julianh

Yes. They sugggested I perform a hard reset. A hard reset is exactly what I would do in this case. If you have a data cable: - Download EasyGPS and backup all your waypoints, routes and tracks. - perform the hard reset. - let the webupdater run and unstall the firmware. Even reinstall die current firmware. Reinstalling the same firmware once helped with my GPSMap 60CSx after it had issues with the compass. - Send the waypoints, tracks and routes back to the Geko using EasyGPS - Let the Geko sit with good skyview for 20 minutes or so in order to download the current almanac GermanSailor If this is the same probelm as with the old B&W Vista, a full re-set would provide only a temporary fix. Sooner or later, the clock would get scrambled again (sometimes even in the model of a single track-log, with the unit on the whole time, with a good satellite fix throughout). This was very frustrating for me, because: 1) Garmin MapSource would not load the track logs, because it recognised that they were corrupted; 2) If I loaded the track logs with a 3rd party application, I could view them, but could not use them for geo-tagging my digital photos (because the time/date stamps were wrong). Garmin told me they were aware of the problem, but they could not offer a permanent fix, other than to upgrade to a newer model (Summit HC in my case).

My altimeter always seems to read about 2,000 metres (6,500 feet) in commercial planes. According to Wikipedia http://en.wikipedia.org/wiki/Cabin_pressurization : "The outflow valve is constantly being positioned to maintain cabin pressure as close to sea level as practical, without exceeding a cabin-to-outside pressure differential of 8.60 psi. At a cruising altitude of 39,000 feet (FL 390), a Boeing 767's cabin will be pressurized to an altitude of 6,900 feet."

I agree 100% - while I am a big fan of the built-in electronic compass (to get good bearings while stationary, "Sight'n'Go", etc), whenever you are navigating out in the boondocks, you should probably be carrying: GPSr Spare batteries Paper map(s) Compass Water Food Appropriate clothing 2-way Radio EPIRB etc, etc, etc (However, when navigating in well-populated near-urban environments, I find my Summit HC and mobile phone are generally all I really need! )

Summit HC has it

That probably would only apply if the instrument taking the reading is directly subjected to the air moving at high speed, i.e. outside the aircraft. If the GPSr is inside the aircraft then there is no high airspeed around the instrument, and therefore no Bernoulli effect. In my experience (in cars), most modern cars seem to be set up such that they have dominant ventilation outlets in an area of low external pressure (e.g. near the C-Pillar) so as to ensure strong ventilation by suction, even if the AC and fan are turned off, all windows closed, etc. The air pressure felt inside the cabin will be dominated by the external air pressure at the dominant air inlet and / or outlet. In my observations, this means the altimeter typically reads about 5 to 10 metres high when travelling at around 100 km/hour. The altimeter reading will instantaneously drop by about 5 or 10 metres when you stop. Opening and closing windows and air vents can change the indicated elevation when travelling at speed, because it can change the dominant ventilation points to an area of higher or lower air pressure. I would expect to see a similar behaviour in an unpressurised aircraft, but I don't have any first-hand experience.

The following works with a Garmin - a similar procedure should be possible with most brands. Firstly - if your GPSr has a barometric altimeter, and the plane is pressurised, you will want to set it to "Fixed Elevation" mode and "Auto-Calibration Off" - otherwise, your altimeter will record your elevation as being the equivalent elevation of the cabin pressure (maybe 2,000 metres maximum or so), so you will lose most of the 3D content. If you are in a non-pressurised aircraft, calibrate your altimeter before you start, and have the barometric altimeter set to "Variable Elevation" with "Auto-Calibration On". Note that there will still be elevation errors due to the Bernoulli Effect (higher air-speed gives lower air pressure) - I can't tell you what impact this will have for elevation records in your aircraft - it will depend on aircraft type, flying speed, etc. You will need to experiment to find out. Set the track-log to record at suitable intervals - I find "Method: Auto" and "Interval: Normal" works well for me. Have your GPSr set up where it will get the best possible satellite signal - on the dash under the windscreen would be a good choice. Record a track-log throughout your flight. Transfer the track log into MapSource, and then select "View | View in Google Earth". Set Google Earth to show vertical exaggeration = 1.0. You should now be able to see your track-log overlaid in 3D on the normal Google Earth imagery. Hope this helps!

