of the differential corrections and post-processing for an accuracy on the sub-meter. Yeah, I know, it's all a lot of fun, and you might find the missing pieces of the "Tucson Ring" (the goal of the "Meteor Men" on the current episode), which would be worth gazillions of dollars - but at what cost to the real science that could be done if the finds were properly documented and studied by professional meteoriticists? And, yeah, I know, there are several hundred "meteor men" out there removing the evidence for their personal collections (and in some cases selling them through the pages of Astronomy Magazine and Sky and Telescope - which is exactly the problem.

Bill,

Regarding the "non-authorized" comment. I thought President Clinton did away with with selective availability in the mid-90s? Or are you referring to something else?

http://en.wikipedia.org/wiki/Global_Positioning_System#Selective_availability

11:11 a.m. on February 4, 2010 (EST)
TOP 10 REVIEWER REVIEW CORPS
2,264 reviewer rep
5,188 forum posts

"Non-authorized users" have access only to the C/A code. "Authorized users" (mostly military, but certain other government agencies and a few other users) have access to the P/Y code. At this point, non-authorized users also only have access to the code on the L1 signal, but can use L3 codeless if they have the proper receiver (mostly survey-grade receivers). Ultimately, non-authorized users (consumers, etc) will have access to the code signal on L1, L3, and L5 frequencies, enabling real-time atmospheric corrections. There currently are a small number of the 32 active satellites that transmit on all 3 frequencies, but not enough for navigation and survey purposes. No consumer GPSRs have the capability of using all 3 frequencies with the code message at this time, and Garmin, Magellan, and Delorme all have told me they have no immediate plans to do so (big cost increase at this time, and they see no advantage for the typical consumer over the better accuracy).

11:19 a.m. on February 4, 2010 (EST)
TOP 10 REVIEWER REVIEW CORPS
2,264 reviewer rep
5,188 forum posts

...I just don't get the idea I am removing evidence. It is a rock not a crime scene.

Sigh! That's what the pot collectors say, too. "It's just an old pot or potsherd (or arrowhead or spearpoint or ...) that some long-dead Indian/Aborigine/etc abandoned centuries ago". Ask the professional archaeologists and anthropologists about those pieces of "just garbage". Sorry, it isn't just "a rock". People were saying that about the petrified wood in the Painted Desert as well. Eventually, it was realized that these "just pretty rocks" were being carted off by the whole log.

5:47 p.m. on February 4, 2010 (EST)
14 reviewer rep
318 forum posts

In CA you cannot disturb any historical sites. I would GPS them and hand that information to the university if I found any. I think your confusing Meteorites and Historical sites. I think the meteorite hunter performs a useful service to be truthful. The meteorites will rust and be lost to everyone if they are not dug up and sold into private collections that will take care of them.

10:18 p.m. on February 4, 2010 (EST)
27 reviewer rep
200 forum posts

Bill,

That's new information for me, thanks. How much of that can be made up by WAAS correction?

7:58 p.m. on February 17, 2010 (EST)
14 reviewer rep
318 forum posts

I still have not found a Garmin GPS I can afford. The software for the BLM maps is $75.00 it only works on Garmin GPS. I scored a 350 lb Rare Earth Neodymium Magnet off ebay. It should work for picking up the space rocks.

8:20 p.m. on February 21, 2010 (EST)
24 reviewer rep
3 forum posts

"Yock" reviewed the Garmin GPSMAP60csx in the February newsletter. I, too, have that model and, like Yock, am very pleased with it. I wanted to let Yock and others know that (a) I have used my unit with NiMH rechargeable batteries* for several years with very good results and (b) that free 1:24M-scale topos are available at http://www.gpsfiledepot.com/. (*No matter which batteries you use, be sure to tell the unit what type batteries you are using in the Setup|System|BatteryType menu. I especially like Sanyo "eneloop" brand NiMHs. They keep their "full" charge for weeks in the drawer.)

3:14 p.m. on February 22, 2010 (EST)
27 reviewer rep
200 forum posts

Larry,

Thanks for the Topo tip. I love free maps!

The problem isn't Nickel-Metal Hydride (NiMH) batteries. Garmin documents them as compatible anyway. The problem are the newer Lithium-Ion (Li-Ion) batteries. These are the kind you see marketed towards newer devices such as digicams, digital photo frames, mp3 players, etc. When new, lithium batteries sometimes have a higher-than-spec output voltage, which Garmin claims can cause damage to the unit. I haven't flirted with lithium usage in mine to find out how dire those warnings actually are, so YMMV as usual.

[edit] I went back and re-read my review and I see why you mentioned the NiMH batteries. I inadvertantly implied that alkaline batteries were the only option for the unit, when NiMH batteries are certainly an option. I don't think I can change it, but I'll look. Thanks!

4:40 p.m. on February 22, 2010 (EST)
14 reviewer rep
318 forum posts

I am not sure if I should spend the money to get the Garmin 60CSx or save a hundred bucks and get the Garmin 60CS. The noted difference is the memory slot. The 60CS has 54MB and the 60CSx has a memory slot. Is the extra memory worth the money?

