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Re: [etrex] Re: looking for a replacement for my etrex legend

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  • Sarah Longrigg
    Many thanks for the responses. I think I would prefer the rubber band problem to the problems Jim and others describe with the etrex 20, so that narrows down
    Message 1 of 10 , May 3, 2012
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      Many thanks for the responses. I think I would prefer the rubber band problem to the problems Jim and others describe with the etrex 20, so that narrows down the field a bit for a start.

      From what you are telling me, and having looked at the reviews again, I'm now inclined to go for the Vista HCx. Hopefully the rubber band might hold out as long as it did on my previous one which I had for nearly 9 years. The rubber band got loose and made it a bit difficult to operate the buttons, but only became a real problem towards the end.

      Sarah

      [Non-text portions of this message have been removed]
    • Bill Fuhrmann
      My version of MapSource is version 6.15.11 and shows the date and time of the waypoints in the comment field. They are saved in the unit and I am surprised
      Message 2 of 10 , May 4, 2012
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        My version of MapSource is version 6.15.11 and shows the date and time of
        the waypoints in the comment field. They are saved in the unit and I am
        surprised that they are not in your legend. In the unit I can see the date
        & time by doing a find on waypoints and selecting it.

        The altimeter has two modes. Barometric with automatic calibration by the
        GPS signal and barometric that you calibrate. I would love to see them add
        the third option of GPS signal only.

        I am curious about what barometric altimeter you have used that is worse
        than the ones in a typical GPS. The altitude part of the GPS fix is
        notoriously bad. I have generally heard that it is roughly 3 times the
        position error.
        The problem is that you need to calibrate a barometric altimeter and
        Garmin's automatic calibration starts out assuming that the barometric
        pressure is the same when you turn it on as when you turned it off. It can
        take an hour to recalibrate, which it does continuously while it is running.
        If your weather is stable, calibrating it to a known altitude (like your car
        in the driveway) is very accurate and repeatable. We went hiking in the
        mountains outside of Boulder Colorado a couple years ago and one of the guys
        calibrated his at a lower altitude and then found a marker up on the trail
        and it showed a difference of 1 foot from the marker.


        --------------------------------------------------
        From: "Sarah Longrigg"

        > Two more questions -
        >
        > Does the Vista Hcx also have the normal satellite-sourced altitudes as
        > well as the barometric ones? I have found the satellite ones to be more
        > accurate.
        >
        > Also, do the waypoints automatically log the date and tie when they were
        > created?
        >
        > Thanks
        >
        > Sarah
        >
      • molongriff
        Bill Sorry not to have replied before as I was away. Many thanks for your help. I think the key here is If your weather is stable. Ours in Scotland is
        Message 3 of 10 , May 18, 2012
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          Bill

          Sorry not to have replied before as I was away. Many thanks for your help.

          I think the key here is "If your weather is stable." Ours in Scotland is anything but stable. I've found the GPS altitude to be about as accurate as you suggest, probably more accurate than that, but when I had a barometric altimeter it was nothing like as good as that. In fact I set it to alert me when I reached an altitude of 3000ft and on two separate occasions it kept going off along a ridge leading to a summit that was under 2900ft despite calibrating it first. Maybe the barometric altimeters have improved since then as that was about 10 years ago.

          So I think I'm now looking at the latest version of the Legend.

          Sarah
        • Bill Fuhrmann
          As you said, your weather is unstable and that will affect any barometric altimeter as soon as the barometric pressure changes. I would hope that Garmin would
          Message 4 of 10 , May 30, 2012
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            As you said, your weather is unstable and that will affect any barometric
            altimeter as soon as the barometric pressure changes.
            I would hope that Garmin would be updating their software to look for
            systematic differences in the two readings which would create a divergence
            of the values as the barometer changes and then adjust the calibration.

