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fan of analysis
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Discussion Starter · #1 ·
So, my eTrex Legend started crapping out while hunting this year. Screen would blank out at random times.

Rather than throwing the unit away, I submitted a query about repairing it with Garmin support. They wrote back to say:

The issue that you are having is directly related to changes that are being made in WAAS satellite signal. Garmin is aware of the issue and has made an update available that will resolve the freezing problem that is being exhibited on your GPS. A quick fix for this issue is to temporarily disable the WAAS reception from your system setup page. This will have a very minimal effect on your GPS accuracy.​

Thought I'd let folks know in case you haven't used yours in awhile and find it freaking out.
 

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Scavenger deluxe
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6,686 Posts
Earth’s Ionosphere drops to a new low

Watts Up With That?
Wednesday, Dec 17, 2008

The height of the ionosphere/space transition is controlled in part by the amount of extreme ultraviolet energy emitted by the Sun and a somewhat contracted ionosphere could have been expected because C/NOFS was launched during a minimum in the 11-year cycle of solar activity. However, the size of the actual contraction caught investigators by surprise. (Credit: NASA/Goddard Space Flight Center)

ScienceDaily (Dec. 16, 2008) — Observations made by NASA instruments onboard an Air Force satellite have shown that the boundary between the Earth’s upper atmosphere and space has moved to extraordinarily low altitudes. These observations were made by the Coupled Ion Neutral Dynamics Investigation (CINDI) instrument suite, which was launched aboard the U.S. Air Force’s Communication/Navigation Outage Forecast System (C/NOFS) satellite on April 16, 2008.

The CINDI suite, which was built under the direction Principal Investigator Rod Heelis of the University of Texas at Dallas, includes both ion and neutral sensors and makes measurements of the variations in neutral and ion densities and drifts.

CINDI and C/NOFS were designed to study disturbances in Earth’s ionosphere that can result in a disruption of navigation and communication signals. The ionosphere is a gaseous envelope of electrically charged particles that surrounds our planet and it is important because Radar, radio waves, and global positioning system signals can be disrupted by ionospheric disturbances.

CINDI’s first discovery was, however, that the ionosphere was not where it had been expected to be. During the first months of CINDI operations the transition between the ionosphere and space was found to be at about 260 miles (420 km) altitude during the nighttime, barely rising above 500 miles (800 km) during the day. These altitudes were extraordinarily low compared with the more typical values of 400 miles (640 km) during the nighttime and 600 miles (960 km) during the day.
 

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YourAdministrator, eh?
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Interesting information - but - I don't seem to understand what it is all about. My GPS seems to be working properly still (I use it as a speedometer), and, as far as the ionosphere goes - if it is lower than what they figure it should be, does it mean that the sky really is falling and we should be worried - or - is it something that would be a good bar conversation?
 

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I'm a map & compass guy, new to GPS,

So, what EXACTLY is 'WAAS'?
 

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Out In The Sticks
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Jeez..........I must be in the dark ages. I still use compass and maps. :eek:

I've been thinking about a GPS but I'm not familer enough with them to get one yet.
 

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Outdoorsman, Bladesmith
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105 Posts
WAAS is a method of refining the signal in order to provide a more accurate location. It is done on the device, and if you have WAAS enabled, you use that part of the signal to get your fix. If not enabled, then plain basic location is still available, but just not as spatially accurate. No big deal if you're backpacking, very big deal if you're surveying or targeting.

So if your device is acting like the OP's, just disable WAAS and take the location with a small grain of salt (10-30 meters off, maybe).
 

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Thanks Smithy! That helps!

I still carry USGS or Military maps of the area I'm going into and use compass,
BUT,
I'm learning to trust the GPS more and more as I figure out it's functions.

I've navigated everywhere from Central American jungles, to Afghanistan mountains, to Alaskan National Parks with just a map an compass,
BUT,
This GPS has features that make things SO MUCH EASIER... IF you take extra batteries!

Why didn't they put a hand crank or solar recharger on these things?

I'm digging the altitude feature.
My Kestral has air speed, pressure, density, humidity, and rough altitude built into it, but knowing your EXACT altitude is something I've never had before!

With the maps, you know within 50 feet or so (if the map is right and you are where you think you are),
With the Kestral you know within about the same 50 feet or so, depending on air density,
But with the GPS, you know EXACTLY (within 10 feet)!
 

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A compass is always good. I used to work at a camping store and during the first gulf war they shut off the GPS signals that go to the normal units that everyday people buy. We didn't sell any GPS units for a while.

They work great but there is a chance that the government can simply switch them off for a while if they feel they need to. Otherwise everybody loves GPS. Simple to use and super accurate.
 

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fan of analysis
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Discussion Starter · #9 ·
No question compass is more trustworthy than GPS... this is probably a good illustration of how GPS can fail you...

But figured many folks here might have 'em and might find the information useful for self or friends. Apparently the FCC changed the WAAS singal (don't know the details) requiring software update for WAAS to work properly.

On a related note, I'm sad to say I really need more learning & practice with a compass... but that's best saved for another thread...
 

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Most nice compasses have a mirror on them. It was always fun to see how people who had never used a compass before reacted to the mirror. A lot of the cute girls would start checking their makeup as soon as they flipped it open.

When we wanted to "break the ice" with a customer who never used a compass before we'd ask them...

Staff: "Do you know what the mirror is for?"

Customer: "No."

Staff: "So you can see who's lost."

The customers would laugh and we'd go on to explaining how it works and what the features are.
 

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WAAS is a method of refining the signal in order to provide a more accurate location. It is done on the device, and if you have WAAS enabled, you use that part of the signal to get your fix. If not enabled, then plain basic location is still available, but just not as spatially accurate. No big deal if you're backpacking, very big deal if you're surveying or targeting.

So if your device is acting like the OP's, just disable WAAS and take the location with a small grain of salt (10-30 meters off, maybe).
It's actually pretty important for those of us who use GPS hiking and on bikes if we want accurate speed. If it's off 10m behind you and then 10m in front of you the next reading, your speed will jump up and down constantly if you're moving at only 1-2mps. Not that it'll get you lost, but you might want to tear it off the bars in frustration.

@Canadian-great line! lol
 

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Thank you AgentFlounder for this information. I have an ETrex Legend but haven't used it since last year. Been meaning to get it out and charge it to take on hikes but keep forgetting. To update the software would I need to hook it up to computer or is it downloaded directly to the GPS from satellite?
 

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fan of analysis
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Discussion Starter · #13 ·
You can download the firmware updater from Garmin's website. Then you run the updater on your computer and go from there.
 
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