Gee ... how hard can it be to be to fix the code to draw a map for >S60, when you have already fixed the issue for >N60?! I wonder if this is related to the issue of huge distortions that you get in MapSource 6.15 at high latitudes? (e.g. Are they using the same projection algorithms in the Colorado / Oregon / Dakota series?) I tried loading the Antarctica map into MapSource and then onto my Summit HC. The Summit pans and zooms just fine on this map, and the map is properly scaled, but in MapSource, it is stretched an enormous amount E-W, as you can see if you create a waypoint with a proximity circle - it displays as an ellipse with an aspect ratio of about 2:1 at S65, increasing to about 5:1 at S80!

Yeah - it's a mystery to me how a GPSr can get it's date wrong (by several decades!), but can still find the satellites AND get your position correct! Nevertheless, this is a known bug with the old B&W Vista model, and it looks like it could be an issue with the Geko range too. (If you do a Google search for "gps shows incorrect date" you will find a number of links to forums etc where users have requested a fix to this problem on various models, and as far as I know, there is no permanent fix available.)

Here's the short version! Set your track log to record your position at regular time intervals - say every 10 minutes - then set your GPSr in a fixed location for 12 hours or more. You can then see how much the recorded position moves around as the satellite positions change.

Yeah - if you read my linked thread, you will see I contacted Garmin (via the local Australian agent) - they told me they were aware of the issue with the B&W Vista, but there was no permanent fix available!

Simple test for anyone who wants to find out just how consistent their GPSr is: Ideally, first download the Trimble Planning Tool, and notice how the number of satellites and DOP will vary over time at your location. Go to a known fixed location - preferably a benchmark with known accurate coordinates, but your mailbox will do. Wait a couple of minutes for your GPSr to "settle" (yes, it does matter!), and record the coordinates. Use a coordinate format which allows the highest inferred precision - UTM is good, because it will report your location to 1-metre precision in both E-W and N-S directions. Also, make a note of the EPE and number of visible satellites as reported by the unit, and make a note of the number of satellites and DOP as reported by Trimble Planning Tool. Go back and repeat a few hours later the same day - try to choose a time when the Trimble Planning Tool reports a significantly different number of satellites and DOP to your first visit. Repeat again later the same day. Repeat the above series of tests the next day ... and the next .. and the next. (Note - if you check the Trimble Planning Tool, you will see there is general tendency for the number of satellites and DOP to be more or less repeated on a 24-hour cycle. For the most meaningful results, you should NOT repeat the exercise on a rigid 24-hour cycle. 9:00 a.m. on 11 January is going to be ROUGHLY the same as 9:00 a.m. on 12 January is going to be ROUGHLY the same as 9:00 a.m. on 13 January ... but 9:00 a.m. 11 January is probably going to be quite different to 3:00 p.m. 11 January.) And now here is the clincher - to qualify as a meaningful scientific experiment, there has to be a prediction: All of your position records taken at times of day when Trimble Planning Tool shows a low DOP are likely to be quite tightly clustered around a common location (the centroid of which SHOULD correspond to the true location) - say plus or minus 3 metres in any direction if you have a modern high-sensitivity GPSr, good sky visibility and limited multi-path at your location AND the reported EPE at these times will probably be quite low (perhaps 3- 4 metres?) Your position records which are taken when Trimble Planning Tool predicts a high DOP are likely to be scattered over a larger distance (although note that some will probably still be "spot on"!) AND the reported EPE will probably be higher. When someone completes this exercise and can show that their unit consistently gives a fix within 2 metres of a single location at all times of day or night, I will be truly impressed! (Because it can't happen, according to theory which underpins the whole GPS system!) (P.S. Of course, the easy way to collect data is to set your track log to record your position at regular time intervals - say every 10 minutes - then set your GPSr in a fixed location for 12 hours or more. You can then download the track log and see how much the recorded position moves around as the satellite positions change.)

