CharlieP
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Posts posted by CharlieP
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It's crazy to think how many people dont realize which way the sun moves.
Which way does it move?
Easy ... it moves upward in the morning, sideways in the middle of the day, and downward in the afternoon.
But getting back to the original issue ... I have a pack with everything but the kitchen sink, and also a little waist pack with just the geocaching essentials. Often when I go light, I end up wishing I had something that I left in the big pack.
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Probably the least expensive PDA that will work for geocaching is the Palm IIIxe, about $20 if you shop around. But this has 8mb of memory ... enough for geocaching ... but not the 256mb you specified. If you want 256mb, the best bet may be the Palm Zire 31 with a 256mb SD card, about $150, or less if you shop.
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Has anyone ever seen a bomb that was in an ammo can?
Yes, unfortunately ammo cans have been used for bomb containers. But how likely is it that a bomber would place a bomb beside a tree in the woods. You have to assume that the guy hates squirrels?
It is interesting that so many people assume a sinsister purpose for anything they do not easily understand. A metal box in the woods must be a bomb. A person searching for something in a park must be doing something evil.
And then there are those who can put a political spin on ANY issue or event.
Sigh.
FWIW, CharlieP
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It seems that almost all folks who cache with their kids like the McToys and some of those who don't cache with kids don't like them. I have only geocached with children a few times, but from my experience its the stuff in the cache that the kids really enjoy, especially toys. I would not normally trade for a toy since I have no use for one (my youngest "child" is now 24) but I think there should be toys in geocaches. Since this is a "philosphical" discussion, I find it interesting that there are few complaints from those who cache with kids about too many adult items in caches, even though I often find caches that have no toys in them. Perhaps parents of small children have more patience and tolerance ... from necessity.
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The electic company sure doesn't ask permission to read my meter box every month(which is next to my house, actually mounted on my house), and other utility companys...
You could deny the electric company access to the meter on your house, but you should stock up on candles and firewood first. If you are planning to watch the Super Bowl from home, I would wait until Monday to contact them.
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MY GPS76 has the ability to show tide levels at various places. I am a boater/fisherman/diver and use it to plan activities. It is also useful for planning walks on the beach.
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...and in what circumstances is it helpful?
As others have posted, projecting a waypoint may be necessary to find some geocaches where a range and bearing are used to define a position. But another useful application is for determining the position of a cache placed in a location with poor GPS reception. Lets say you are placing a cache under heavy tree cover and GPS reception is nil at the cache. Move to a nearby spot in the open and get the coords at that waypoint. Then use a compass to get the bearing to the cache and pace off the distance. By projecting the waypoint in the open to the cache location you can determine accurate coords for the cache. On my Garmin GPS76 I use the Measure Distance function to project waypoints.
FWIW, CharlieP
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I was noticing last night that they are only 1.2V, whereas a conventional alkaline battery is 1.5V.
I assume our GPSrs are not voltage-sensitive? (Mine's a Magellan SporTrak Map)
Don't worry about the voltage difference. Most devices designed for alkaline batteries will operate in a range of about 0.9 to 1.5 volts. This is because alkaline batteries drop voltage as they discharge, and go dead at about 0.9 volts. If a device would not tolerate a voltage less than 1.5 volts, it would only use a small fraction of the capacity of an alkaline cell.
But it is good to be aware that the battery level indicator on your GPS may be misleading when you use NiMH batteries. It will probably indicate about 90% when the batteries are fully charged, drop to about 50% within an hour or so, and go dead (about 16 operating hours later) when the indicator shows about 30%. Its just the difference in the discharge curve of the NiMH. Some devices allow you to adjust the indicator to recognize the NiMH difference.
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I am not sure I understand your question, but if it is "how to use a GPS to find your position on a map" I will take a shot at that. The GPS will allow you to set the map datum (WGS84, NAD27, etc.) and location format (lat/lon, UTM, MGRS, etc.) to match the map you are using. If you have the GPS set up right for the map, you just read the position and then plot it on the map.
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A small flashlight that uses 2 AA batteries. I have carried it in my pack for over 4 years now.
