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Everything posted by CharlieP

  1. Yes, I use averaging. Although the averaging feature on a GPS will generally improve position accuracy, it can still yield poor results when done for a short period of time when satellite geometry is not good. I prefer to take a number of positions at times when the EPE (accuracy) display is at a low number, 18 feet or less. I then average these positions on the map page by placing the final position at a central spot in the points. This works even better if you can go through the process at some intervals of more than 30 minutes, i.e., take a few points now, then take a few points an hour later. If the points are spread way out on the map page, this tells me I may need to take more points. If they make a tight group, I get more confidence in the readings. If the cache is in a bad spot for reception, like under heavy vegetation, I go to a clearer spot near the cache, do the averaging there, and then project the position to the cache. Using these methods it is often possible to get a position that is true within 10 feet or less.
  2. Using a flashlight to discharge batteries may damage the cells, because one cell will go flat first, and then the other cell will push reverse current through the dead cell which can ruin it. If you use fully charged NiMH cells in a GPS unit until the unit shuts off from low voltage, the cells will be fully discharged for practical purposes.
  3. Some caches are meant to be tough to find, and a hint may not be appropriate. But in some cases a hint is a really good idea, e.g., if the cache must be well hidden to keep muggles from finding it, a hint may allow geocachers to find it without destroying the area around the cache and alerting muggles.
  4. Some Garmin GPS units have a Measure Distance function on the map page ... works great for determining distances and bearings.
  5. This is the grand-daddy of all ammo cans, about 3 feet long. 33 1/3 Cache in Georgia
  6. With my Garmin GPS76, either the waypoint projection feature or the Measure Distance function on the map page can be used for bearing and distance problems. When I need better than .01 mile precision, I set the Units to metric and use the measure distance function, which measures distances less than 1000 meters in 0.1 meters. I use a conversion program on my PDA to do the necessary math.
  7. Some cells tend to get very hot at high charge rates. If the cell is not designed to handle this, bad things can happen. Look at the specs for the 2500 mah cells and see if they give a max recommended charge rate. I like the slow rate chargers ... they take longer but are much easier on the cells ... sometimes slower is better. I am using some NiMH cells now that are over 4 years old and still going strong. BTW, if you have cells that seem to lose capacity after being used for a period of time only in a digital camera ... put them through a full discharge cycle or two and see if they perk up. A digital camera may only use the top 1/3 of the NiMH capacity and if the cells are not discharged more deeply they will lose capacity. A GPS unit will discharge the cells completely, so I rotate cells between the camera and GPS.
  8. Generally, standard NiMH chargers (which charge AA cells in 4 to 20 hours) can be used with different brand and capacity AA batteries. You may need to adjust the charge time for the cell capacity, e.g. a slow charger that charges 1800 mah cells in 14 hours may need 20 hours to charge 2500 mah cells. Some NiMH batteries are sold with specific chargers that charge the batteries at very high charge rates, e.g., 15 to 30 minutes. I would not recommend using these chargers with cells that are not specifically rated for such a charger. FWIW, CharlieP
  9. COST If you use your GPS a lot (e.g., 10 hours or more of operation per week), using NiMH batteries is much more cost efficient than using alkalines. You could save several hundred dollars over a period of 4 years using the NiMH. CAPACITY The newer AA NiMH cells, with capacities of 2300 mah or more, have about the same capacity per charge as an alkaline cell. DRAWBACKS The biggest drawback of the NiMH is that they will lose charge when not in use, which means that if you charge the batteries and leave them in the GPS for a few weeks, you will only have about half the full capacity left. This is not a problem if you use your GPS often. NuMH batteries may NOT be a good idea for folks who do not like to think ahead. Always carry spare batteries. VOLTAGE Although new alkaline batteries have a voltage of 1.5 volts, in operation the battery voltage drops as the battery is discharged, and the battery goes dead at about 0.9 volts. Almost all devices designed to use alkaline batteries will operate effectively at voltages of about 1.0 to 1.5 volts per cell. If the device would not tolerate a voltage lower than 1.5 volts per cell, it could only use a tiny fraction of the capacity of an alkaline cell. NiMH batteries operate in the range of 1.3 to 1.1 volts, and therefore will power most devices designed for alkaline batteries. BATTERY INDICATOR Because NiMH cells have a flatter discharge curve than alkalines, a battery level indicator designed for alkaline cells will be misleading. It will indicate that a freshly charged NiMH cell is only 2/3 capacity and as the cell discharges the indicator will stay at about the half-way level for a very long time. The NiMH cells will go flat when the indicator gets to about 1/3. CURRENT NiMH batteries can deliver considerably more current (amps) than alkaline batteries, which make them MUCH more suitable for use in high drain devices such as digital cameras. But because of this high current capability, it is very inportant to carry and store the batteries so that they are not shorted. If an NiMH battery is shorted ... it will get very HOT. Maintain the plastic insulating cover on the batteries and repair as needed.
