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passdump

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    Version 2.80 software update for Legend Cx/Vista Cx/Venture Cx

    in GPS technology and devices

    Posted · Edited by passdump

    Details here: http://www8.garmin.com/support/download_details.jsp?id=1417

     

    (Despite the change history stating that this update removes lithium ion as a battery choice, its still available on my Venture Cx !)

     

    (Also, I noticed this update isn't listed on the product page https://buy.garmin.com/shop/shop.do?cID=145&pID=410 ,under the updates & download link. I got it using the webupdater program)

    Accurracy with WAAS only +- 20 feet?

    in GPS technology and devices

    Posted

     

    So if you live in the US turn WAAS on, I have never had any issues with receiving waas ......

     

     

    I agree. Also, the ' fraction of the Earth' thats covered by WAAS/EGNOS covers about 700 million people, possibly more (Europe & US). And I would imagine that's where quite a chunk of the worlds geochachers reside.

     

    If you live in Europe switch it on too. :o

    European or US Basemap

    in GPS technology and devices

    Posted · Edited by passdump

    Buy in the US if you can. The dollar rate is excellent plus products tend to be cheaper there for some reason. I got my Venture Cx there (with US base map and I am in Ireland)

     

    You can get a free official Garmin world wide base map here.( Scroll down to Garmin basemap section). I have installed it on my unit and it works great.

     

    Also if you need a microSD card get it in the US too. They're so cheap there, they're practically giving them away!

    Accurracy with WAAS only +- 20 feet?

    in GPS technology and devices

    Posted · Edited by passdump

    Does the little "D" appear on the bars of the satellite page? If the D's arent there then even though WAAS is enabled the WAAS correction data hasn't been applied/received.

     

    On my Venture CX with WAAS enabled (and with the Ds displayed), my unit regularly displays an accuracy of +-1meter (3feet)

    'Offline' Venture Cx clock isn't as accurate as I thought

    in GPS technology and devices

    Posted

    Just to clarify, once the GPSr is locked on to the satellites the display clock is dead accurate.Its perfect.

     

    The issue I wanted to highlight was that from the time the GPSr goes 'offline' the accuracy is worse than a 'cheap and nasty' quartz watch. Surprising, really, considering how inexpensive, ubiquitous and yet very accurate quartz movements are. I know the Venture Cx is a relatively inexpensive GPSr but when you look at what it does it is really quite an astonishing little modern 'miracle' -all GPSrs are. From my layman's view synchronizing with 12 satellites, piloting a fix etc. are the difficult bits that the GPSr does, I would have thought keeping accurate time would have been easy!

     

    It came to mind that just as a desktop or laptop's clock is also inaccurate (if not let synchronize through the internet) maybe the GPSr also uses a similar type of timing system (as opposed to a quartz based clock)? May be that's got something to do with it.

     

     

    Yes, the internal clocks in a reciever are inexpensive, and yet I think GPSr's are quite accurate. Understanding that one nanosecond of error equals one foot of error, GPS's would not function unless they had the near accuracy of atomic clocks. So how can they do this with cheap clocks?

     

    I agree to a point. As long as the unit is locked on to the satellites, I believe you have as near as you can get to a hand held atomic clock.However, I don't believe this is due to the accuracy of the internal GPSr clock, I think it is more to do with the fact it is 'networked' to the satellite's atomic clock, and is constantly being updated to the satelites clock. Once the GPSr is not allowed to synchronize with satellites for any length the GPSr's clock (relatively) quickly goes wrong.

    'Offline' Venture Cx clock isn't as accurate as I thought

    in GPS technology and devices

    Posted · Edited by passdump

    I noticed that when my VentureCx had not been used for a few days and I switched it on (indoors so it doesn't get a chance to 'synchronize' with any satellites) the time was wrong by 'tens' of seconds.

     

    So I did a test and I found that the GPSr was fast by 5 sec a day. I was a bit disappointed with that, as a cheap quartz watch would have much better accuracy than that.

     

    It was as I was trying to synchronize my digital camera and my GPSr clocks so that I could get very precise geotagged photos that I noticed this 'quirk'. After I had gone outside and the GPSr clock had 'synchronized' with the satellites I realized my digital cameras clock was now well out of sync with the GPSr.

     

    I am presuming (hoping!) that my GPSr isn't broken. I wonder, did anyone else notice this clock inaccuracy?

     

    Once the GPSr gets a fix on the satellites the clock does get corrected automatically.

    Accuracy Problem with Venture CX

    in GPS technology and devices

    Posted

    My friend had the same experience as jackrock yesterday. He called again and talked to a different customer support guy this time. The representative said they'd been getting calls about this, and he provided some of the same solution to him that was given in the last few posts.

     

    Well its good to know that they know.Hopefully Garmin will get their act together and release an update soon.

    Vista Cx

    in GPS technology and devices

    Posted · Edited by passdump

    I got a VentureCx a few weeks ago and upgraded to 2.70 without using it with 2.60 first. I have to say so far with regard to geocaching I have found it very good. Brings me to within 2-3 meters each time.

     

    Here is a little test I did trying to gauge the accuracy of my receiver. It basically tests the receiver against itself. There is a fixed wooden post in a field near by with a great view of the sky. I set the unit on the post and let it average a waypoint for 30mins or more each day over a week or so.

     

    What I noticed was the results varied a bit more than I thought they would have. For example (the worst deviation of one waypoint from another) one waypoint had an Estimated Accuracy (EA) of 0.7meters and another had an EA of 0.3 meters. Now if you double each EA and add the result you get

    0.7x2=1.4

    0.3x2=0.6

     

    1.4+0.6= 2 meters

     

    So the combined maximum margin of error for the EA of the two waypoints should have been in or around 2 meters. So if the EA was correct the two waypoints should have been within 2 meters of each other. Yet the two waypoints are set 11 meters apart on the GPSr screen map !

     

    I'm not sure what those results mean. Perhaps it shows varying atmospheric conditions can add quite a bit of error to a receiver's measurements.

    An interesting thing is there was minimal error north/south. The waypoints mainly differed east/west.

    Venture Cx powered by Motorola power adaptor?

    in GPS technology and devices

    Posted · Edited by passdump

    Here is some info on USB power: http://en.wikipedia.org/wiki/USB#Power

     

    For anyone who is interested these are some photos of a Garmin USB car power adaptor which came with a Nuvi 270 sat nav. The specific power details are on the label.

     

    Image:Crgr03.jpg

     

    Image:Crgr02.jpg

     

    Image:Crgr01.jpg

     

    I dont know why the images will not show. You can see them here:

     

    http://commons.wikimedia.org/wiki/Image:Crgr03.jpg

     

    http://commons.wikimedia.org/wiki/Image:Crgr02.jpg

     

    http://commons.wikimedia.org/wiki/Image:Crgr01.jpg

     

    Maybe this:

    Crgr03.jpg

     

    Doh!!! a little big. How do I resize the image?

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