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In the field, one way to find the point equidistant from three given points is (1) by trial and error using the Measure Distance function on the map page of the GPS (if your GPS has this) or (2) by getting in the right general area with your GPS and moving around until the distance to each of the three points is equal. From home, you could (3) solve it graphically using either pencil and paper or (4) a map program such as Street Atlas, or (5) by trial and error using a tool such as the U.S. Coast Guard's Posaid which can give distances between points. The scientific way would be (6) by using a mathematical equation, which would probably work best with UTM coords.
Unless you are good with numbers or have a map program, methods (1) or (2) are probably your best bet.
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If you continue on the trail, hoping it will loop around and bring you close to the cache ... it won't. If you leave the trail and bushwhack a quarter mile through rough terrain to the cache, when you get there, you will see the trail 40 feet away.
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Many folks underestimate the danger associated with faulty electrical equipment. You may often hear things such as "its only 120 volts ... it can't hurt you". Wrong, 120 volts can kill you. Any device that gives even a mild electrical shock should be immediately unplugged if possible, and examined by an electrician or repairman ASAP. The shock may be mild only because there is not a good path to ground, and if a better path occurs, due to damp conditions or contact with a grounded object ... bad things happen.
Many years ago, an acquaintance was almost killed by her refrigerator. She had received mild shocks from the 'frig before and had ignored the problem. But this time she grabbed the door handle with one hand and the cold water faucet with the other ... the faucet is well grounded. Her muscles contracted from the shock and she was locked into place. She would have died except her son realized what was happening and tackled her to knock her off the circuit.
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I carry my wallet anytime I step off my own property. On my boat it is in a ziplock in the console. Life can get complicated in a large number of ways if you don't always carry a drivers license or other acceptable ID. There are more complications that arise from not carrying cash and a credit card. I know about a number of these complications because my 3 sons each had to learn the hard way that going ANYWHERE without wallet and ID will cause problems.
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I understand that gold coins resist corrosion even in salt water.
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IMHO the "off-trail hiking environmental damage issue" is sort of like my mother's warnings about crossing my eyes when I was 5 years old.
She would tell me that my eyes would lock that way, which was not true, but she was just trying to keep me from doing something that annoyed her. Purists are annoyed by the idea of folks walking off -trail, so they say it will result in awful consequences.In the forests of Northern Georgia, if a cache has not been sought for a month or so, it is often difficult to tell anyone has ever been in the area of the cache. The forest covers your tracks quickly. The "damage" caused by 100 hikers in a area pales in comparison to the effect of one large tree falling, ripping up a few hundred pounds of soil and rock, breaking other trees, and gouging the terrain on impact. And there are thousands of trees falling in our forests every year. Folks wring their hands about damage from off-trail hiking on National Forest lands which will be subject to timbering operations in future years. Need I say more.
We geocachers should obey rules set my land managers, and be careful to minimize our impact. But the managers and conservationists need to be reasonable in setting the rules.
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The most useful tool for solving many puzzles is Google. Some puzzles have hints lurking in the text, look for them. Some puzzles use standard coding schemes, which can be found with Google. Some puzzles use unique coding methods that are so obscure that unless you get lucky and "see" the solution, you can spend a huge amount of time without success. I prefer puzzles that require the solution of a stated problem, as opposed to those which require discovering a coding method.
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A geocacher here in the Atlanta area (Trez003) has used an ammo box for a submerged cache and it remained watertight at a depth of a few feet for months. He reported that the biggest problem was algae growth on the can ... it got slimy. I don't think every ammo can is that watertight, the seal has to be perfect. Another cacher used a piece of PVC with a pipe threaded plug, but that one was wet when I found it. The problem with that approach is that if you tighten the plug tight enough to seal, a wrench may be needed to remove it. Another submerged cache used a glass jar with a sealing cap (like pickles and maracino cherries come in) and weighted it so it would not float. I don't know if this proved to be watertight at depth.
