WAAS on GPSMap 76

[Guest Chris Juricich]

So-- does it work like this? When first firing up the GPSMap 76, one needs to allow the 'almanac' to be created as it initially downloads loads of satellite info. If the WAAS is NOT enabled, does this mean that one won't get those #35 or #47 birds?

[Guest Iron Chef]

quote:

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Originally posted by Chris Juricich:

So-- does it work like this? When first firing up the GPSMap 76, one needs to allow the 'almanac' to be created as it initially downloads loads of satellite info. If the WAAS is NOT enabled, does this mean that one won't get those #35 or #47 birds?

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Correct, if WAAS is not on then it does not look for the 35 and 47 birds, but just the regular dedicated GPS birds. When it downloads the almanac though it gets info for the position of all the birdies (not that the WAAS birds move at all anyways), so no worries there if you decide to flip on WAAS to see if you can get a signal at any time. Enjoy!

 

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-Iron Chef

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agefive.com/geocache/ ~ Fe-26

Lets Drive Fast and Eat Cheese!

[Guest Kerry]

WAAS gets most if its accuracy from being able to basically interpolate atmospheric corrections much more effectively than the normal "fixed" model used in standard GPS receivers.

 

This interpolation is done within the user receivers from the IONO model downloaded from the WAAS satellites. In normal GPS almanac terms (information about the GPS satellites only) it's more of a model than an almanac but does take some time to download. A complete/full GPS almanac normally takes 12.5 minutes (minimum) to initially downlaod.

 

Also the current 2 WAAS satellites as well as being communication sats can also act as additional navigation satellites (used in the position solution) if they are flagged as available for navigational use.

 

Cheers, Kerry.

 

[This message has been edited by Kerry (edited 30 September 2001).]

[Guest Choberiba]

Don't let the fact that neither my eTrex Vista, nor your GPSMap 76 could see WAAS birds yesterday afternoon bother you.

 

First off we weren't at the altitude that pilots use. Secondly they're going to be adding birds as time goes on, giving the future a promising outlook.

 

I know it seemed high, but 1150' is barely a pimple on a ducks butt compared to real elevation.

[Guest Chris Juricich]

I hadn't enabled WAAS yesterday, Choberiba. Mainly because I forgot the manual. Alas.

 

But this morning it worked pretty well (my new GPSMAP 76, that is), bringing me within about 6 feet of FIVE BRIDGES!

[Guest Geoffrey]

WAAS is Great on my Etrex Vista out in the Boat or out in the open on land, but take it for a Run or Geocaching, and WAAS will degrade my position reading when under trees. It only works well if you have an unobstructed view of the sky, and no trees or buildings.

[Guest Choberiba]

Yeah-Yeah... Rub it in...

 

My Vista still makes better toast than your GPSMap76.

[Guest Chris Juricich]

I've come to the heartfelt (OK, I used reason) conclusion that WAAS is, currently anyway at my own lat/long (the SF Bay Area) a pretty pointless feature on my Map 76. I'd high hopes for it, but I guess we'll have to wait till more satellites dedicated to this are launched or turned to this service.

 

Now if I could only find the way to do 'averaging' on the damned thing...

[Guest gneitzke]

i was geocaching last night w/ wass on, @ all four caches i had wass reception of 47 and it was able to get my differentail position no problem, one cache was inland, and one was on the coast, no problems @ all i had wass reception the whole time, i lost it a couple times but then it was back in a couple seconds, when i was on the beach area going to 2 other caches i had wass reception @ full strength and it was foggy and everything and it was gettin sattilites great :-) so no complaints about wass here hehe by the way i have the gpsmap 76 and i live in san diego, inland was about 20 miles from the coast, and when we were on the coast we literally were on the beach lol so it worked for me

 

-- Gary

[Guest gstrong1]

Chris. On the MAP76,when you get to where you want to mark your waypoint, hit the enter button. When the screen comes up with the location info, hit the menu button, and it will let you average the location.And as far as waas goes, I don't worry too much about it,because the way I figure, of the 6,000 or whatever caches are placed around the world, more than likely a small percentage of them have posted co-ordinates that were gotten with waas enabled units. And even if they had been, the few ft. of a difference it would make, would not prevent me from finding a cache.--Gimpy--

 

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Gary "Gimpy" Strong

Rochester,NY

[Guest Chris Juricich]

You're right. If everyone's on the WAAS page, then we'll all have a much more boring pastime.

 

Then we'd just have to make it more challenging, then!