Hmmm ... I wonder if this is the same basic problem as I encountered with my B&W Vista back in 2007/08 - read about my experiences here: http://forums.Groundspeak.com/GC/index.php...=177915&hl= The unit worked fine apart from the time / date problem. However, this meant my track-logs were all corrupted (invalid time and date), so I couldn't use the unit for geo-tagging photos, etc. Coggins pointed me to a link http://www.gpsinformation.org/dale/secret.htm for the undocumented "super-master-reset", which would provide a temporary fix, but the time and date would inevitably get scrambled again from time to time. In the end, after getting the same problem on two separate units (and hearing about other Vista owners who had the same problem), I ended up swapping the unit for a Summit HC, and haven't looked back since! Hope this helps!

Check out this thread for some real-world tests: http://forums.Groundspeak.com/GC/index.php...&hl=battery My own results (with a Summit HC) showed: Batteries: Bank of new alkalines - measured at 2.96 V for the test WAAS: Turned off (no WAAS in Australia) Compass: Turned on and off, held steady, moved around, turned around, etc - no discernible difference to current demand No back-light: 65 to 70 mA (190 - 205 mW) 50% back-light: 100 to 105 mA (300 - 310 MW) 100% back-light: 150 to 155 mA (440 - 460 mW) (Subsequent testing with WAAS on and off showed no discernible difference in current drain, as also indicated in tomc61's tests on a Vista HCx.) Back-light usage certainly affects battery life; compass, altimeter and WAAS have no discernible effect. Your mileage may vary!

Hmmm - that's not my experience with a Summit HC - although the detailed algorithms with an Oregon 300 are probably different. Firstly - I assume you performed an initial manual calibration before starting to record total ascent & descent, and you have "auto-calibrate" turned on? This is necessary to let the GPSr "do its magic" to adjust for varying barometric pressure over time. If so, have you repeated your experiment with the GPSr outside where it can get a good satellite signal? Inside, you will be getting a significantly degraded signal, which will significantly affect your position accuracy, and can very significantly affect your GPS elevation accuracy. When you are indoors, you may be seeing satellites in only a relatively small patch of sky; this may be able to give you a reasonable 2D fix, but it is likely to give a very poor elevation fix. That is, when you get a poor quality signal, your GPSr will deduce that it is wandering around (when it is actually stationary). The amount that it thinks it is wandering vertically is probably twice as much (or worse) than the amount of horizontal wandering. This will be reported as an accumulation in the track log AND accumulated ascent and descent. (Auto-calibration will tend to "damp out" the vertical wandering, but it will still think it is rising and falling from time to time as it adjusts the real-time barometric pressure estimate.) If you are outdoors with a reasonable 3D satellite fix, the amount of horizontal and vertical wandering will be MUCH less, and this will translate to MUCH smaller accumulated movements in the track log and total ascent / descent. I have just run a stationary test with a reasonable (but by no means perfect) sky view - after 45 minutes, it is showing total ascent = 1 metre; total descent = 1 metre. Not too bad! Hope this helps!

When did the degree become a unit of measuring time? (And is that Celsius or kelvin?)