FWIW, CharlieP
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Although it may not be scientific enough for your needs, I have found a few caches that required determining intersecting circles by using the map page "measure distance" function. The procedure involves determining approximately where the intersection will occur, and then placing a few waypoints near the intersection at the correct radial distance from each reference point. The intersection becomes apparent and I place a waypoint there and check the distances and adjust as necessary. It works, and can be done in the field with just the GPS.
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Thanks for those replies, I am beginning to understand this. In 1934 the station mark (EE2010) I found last week had an azimuth mark about 250 feet away, and I had assumed that was a normal distance. But in 1972 the NGS placed another station mark when they could not "occupy" the original mark because it was close to the edge of a cliff. Apparently that means they could not erect the tower described by Z15. They also could not find the old AZ mark and set a new one. I have read the description more closely, and the new AZ mark is about a half-mile away, not a few hundred feet. I see now that all references to the AZ mark are about bearings, either geodesic or grid.
So now, tell me if I understand how this works. The reference marks are to help establish the location of the station mark, and the azimuth is to set a known bearing. So if you have a point within view of two station marks, a surveyor can shoot accurate bearings to that point from each station and compute the location.
Maybe?
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I logged my first benchmark last week and I am still learning how to interpret the NGS datasheets. I don't understand the nature of the azimuth marks, what they are used for and how they are located. It seems that these marks are typically located some distance from the station mark and reference marks. What does "Grid Az" mean? Why is no distance to the azimuth mark listed in the Reference Objects table?
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With SA now turned off, does WAAS provide a SIGNIFICANT amount of additional accuracy? Also, am I mistaken in assuming the additional accuracy is only as good as the accuracy of the initial coordinates?
That depends. In an open area, like on top of a grassy hill, with good reception, WAAS may drop accuracy from 15 feet to 9 for my Garmin GPS76. But in areas with poor reception, in the woods or in a valley, WAAS may actually cause problems and reduce accuracy. Some geocachers with WAAS capable GPSR's turn off WAAS for geocaching. I turn it off if I am in a poor reception situation and the GPS seems to be having problems computing a position.
And yes, the position is only as good as the initial geocache coords, which are often in error by 20 or 30 feet and sometimes by 100 feet or more.
Do a search on this board for threads about "averaging" to learn how you can improve position accuracy.
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I am not familiar with your GPS, but I will take a shot at your questions. I was using an old marine GPS when SA was turned off and the unit somehow knew SA was off and the error/accuracy reading dropped from a typical 60 feet to 20 feet. So your error/accuracy reading probably reflects SA off conditions. But GPS makers have their own methods of computing estimated error, and therefore it is difficult to say what the number means. If you can, take the GPS to a known position that is in an open area, set the waypoint, stand at the position and see what the GPS tells you. In the open, with good reception conditions, the reported accuracy would get down below 20 feet with a typical Garmin reciever. If your GPS puts you right on the position, but reports 50 foot accuracy, then the accuracy computation is very conservative. If the GPS consistently puts you within 20 feet or so of the known position, it does not matter what the reported accuracy is, the GPS works.
You don't need WAAS for geocaching.
Other GPS units which don't automatically average, e.g. Garmins, will often display a "bouncing" position when reception is poor. The bounces may be one hundred feet or more. Out in the open with good reception the bounces are very small, like 20 feet.
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And that One nautical mile is a minute of latitude, or a minute of longitute (at the equator, but less towards the poles because of they converge.)
Or am I totally off?
No, you are close. But because the earth is not a perfect sphere, both lat and lon distance varies a little from the spheric assumption values. Try this site to see the difference.
She would tell me that my eyes would lock that way, which was not true, but she was just trying to keep me from doing something that annoyed her. Purists are annoyed by the idea of folks walking off -trail, so they say it will result in awful consequences.
Scuba Caches
in General geocaching topics
Posted
For the underwater cache I found, I anchored the boat near the cache coordinates, then took a range and bearing from the boat to the coords, went into the water and swam on the surface to the coord position, submerged and began searching. If the water was more than 15 feet deep, I would use a float to mark the zero position, or move the boat anchor to that position.