  10. Considering an earlier post that the sponsor of the bill is from Beaufort, this cache series MAY be a factor. Cemetery Geocaches near Beaufort SC I was in this area last summer but did not do any of these caches. The cache pages are very well done, but the wording of the warning may not be the best public-relations. This post should not be considered critical of these caches, but it seems appropriate to look at this as part of this discussion. I have not attempted to contact the cache owner. To put this in perspective, while doing a geocache last summer on nearby Hilton Head in a historic old cemetery, a large tour bus pulled up. A tour guide gave about 40 folks a guided tour, pointing out the most historically significant headstones and telling the history of the cemetery.
  11. Volume. There are not that many history buffs that go to cemeteries, let alone to a specific head stone. I must disagree. I recently did a geocache NEAR a historic cemetery and I noticed there were several people, amateur historians and genealogists, walking around taking notes from the headstones. These folks were not together, they just happened to be there at the same time. I talked to one fellow and he had notes on every cemetery in the area, and had a published book that had all these cemeteries listed, with all the headstones. At another abandoned cemetery I saw signs that someone had recently uncovered many fallen headstones, and set some of them back up ... probably another amateur historian. There is a lot of interest now in this kind of history, and I think it is CLEARLY A GOOD THING. The more people that appreciate these sites, the more likely they will be preserved. You cannot just leave these old cemeteries untended and expect them to be preserved. Trees fall and damage headstones ... erosion can cause big problems ... and then there are the scavengers and vandals. Of all the cemetery related caches I have done, none had the cache hidden in a way that would cause any damage, either from the cache or from searchers. Most of these had the cache or hint hidden well away from graves. I have seen no signs of damage from visitors, but lots of damage from trees, erosion, scavengers, and vandals. There is no way to go through this life and have no impact on the world. The important thing is that our impact nets positive. I think geocaching nets positive.
  12. Looks like everyone has a different way of doing this. I use the map page of my Garmin GPS76 and the Measure Distance function, which also does bearings. In a problem like this involving intersections, I get a general idea of where the intersection is on the screen, and then plot a couple of points on the bearing near the intersection to define a line from each of the 2 given waypoints. Then I can estimate where the lines cross and put a point there. You can check your accuracy by using the Measure Distance function to check the bearings from the intersection. I think this is similar to what you are doing and it works well if the distances involved are less than a mile. As the distance gets large, you need more than the .5 degree accuracy the GPS gives, since at one mile .5 degree is about 45 feet, at 5 miles 220 feet. When required, I swing the bearing around the point on the map page to see where it changes and use that to estimate fractions of a degree. Oh yeah, make sure you are using True or Mag bearings as specified.
  13. Whether you agree with them or not, organizations like the NRA, which represent minority groups on specific issues, learned long ago to resist ANY legislation which restricts your rights. In this arena, trying to be reasonable makes you a target ... sad but true. Geocaching is a great way to direct folks to historic sites, and make more people aware of these sites and the importance of preservation. If the cache is placed responsibly, it does no damage at all. Some of the caches I have done took me to old cemeteries. Often these old cemeteries suffer from neglect and vandalism, and I have seen signs that those who visited shortly before me had set up fallen headstones. Are geocachers a threat to these sites, or a hope? But on a different perspective, I enjoyed geocaching at Hilton Head last summer. One of the caches took me to an old cemetery that was left in the middle of a high rise development. Where was the SC lawmakers concern for preservation when this was done? I suspect that lawmaker's concern with preservation may be inversely proportional to the finances of the folks who are restricted. If they restrict geocaching in SC, I will be more likely to vacation in FL or NC. But then, Hilton Head is getting crowded anyway, maybe they don't care. FWIW, CharlieP
  14. Although I have an expensive telescoping stick, I usually use one I made from a wooden rake handle. I drilled a hole near the end and tied on a loop of nylon cord. The cord serves several purposes, for additional grip when climbing, to keep the stick from sliding down the hill if I lose my grip on it, and so that I can let it hang if I need both hands. Although I am 5'10'', I like a shorter stick (4 feet) because it is easier to use in brush, and I can let it hang from my wrist when I need both hands. But then, sometimes on a slope I wish the stick were longer. So there are some trade-offs.