            I have not done any serious tests to verify this but did verify that the
            unit starts at the previous calibration when you turn it on and can take an
            hour to totally settle as it recalibrates from a step change in barometric
            pressure.
            The experiments were done by turning the unit on in my garage and leaving it
            sit on a shelf. There is definitely a curve shown in the altitude as it
            recalibrates to the new pressure and altitude. I have seen some changes in
            altitude when doing some trails and getting back to the start. It took
            about an hour to calibrate to the point where I couldn't eyeball a
            difference between the calibration change and the stability of the altitude
            recording.

            It would be interesting to see the altitude plots from a trail (along with
            some done at a constant altitude) that were done with non-changing vs.
            changing weather. It would probably assist if there was also a recording of
            the barometric pressure at the same time.
            My experiments were done to see how stable the position was over time and
            finding that it included an altitude shift due to recalibration was an
            interesting extra find.


            --------------------------------------------------
            From: "molongriff" <slongrigg@...>
            Sent: Friday, May 18, 2012 3:26 PM
            To: <etrex@yahoogroups.com>
            Subject: [etrex] Re: looking for a replacement for my etrex legend

            > Bill
            >
            > Sorry not to have replied before as I was away. Many thanks for your help.
            >
            > I think the key here is "If your weather is stable." Ours in Scotland is
            > anything but stable. I've found the GPS altitude to be about as accurate
            > as you suggest, probably more accurate than that, but when I had a
            > barometric altimeter it was nothing like as good as that. In fact I set it
            > to alert me when I reached an altitude of 3000ft and on two separate
            > occasions it kept going off along a ridge leading to a summit that was
            > under 2900ft despite calibrating it first. Maybe the barometric altimeters
            > have improved since then as that was about 10 years ago.
            >
            > So I think I'm now looking at the latest version of the Legend.
            >
            > Sarah
          • molongriff
            Bill Many thanks for all the comments. As you may have noticed, I sent that email 12 days before it got sent out to the group, and also my 2 latest emails were
            Message 5 of 10 , Jul 6, 2012
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              Bill

              Many thanks for all the comments. As you may have noticed, I sent that email 12 days before it got sent out to the group, and also my 2 latest emails were reversed in order so they didn't make sense. After about a week I gave up waiting as I really needed a GPS quite urgently by then, so I went ahead and ordered the Legend HCx. It was the cheapest, and I had been perfectly satisfied with my previous Legend except that faster and more accurate models weren't available then so that is a bonus. From what you said, I really didn't like the idea of the barometric altimeter with our very unstable and constantly changing weather conditions and certainly didn't want to pay more for it.

              As I got a really good deal, I took a step I don't usually think is worthwhile and took out a highly rated 3-year warranty on it which can also be cancelled at any time for a proportional refund if I change my mind. As this includes accidental damage, it will also cover all the possible hazards such as dropping it in water (I found my previous one wasn't as waterproof as they said), getting it run over by a car etc as well as the dreaded rubber band problem. Talking of getting it run over by a car, I heard of someone who had this happen to their GPS and it survived it undamaged, which made me wonder all the more what on earth our postal delivery system did to my first one which arrived with a smashed screen.

              Sarah

              PS I posted the above to the group on 31st May & 16th June but it never made it to the group. It's now 7th July and I have been mostly happy with the way the GPS is working. I checked it on a couple of summits of known height. Here in Scotland the weather is very unstable, which is probably the biggest reason why I got very poor results with a barometric altimeter. I would say that the elevation readings I got, even with the old GPS, were very much more accurate - usually within about 10m - while the barometric altimeter I had set to sound an alarm at 914m (3000ft) was constantly going off along a ridge on which the highest point was 879m and I was nowhere near that height when it started beeping. I went up this same hill with the new etrex Legend HCx and got readings of 877m & 874m at the summit. On another hill with tops of 358m & 361m I got readings of 356m & 357m for the first top and 359m & 363m for the second top, though I should probably deduct 1m from most of these, as I was holding the GPS at waist height.

              The altitude was also within about 10m inside our house, where I wouldn't have managed to get a signal before.
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