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Waas


dantonac
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So I had this ancient Magellan GPS 315 which predates mapping GPSes and WAAS. It did the job and will forever hold a place in my heart.

 

I kept wanting to get a newer unit, but everything I read said the WAAS sats were only 2 in number, one on each of the east/west coasts available only in the US or north America and even then only if one was in a wide open area with a clear view of the horizon.

 

So I held off upgrading the trusty 315.

 

Recently I made the plunge to a Magellan Meridian color with all the goodies.

 

I go out into my front yard (facing north with the house blocking the south) and I don't get a WAAS lock. My accuracy is no better than the 315 to my disappointment.

 

I go into the south facing backyard and I can "see" 2 WAAS sats and get a lock on one. My accuracy is in the 5-10ft range and I am excited.

 

So I go hunt a couple caches. One is on a beach near Lake Michigan and the other in a forrest under heavy tree cover. In both cases I "saw" 2 WAAS sats and locked onto one (always the more overhead one, not the one along the horizon) making the find fairly easy.

 

There must now be more than 2 WAAS sats.

 

What I want to know is where do you live and how reliably do you get WAAS corrections?

 

I drive 55 miles to work and it appears that even in my car I maintain a WAAS lock the whole way. This simply rocks.

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WAAS is pretty spotty here in BC. In Alberta/Saskatchewan, in my experience it was much better? Although last week at a cache near an international airport nearby, I could have sworn I had lock on WAAS sats. I dunno :lol:

 

edited: I stand corrected on the number of WAAS sats.

Edited by DocMagoo
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Heres the science.

 

WAAS = Wide area augmentation system. It consists of about 2 dozen ground stations and 2 sattelites, one offset from each coast of N America.

 

The ground stations gather data and transmit it to the sattelites, which compile the data and transmit the results (basically an error correction) to your waas enabled receiver.

 

The data consists of corrections due to atmospheric and ionospheric conditions (among other things). The most you'll ever see is 2 waas sats, thats all there are. The waas sats are always positioned in the same place (Geosynchronous Orbit) , they don't circle the planet like the rest do.

 

Some caveats.

 

If you already have optimum atmospheric conditions and a decent sattelite constellation overhead, you won't see much improvement using waas...because the error is small. Meaning, if you're at high altitude (as in the Rockies) on a clear day, there is less atmospheric degradation of the signal, giving you pretty good accuracy without waas. This explains why a few folks just don't see a dramatic improvement.

 

The best thing about waas is pinpointing your position when you're not moving. After you place your cache, set your receiver down and let it average for a minute or 2. Since you are not moving, and the ground stations are not moving, and the waas sats are stationary, the constant stream of error correction gives you the most accurate coords you can get. That is something that the finders will truly appreciate.

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So... is buying a GPSr that is WAAS enabled really worth it? I keep seeing people say they turn their WAAS off... I have been usisng a $99 Garmin eTrex and have found almost every cache with little difficulty, although I usually resort to the hint. I have never zeroed out over a cache...

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So... is buying a GPSr that is WAAS enabled really worth it? I keep seeing people say they turn their WAAS off... I have been usisng a $99 Garmin eTrex and have found almost every cache with little difficulty, although I usually resort to the hint. I have never zeroed out over a cache...

I wouldn't buy any GPS solely on its ability to receive WAAS signals. Mapping and other creature comforts rate FAR higher on my own personal 'importance' scale.

 

Just my incredibly humble opinion. :lol:

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WAAS is pretty spotty here in BC. In Alberta/Saskatchewan, in my experience it was much better? Although last week at a cache near an international airport nearby, I could have sworn I had lock on 3-4 WAAS sats. I dunno <_<

 

Thank You DocMagoo... I was wondering why I could not get the waas signal, even when I was on the water (in B.C.) so what I've read is true then, we are in an area that is just too far away to get the waas signal consistantly. :lol:

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WAAS is pretty spotty here in BC.  In Alberta/Saskatchewan, in my experience it was much better?  Although last week at a cache near an international airport nearby, I could have sworn I had lock on 3-4 WAAS sats.  I dunno  <_<

 

Thank You DocMagoo... I was wondering why I could not get the waas signal, even when I was on the water (in B.C.) so what I've read is true then, we are in an area that is just too far away to get the waas signal consistantly. :lol:

There are only 2 WAAS sats, and they correct all the other sats. You will see a "d" or "w" over the correccted sat bars.

