OziExplorer and handheld GPS

Submitted: Wednesday, Jul 23, 2003 at 09:48
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Am looking at buying a Garmin Etrex to run with OziexploreCE. However, according to the specs it doesn't have built in WAAS and therefore horizontal accuracy is only 15m. Is this a problem in real life or am I better off with something like the Garmin GPS72 which has WAAS built in (and a stated accuracy of 3m)? I would prefer the Etrex because it's a lot smaller, cheaper and better battery life, but not at the expense of accuracy.

All comments appreciated.
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Reply By: BurnieM - Wednesday, Jul 23, 2003 at 10:11

Wednesday, Jul 23, 2003 at 10:11
There are no ground stations supporting WAAS in the Asia/Pacific region. If you leave WAAS turned on then your accuracy will be worse than with it disabled.
WAAS article

In practise with SA turned off (has been since May 2001) you can expect 5-10 metre accuracy on a consumer grade GPSR.

Personally I believe that the GPS72/GPS76 are more robust than the Etrx series.
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Follow Up By: SimonIT - Wednesday, Jul 23, 2003 at 10:56

Wednesday, Jul 23, 2003 at 10:56
Thanks BurnieM,

Your link provided some interesting reading...especially this comment.

"So the bottom line, discount WAAS in your GPS selection process if your sole use is outside the USA. It's a feature that can't be used in Australia".
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Follow Up By: SimonIT - Wednesday, Jul 23, 2003 at 11:14

Wednesday, Jul 23, 2003 at 11:14
Another question if I may...

Have you had any experience with the Etrex/GPS72's ability to hold a signal with overhead cover etc... and their TTFF.
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Reply By: Member - Melissa - Wednesday, Jul 23, 2003 at 10:25

Wednesday, Jul 23, 2003 at 10:25
Hi Simon,

We're using the Garmin GPS12 with OziExplorer and have been very impressed with this set-up. Accuracy is spot on.

:o) MelissaPetrol 4.5L GU Patrol &
Camprite TL8 offroad camper
AnswerID: 25675

Reply By: Member - Colin (ACT region) - Wednesday, Jul 23, 2003 at 10:55

Wednesday, Jul 23, 2003 at 10:55
Why would you need a GPS with accuracy better than 3 m or even 15 m ? If you are using the GPS in conjunction with a map, the accuracy of the map is probably only 100 - 200 m ! Most of the maps are quite old and if you read the blurbs on the differences in Datums the accuracy can vary a lot. Also, depending on the map scale, take a look at the thickness of a line on the map, what distance does that represent on the ground ? and is that 'line' still in the same place (ie. roads) as the feature on the ground?

I have an Garmin Emap (very happy with its performance) and intend getting Oziexplore, Geoscience Aust 1:250 000 map CD's and probably a laptop in the near future (2nd hand laptops are available for around $700, and just load the software you need from your PC)

Remember, like a paper map the GPS is only a guide, so don't take the info 'provided' as 'gospel' !

PS. The Grey nomad thing is tempting me as well - I retired from the APS 12 months ago, and the travel urge is starting to get unbareably strong. Just need to move the son/daughter-in-law and grandchild out and talk my younger partner into retiring.
Hmmmmmmmm
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Follow Up By: Member - Bob - Wednesday, Jul 23, 2003 at 13:05

Wednesday, Jul 23, 2003 at 13:05
Colin, laptop screens can be disappointingly hard to see in a car during daylight. I did that initially, but used a 15" TFT monitor connected to a laptop on my last trip. Some monitors run on 12 volts, which would obviate the need for an inverter. I am presently trialling a system where I leave out the laptop altogether and use a discarded Celeron 333 connected to the 15" display. Runs off 400W inverter. I have a PDA and considered connecting the GPS but the screen is too small to think of using as a navigational aid in the car. (Inverter $200, display $500 = same as old laptop)
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Reply By: Member - Rohan K - Wednesday, Jul 23, 2003 at 15:10

Wednesday, Jul 23, 2003 at 15:10
Simon, we use an eTex with Ozi and a laptop. The eTrex is as accurate as any othe low to mid-priced GPS unit and can get to within 1 metre when all the conditions are right. I regularly get to 3 metre accuracy and that's more than adequate unless you're trying to use it to negotiation one of those garden-hedge mazes.