6:12 p.m. on February 22, 2010 (EST)
MODERATOR
38 reviewer rep
1,743 forum posts

Larry, I also got a free topo map of California off gpsfiledepot. Once I figured out how to use it, worked just fine.

I agree, the Sanyo Eneloop batteries are great. Mine stay charged for a long time and I've used AA's in my GPS and camera and the AAA's in my Aurora headlamp. The only drawback is when they go dead, they are dead. No dimming like with an Alkaline, so it pays to keep a rough idea as to how long they've been used. They seem to do pretty well in cold weather, too, Cold meaning around freezing.

9:27 p.m. on February 22, 2010 (EST)
14 reviewer rep
318 forum posts

These extra maps sound interesting. Do you think I would need the extra memory slot to use them?

7:44 a.m. on February 23, 2010 (EST)
27 reviewer rep
200 forum posts

DrReaper.

The best thing to do is to get the maps you're interested in and note their file sizes, ensuring that you've made any conversions that might be necessary for operation in the GPS as that can sometimes inflate the file size. Also, most maps come in segments, so they can be partially loaded by the region in which you're interested, reducing the amount of data you need the unit to hold at any one time.

6:42 p.m. on February 23, 2010 (EST)
14 reviewer rep
318 forum posts

Yock,

Yeah I am getting the 60CSx now. Thanks for your advice. I downloaded the topo maps Larry posted. I am sure I will need the extra storage. The map files are massive. If I wanted the BLM, streets and a topo map I will need to use extra memory.

10:16 p.m. on February 24, 2010 (EST)
TOP 10 REVIEWER REVIEW CORPS
2,264 reviewer rep
5,188 forum posts

In CA you cannot disturb any historical sites. I would GPS them and hand that information to the university if I found any. I think your confusing Meteorites and Historical sites. I think the meteorite hunter performs a useful service to be truthful. The meteorites will rust and be lost to everyone if they are not dug up and sold into private collections that will take care of them.

No, I am not confusing historical sites, Historical Sites (officially declared), archaeological sites, and meteorites. These all have different legal status. However, by disturbing any of these, and particularly by removing, damaging, or otherwise altering any of these, you are at the least impacting the scientific and historical value. Moving any items from any of these, regardless of the legal status, compromises the possibility of obtaining the scientific and historical information, regardless of how well-meaning the person moving the item may be. There is an ongoing huge controversy in the archaeological world, including major legal battles on this point. Private collectors just do not have the knowledge or techniques to preserve or extract the scientific information from meteorites.

10:35 p.m. on February 24, 2010 (EST)
TOP 10 REVIEWER REVIEW CORPS
2,264 reviewer rep
5,188 forum posts

Bill,

That's new information for me, thanks. How much of that can be made up by WAAS correction?

Not much. The error budget for C/A code is 7 meters multiplied by PDOP (used to be that most GPSRs provided PDOP, which is basically a geometric dilution of precision resulting from a less than ideal arrangement of the satellites in view at a given moment). This includes errors due to lack of timeliness of the ephemeris in the message (hence errors in the position of the satellites as calculated by your GPSR), clock errors (which are only partially corrected by the iterative 4-dimensional solution), and most important, atmospheric effects (mostly the ionosphere). WAAS provides corrections to the ephemeris and clock (for each satellite) and a rough correction for the atmosphere, based on a network of several dozen ground stations in US territory (that's why WAAS does not give good corrections in most of Canada or at all in other parts of the world).

WAAS cuts the probable error by between 1/3 and half, depending on a number of factors (you can't correct for really bad geometry, like having all visible satellites in nearly a straight line across the visible sky). So with good visibility of the satellites and good reception of a WAAS satellite, you can get to 3-4 meters error circle. That's 95% (2 sigma), so half the time you are within 5 or 6 feet of where the GPSR says you are.

P/Y code for authorized users gets about half the error circle, and with post-processing and other information can get to the sub-meter level.

4:20 p.m. on February 27, 2010 (EST)
14 reviewer rep
318 forum posts

What kind of information can you collect from a meteorite impact? I mean the meteorite is the thing everyone is after. That is why they put them under microscopes and try to identify everything about them. The place where it lands isn't worth anything. However if the meteorite strikes another object collectors are almost always interested in what it collided with. I would be very interested to know what scientific data could be collect from an impact site. If I am already there I may as will do all the research.

8:36 p.m. on March 10, 2010 (EST)
14 reviewer rep
318 forum posts

I picked up a Garmin eTrex Legend HCX off of craigslist today for $100 cash. It has only been turned on three times. The person that sold it to me wanted a car GPS and his parents purchased this unit. I am not sure how well it works but it did come with City Navigator 2009. The unit didn't even have its updates installed in it yet. I am pleased I could get it for so cheap and it has a memory slot. I have a 2GB memory chip for it already. It has 4 star reviews on the internet so I am pretty sure it will work for me.

April 23, 2014
Quick Reply

Please sign in to reply

 
More Topics
This forum: Older: Anyone care to share a shuttle for Art Loeb Trail? Newer: Foothills Trail
All forums: Older: Question about boots Newer: I have sinned, I'm sorry