 

Here is the correction area: http://www.nstb.tc.faa.gov/vpl.html

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I live in northern Utah and only once have I managed to get a WAAS lock, and it hasn't happened since. I don't fret about it though. If I got a WAAS lock, fine. If not, that's fine too. So long as I can get normal satellites to lock I'm happy.

Edited by Black Mage
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here in ontario i have only got wass once so i keep it off

 

 

I have a different question about WAAS.

I heard it drains your batteries quicker if enabled.  My question is if I have WAAS enabled, but it isn't picking up any of the WAAS satellites will it's use still drain the batteries quicker?

 

 

 

and to answer the last qestion i believe it does. your unit is always trying to lock on to those extra sats so it has to use more power to do. i could be worng but i think thats the case.

Edited by Rogue_Monkey & Minkie
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WAAS is pretty spotty here in BC.  In Alberta/Saskatchewan, in my experience it was much better?  Although last week at a cache near an international airport nearby, I could have sworn I had lock on 3-4 WAAS sats.  I dunno  :lol:

 

Thank You DocMagoo... I was wondering why I could not get the waas signal, even when I was on the water (in B.C.) so what I've read is true then, we are in an area that is just too far away to get the waas signal consistantly. <_<

I mentioned this in another thread, but I thought it might bear repeating here: BC has decent WAAS reception provided you have a reasonably clear view of the horizon. See this link:

 

http://www.nstb.tc.faa.gov/vpl.html

 

In Seattle, we can pick up the Pacific and Atlantic satellites, but both are low on the horizon. As a result, WAAS reception is generally only available when in an open area like a park, field, or on the highway. Still, that can come in handy on certain evil micros provided the hider used WAAS to place the cache.

 

If you are not receiving WAAS even when out on the ocean, then you likely have not gone throught he process of getting WAAS set up on your receiver. See this link for more information on that.

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What I don't see mentioned is WAAS certainly can't help if the placer didn't have it or average their coords when hiding.

 

This was a criteria in my not keeping the Magellan unit I won (aside from not connecting to my Amiga or Palm). I've found every cache I've hunted w/my simple eTrex and usually don't need the hints (less than half).

 

OTOH, I've had compliments on my provided coords because I average readings over multiple days...

 

Lastly, my night-caching buddy has a Gecko. Who finds it first breaks down 50/50%...

 

hth,

 

Randy

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Meaning, if you're at high altitude (as in the Rockies) on a clear day, there is less atmospheric degradation of the signal, giving you pretty good accuracy without waas. This explains why a few folks just don't see a dramatic improvement.

Is wrong.

 

Mainly WAAS corrections from ionosphere and ephemeris. Troposphere corrections not are large. Rocky mountains very much not ionosphere, so WAAS help there just like sea level.

 

WAAS help most in solar storm.

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Why would WAAS use more batteries? The reciever is always tracking sats anyway.

 

And why on earth would anyone turn the feature off? WAAS can only improve accuracy, not degrade it.

 

I have always heard there were only 2 sats with more planned for some unspecified date in the future, but the wierd thing is that both WAAS sats my gps sees are in the east. One near the horizon and the other higher in the sky. Given that I am in Wisconsin which is just east of central US that seems strange if there are still only 2 sats, one on the east coast and 1 on the west.

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With a Magellan gold gpsr, how do you know if you have a lock on the waas sats? Do they designate diff on your sat screen?

 

Cachdasher

On the screen where it tells you your position is averaging it will say WAAS average if locked. On the sat screen a WAAS sat shows up as a red W and it gets a red box around it if the GPSR is locked on it.

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With a Magellan gold gpsr, how do you know if you have a lock on the waas sats? Do they designate diff on your sat screen?

 

I believe the MeriGold is very similar to my SporTrak. On my SporTrak the 2 WAAS birds are shown with a (W) designation and are highlighted when being used. Also, on the coordinate screen you should see a WAAS designation.

 

Please bear in mind that I am a SporTrak owner and don't have a MeriGold to confirm this, but I believe the units are quite similar.

 

FWIW, here in Central Alabama I can receive a WAAS signal 99% of the time.

Edited by jeff35080
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