Please Explain Boomerang Effect...

[+Johnson Party of 6]

I should have read though some posts before posting my first question. (See other post about Sportrek Map). I have experience what I guess was satellite lock- I was tracking great until about 10 feet from the cache and then the gps distance jumped up to 75. I did finally find the cache. But is there something you can do to "unlock" them? Outside of moving out of the trees, etc. And what is the boomerang effect?

[+tirediron]

"Boomerang effect" isn't a term I'm familiar with, however depending on the terrain, you can experience signal reflection. This is more common in urban enviroments, among tall buildings and such. It is also an effect that Magellan's with their quad-helix antenna are more susceptible too.

 

Satellite lock is actually a good thing. It indicates that that your GPSr is tracking the sattelites. If you are experiencing problems like you described, find a nice, clear area where your unit indicates it has a good signal from a minimum of three satellites (check your manual to see what this should look like) and wait for a few minutes. Allow the GPSr to "settle" and then head off to the 'cache.

 

Another technique that I have used involves triangulating. Walk towards the 'cache as long as you have a good signal, and not the distance and bearing just before it loses lock. Repeat this from several differnt directions, and (in theory) the 'cache is in the middle of that area, where lines of bearing would cross.

 

Good luck!

[+Renegade Knight]

...depending on the terrain, you can experience signal reflection. This is more common in urban enviroments, among tall buildings and such. It is also an effect that Magellan's with their quad-helix antenna are more susceptible too...

I have noticed this effect on bridges and in canyons. It's an area where the Patch antanea in the eTrex GPS's is noticibly better than the Quad Helix in the sport tracks. Noticibly is not all that much though.

 

See my post in your other thread for boomerange effect.

[+embra]

"Satellite lock" occurs when your GPSr is abale to obtain sufficient information to calculate a position...it "locks in" to its place on the earth grid. The jumping around of the apparent position of the cache as you get close in is a phenomenon that many experience, but I don't know that there's a name for it. I think it happens due to random error in position calculation; it shows up when you're close in because the error is such a large proportion of your distance to destination. When you are 500 or more feet away, the error is a very small proportion of your true distance to destination.

 

As for the "boomerang effect," I presume you are asking about what I have heard called the "slingshot effect." That seems to happen with Magellans, which appear to calculate some sort of moving average rather than an actual real-time snapshot of where you are. I don't really know the reason, but Maggies seem to lag slightly in their position readout when one is moving. The impact of that is that you can easily walk past a cache while your GPSr says you are still approaching it. Then, you discover you are on the far side of where you want to be, and have to come back like a rubber band snapping you back from the farthest point.

 

If you are experiencing something like that, you may want to hold up from a suspected cache placement when your GPSr says you are 100 or 75 feet away, let it settle down a little, and then start to move in closer slowly.

[+Tahoe Skier5000]

"Ricochet Rabbit" to add another term to the alphabet soup here.

[+Johnson Party of 6]

Thanks for the info! I was getting really confused. Can't wait to try it out again.

[+gbod]

You might also want to read this thread where the so called rubberband, boomerang, or slingshot effect was first brought up (I think) in the forums a while back.