[Using benchmarks to test consumer GPS accuracy]

I've done that hundreds of times.

Usually the GPSr is a few feet off.

 

I have done that with my GPSr maybe 30 times. With WAAS on and also recieving the GLONASS satellites, I have found the standard deviation of the error distance to be around 6 feet. This would put the 90% confidence distance around 10 to 12 feet, if my memory serves me. This is near the manufacturer's stated accuracy.

[Letterbox cache near geocache]

When I plant a letterbox, I check GC to see if there is a cache nearby. If so I notify the cache owner of the situation. They are usually cooperative, and we put notes in both our clues that another non-related box is nearby, and don't confuse them.

 

I usually try to plant my letterbox 200 feet or more from a cache to avoid cross finders. Although one time a cache was planted 20 feet from my letterbox. The cacher was most cooperative, and I have invited him to events to promote caching.

 

I also check GC about once a year to see if any caches turned up near any of my letterboxes.

 

The Bird Stamper

[Letter boxers, 6 pack?]

Is this a common letterbox term? Thanks, Griz

Lettterboxers use the term "N sister tree" for a multi trunked tree. ie "four sister tree" would have four main trunks rising from the roots.

The Bird Stamper

[GPS accururacy]

The way I checked the accuracy of my GPSr is to find a benchmark with ADJUSTED coordinates. It would help if there is a clear view of the sky at the benchmark. The ones with SCALED coordinates are not useful. Then hold the GPSr over the benchmark and average the reading for 5 minutes. Do this several times a day at different hours and you will get an idea of how accurate the GPSr is.