The eTrex is a great little unit but, I must admit, I prefer the buttons on the front as with my Garmin 45 and the new Garmin Geko. Its actually more fiddly trying to manouvure your fingers to press all the side buttons and they're a pain if you use one of those side-gripping cradles to mount it.

The eTrex gives pretty good reception even under cover but I have had it lose the satelites whilst in the bush in Yengo NP and just recently in the inland forests on Fraser Island. Mind you, these are pretty dense forests while almost complete canopy coverage.Smile, you're on ExplorOz
Rohan (Sydney - on the QLD side of the Harbour Bridge)
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Reply By: Member - Colin (ACT region) - Wednesday, Jul 23, 2003 at 21:48

Wednesday, Jul 23, 2003 at 21:48
Wouldn't it be great if if there was a 'mid size' screen available to connect to the GPS - about 1/2 the size of a laptop screen, about 15/20 cm. Some top spec cars have screens in the dash and even in the headrests. Would fit nicely in the centre 'glovebox' in the Forester. Why hasn't a techno whiz come up with a solution to a bigger GPS screen, or has it been done already ??????????Colin - Subaru Forester
- size isn't everything ! -
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Follow Up By: wazza - Thursday, Jul 24, 2003 at 09:41

Thursday, Jul 24, 2003 at 09:41
Col, i would like to be able to justify one of thesem but they are about $600 by the time you land one here in Oz.

http://www.xenarc.com/product/700y.html
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Follow Up By: Member - Rohan K - Friday, Aug 22, 2003 at 11:12

Friday, Aug 22, 2003 at 11:12
Colin, there is. Jayco sells one for about $400 (I think). It's a 7" or 8" (18 cm) screen.Smile, you're on ExplorOz
Rohan (Sydney - on the QLD side of the Harbour Bridge)
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Reply By: Trekker - Sunday, Aug 17, 2003 at 07:04

Sunday, Aug 17, 2003 at 07:04
Glad I found this post. I am looking at purchasing my first GPS and after all the discussions I've had I will probably purchase the GPS72. I have a laptop and I guess the next thing to do is save and purchase Oziexplorer.
AnswerID: 28153

Follow Up By: SimonIT - Tuesday, Aug 19, 2003 at 10:12

Tuesday, Aug 19, 2003 at 10:12
Hi Trekker,

I've used the Garmin GPS72 a bit and it's a great unit. In the end I went for the Etrex because it had all the functionality that I wanted (which was basic only) as I am using it in conjunction with OziCE. However, if I was going to be just using a GPS by itself I would recommend the GPS72.

Have fun.
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Reply By: Niko - Friday, Aug 22, 2003 at 00:15

Friday, Aug 22, 2003 at 00:15
All Hand Held GPS in the past 5 years will give you exactly the same accuracy no matter what brand. Wether it be the Garmin Geko101 or a top of the line Magellan or Garmin, they pretty much all have the same engine. Where the difference is notable is in the features and that is all your paying for. However, in saying that if you want better than the 5 to 10 metres I suggest you hook up a differential beacon that receives free corrections pretty much the whole of the east coast and inland some 200km or from Esperance to Geraldton and then a spot up in Port Hedland, again approximately 250km inland. This receiver will cost around $900. If you want differential further in land start looking at purchasing the GPS for approximately $12,000 and $2,500 a year for the signal. Ok, so, do you think you need better accuracy as one member said "Maps have a resolution of about 100 metres or so anyways"............ ? I don't think it's necessary.

Consider this, differential will give you 2 metres consistantly for the above prices (Can get 0.5 metre accuracy for inland differential if you want but add another $3,000 for the unit and $1,000 for the signal per annum) or is 6 metres for 95% of the time sufficient?

Oh and by the way, don't consider hooking up a differential receiver to a Magellan GPS300 or GPS310, it doesn't work. GPS315 is the minimum. All Garmins work well with Differential.

AnswerID: 28689

Reply By: Member - Glenn(VIC) - Friday, Aug 22, 2003 at 14:27

Friday, Aug 22, 2003 at 14:27
Simon,

I have a Garmin Etrex Venture connected to iPaq handheld and sometimes laptop. With the external antenna purchased from this site, I have no problems at all. Great GPS for the price and works well with moving map software. Just buy a null modem connector to connect GPS to handheld. I bought one, as well as gender benders from Dick Smiths for under $30.

Great set up, I love it.Just Do It!

AnswerID: 28738

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