2 days 3 hours 37 minutes 14.356 seconds

Your GPSr contains a computer chip - don't ask me what chip, what programming language, what operating system, etc, as it will vary for each make and model, but regardless of that, there is a computer at the heart of your GPSr. I will bet that the internal maths is done in floating point maths, possibly using Single Precision (32 bits - about 7 decimal places equivalent precision – unlikely,) but more likely Double Precision (64 bits - about 14 decimal places equivalent precision). (It's even possible that the maths is done in Quadruple Precision - 128 bits, or about 28 decimal places - but that would sound like overkill to me for a consumer device.) I will also bet that the fundamental geometry maths is done internally using radians as the angle of measure (one radian is approximately 57.3 degrees), not degrees, degrees and decimal minutes, degrees minutes and seconds, mils, grads, UTM, or whatever. This is because all the standard computer trigonometric functions are based on algorithms which use radians as the unit of measure, and these angles can then be converted into other customary units of measure. The GPSr's processor will just blindly go on doing its trigonometric maths, second after second, calculating your latitude and longitude (in radians) to the best precision that it has been built and coded to be able to determine. (There is no point in reducing the computed precision of the location internally; the rounding-off will be done on the displayed result, not the internal representation of your location.) It will then output and display this location in whatever coordinate system the user requests, and using however many places of precision the device's programmers have deemed appropriate. You can see this effect in the spreadsheet of your choice. Calculate the square root of two in an empty cell. Depending on your default settings, you will probably see something like "1.414214". Now increase the precision to the maximum available, and you should see something like "1.414213562373100000000000000000". This shows me that my copy of Excel is using Double Precision maths (14 decimal places). Changing the display format does NOT change the value stored in memory, only the way it is displayed. For example, assuming your device uses Double Precision maths, the internal maths can probably calculate a theoretical latitude and longitude to an accuracy of something like 10^-13 radians, which is equivalent to something like one micron (one millionth of a metre) at any instant; however, the device can also compute an estimated accuracy, which will be in the order of a few metres at best, so there is simply no point in displaying your location to a precision of greater than the nearest metre or foot. (Even this level of reported location accuracy is optimistic.) For consumer GPSrs with ~3 metre maximum accuracy, the maximum meaningful displayed precision in various coordinate systems is something like: 1 metre 1 foot 0.1 second 0.001 minute 0.00001 degree Any more displayed digits than this is simply meaningless. Hope this helps.

And how accurate is this conversion ? Because for survey, are you still using the antique inch or the less antique one defined as 25.4mm exactly ? Yes, if we're going to get down to sub-inch accuracy, perhaps we need our GPSrs to display in base units smaller than the inch - how about distance to destination in "barleycorns"? After 1066, 1 inch was equal to 3 barleycorn, which continued to be its legal definition for several centuries, with the barleycorn being the base unit. http://en.wikipedia.org/wiki/Inch (Personally, I'll stick with the metric system - we already have millimetres, and we can go down to microns or nanometres when the precision of these things gets significantly better! )

I assume you are referring to the fact that on models without a compass (or of you turn the compass off, or don't use it correctly), when you are stationary or moving very slowly, the bearing pointer to your destination on the "compass" screen can point in any direction whatsoever. You have to be moving to get the bearing pointer to settle down to show the way. For what it's worth - the OP has a 60 CSx, which has the built-in compass. In this case, as long as you: 1. Calibrate the compass whenever you change batteries (takes me about 20 seconds on my Summit HC) 2. Turn the compass on (I have mine on all the time) 3. Hold the unit level when using the compass screen (just like a conventional liquid-filled compass) then the unit always points to your destination, whether stationary or moving. Yes, you can in theory navigate to our destination using UTM coordinates for current location and destination, mentally subtracting the eastings and northings to get your delta east and delta north, use a compass to orient yourself (!) and then walk while watching the coordinates and updating the mental arithmetic until you are at your goal .... But for my money, I find that using the compass screen with compass turned on to show the direction, and one of the fields reading distance to destination, is far and away the easiest way to home in on my target. Hope this helps!