  15. Around here (north GA) that is not true, especially near large National Forests or Wildlife Management Areas. I have been scoping out a cache placement where the location is on public land (WMA) that is surrounded by private land on 3 sides. It has taken a lot of research, including looking at county tax maps, to determine a way geocachers can approach the cache without tresspassing. Some of the private land is posted, but only at the obvious entry points.
  16. Just a word of advice based on my own experience. When you find a case of a kid with a really bad attitude, there is a 90% chance that at least one of his parents has a screw loose. And even if one of the parents has all screws in place, they will often defend their wacky kid and wacky spouse. Proceed with caution.
  17. For some locations it is appropriate to make finding the parking area part of the hunt, in fact it may be the major component of the search. For some other locations, not specifying the correct parking area may lead to geocachers tresspassing or encountering dangerous conditions. Cache owners need to consider the possible approaches that may be used by searchers, and post parking coords and other instructions when appropriate. FWIW, CharlieP
  18. I have posted to other boards where posts made only to elicit emotional responses or deceive become so prevalent that the board becomes useless. This kind of thing is often called "trolling". It is one of the best ways to drive off all of the sincere folks and leave the board to a small group of neurotics.
  19. I wonder what happened to the 4 big radial engines? You can't carry one of those in a backpack.
  20. My favorite caches tend to those that involve a hike in a remote or tranquil area that takes me to an interesting, historical, or scenic location. But I also enjoy cache hunts that have a creative twist, or some aspect that tweaks my curiosity. I also appreciate some of the caches placed near major highways that allow me to take a break from driving on long trips. My least favorite cache hunts are the Drive By Micros in Uninteresting Locations (DBMUL), and caches that require extended searching in a public place, esp. if it invites an encounter with law enforcement officers. I have begun skipping these altogether ... it just isn't fun.
  21. Seems like many of the arguments against a rating system are based on specific assumptions on how it would work ... or not work. I think a procedure/system could be set up that addresses all of these issues. For example, it may not be necessary to allow negative ratings, or to have all geocaches rated. If cache placements continue to prolifierate, at some point the lack of a way to identify the better caches will probably affect participation. You have to consider that many folks decide if they like an activity based on their first few experiences. But hey, maybe we have enough folks in this game already.
  22. With the proliferation of geocaches in the last year, the rating system issue has a lot more validity. I think many of us are using logs to evaluate and select caches, but this is a tedious process. It would be great to be able to pull up all the caches in any area that were considered special. But I would also like to see a separate sytem whereby caches are rated, perhaps by the owner, in terms of characteristics such as: driving distance, hiking distance, historical significance, scenery, and others. I suppose there would be some disagreements about these characteristics, but any info is better than none, and I doubt that anyone would consider a parking lot scenic or historic. How many of us have gone on a vacation and done several geocaches, and then discover later that we "missed" the best caches in the area.
  23. I also agree, G7toWin will do screen captures on Garmin GPSR's. It will also load waypoints and tracks into Street Atlas from the gps or from downloaded files ... this is a great feature.
  24. I have done this the hard way, by selecting a number of points along the route, allowing some overlap of the circles, and then let gpx2html eliminate the duplicates. It works, but is tedious. It would seem that there are a couple of good ways, or more, to do this. First of all, for major interstate highways, a data base of coords could be set up so that the user simply specified the highway, a start and ending point, and a lateral distance that would apply on both sides of the highway, and the software did the rest. For less well traveled routes, the user could specify a number of points and a lateral distance, and the software would create rectangles between the points and list all the caches in all the rectangles. It would be great if the input would work graphically from maps, but that's asking a lot. FWIW, CharlieP
  25. I think the accuracy of different units will be similar IF they are able to receive about the same number of satellites and there is no multipath error. A GPSR with a better antenna may be able to lock onto more sats than a unit with a less effective antenna, especially under trees, and this can make a big difference in accuracy. Of the variables that affect accuracy, I have found mutipath error (signal bounce) to be the most troublesome, because the GPSR may report an EPE which is flat wrong. It is frustrating to have the unit tell you you are within 10 feet of the position, with a 20 foot EPE, and then tell you you are 80 feet away, with the same EPE. When the GPS acts like this, I don't rely on the output. In places where signal bounce occurs, two GPS units side by side may differ by 60 or 80 feet, both reporting a 20 foot EPE. FWIW, CharlieP
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