If you are on a really tight budget, or you are SURE you won't ever want maps, and you won't ever want to download / upload data to and from your computer, then the eTrex H is a fine unit to get started, or as a reserve unit. There is absolutely nothing "wrong" with the eTrex , apart from its limited feature set - its navigation accuracy and sensitivity is basically the same as the top-of-the-range consumer models. However, it uses a proprietary data cable (which is NOT a standard USB cable, and it is not included in the base package), so as soon as you think about uploading / downloading tracks and waypoints to / from your computer etc, you need to factor in the extra cost of the cable and USB/Serial adapter as others have noted. If you think you might be interested in loading maps, uploading / downloading tracks and waypoints, etc, I would strongly suggest you think about spending a bit more to get one of the more feature-rich eTrex units, or another model in the Garmin range. In general, the more you spend, the more features you will get. As a start, I would suggest the Legend H (B&W) or Venture HC (colour) would be two models to look at that shouldn't cost much more than the eTrex H, but add mapping capability and USB connection. Basic mapping capability (with at least 24 MB of built-in memory) is probably the first feature you will want to look for (don't forget the cost of the maps as well, although there is a pretty good range of free maps available for Garmins); colour screen is a huge advantage for mapping units (grey scale mapping is OK, but colour mapping is SOOOO much better!); expandable SD memory card, auto-routing, altimeter and compass, touch-screen, etc, etc, etc are other features to consider. Hope this helps!

As someone else has mentioned, the 4-pin connection is a far better choice than the rather fragile USB connection. It's physically more robust, and can accept a wide voltage range. Fair comment - I had forgotten that some Garmin models have multiple ports on the back. Most of the newer form-factor models (e.g. eTrex, Dakota, Oregon, etc) only have USB, and you should only pump 5V through the USB port, as far as I know.

Rather than hacking about with the inside of your GPSr, it might be safer and easier to just build yourself a battery pack that puts out ~5V DC, and wire up a short cable which feeds in via the USB connection. Keep the battery pack in your jacket if necessary for extended battery life in cold weather. Or even easier - why not just go to your friendly neighbourhood electronics store, and buy a Lithium USB battery pack; e.g. http://www.bixnet.com/5v7libapa.html Hope this helps!

My $0.02 worth ... I realise this forum is hosted primarily for geocaching purposes, but don't forget that geocaching is not the ONLY reason people buy GPSrs. For me, geocaching is an occasional diversion, not my main use. I currently have a Summit HC (which has the compass and barometric altimeter), which serves me fine - I don't need auto-routing (I use a car sat-nav for that), but I must admit I would like removable memory card feature so I could pre-load more maps for each trip, but that is another issue. The reason I will never buy a GPSr without a compass is because I use it for navigating in some pretty rugged country. Some of the places I go (deep rain-forest for example), there are no reliable permanent tracks, you can't see your destination (except every once in a while when you get to a ridge or clearing), and you can't move quickly enough to get a reliable bearing using the GPS pseudo-compass. I really find the compass and altimeter calibration "issue" is not a problem at all, and all I have to do is stand still and hold the GPSr horizontal, and Voilà! I know which way I need to keep moving to make real progress to my destination. I find the compass is reliable to at least 5 degrees in even the most challenging conditions, and I can get repeatability of 1 or 2 degrees if / when I need to shoot a more accurate bearing. Yes, I can also do the same thing using paper map and conventional compass (and I do carry both when I am off the beaten track - maps and compasses still work when your last pair of batteries go flat!), but it is truly simpler and quicker for me than conventional map-and-compass navigation. In short, if you are only going to use your GPSr for car navigation and / or geocaching in fairly open terrain, you may never see the value of the built-in compass. If (like me) you plan to use it for general navigation in some more serious terrain, I think it is well worth the modest extra expense. (For me, the compass and altimeter are far more valuable than auto-routing and 2 GB plus of memory so I could load detailed topo maps of the whole of the continent in one go. )

If they would only tell us what glue they use, at least we would know to not use it, because it doesn't work!

Not really a practical solution for a consumer device which is designed and sold as being suitable for rugged outdoors use. I really think Garmin should have designed this defect out many years ago, but I think we are just stuck with it, sadly. Garmin don't seem to care.