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Team CowboyPapa

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Everything posted by Team CowboyPapa

  1. Roger that! In my aerospace job I was doing FII in '62.
  2. Accuracy and precision are not the same thing. Can you provide the calculation of combined accuracy? I calculate normal distribution to quantify precision.
  3. Can estimated combined accuracy be also described as precision with the quantitative value being standard deviation?
  4. When that is said in my presence, my response is: "I'll be the judge of that!" Yes, I was on the Delta II Expendable Launch Vehicle Team. I worked the launches of the current, 2nd generation, GPS satellites, 1995 - 2002. If your GPSr's work, I made no mistakes. Actually, we did not use the term "rocket science" back then.
  5. Is this not a geocaching forum? Can the PLB be used for geocaching after downloading cache descriptions?
  6. Confucius say: "What go up, must go down".
  7. What is the defintion of "a ton of people"? 10 geocachers weighing 200 lbs each? Or?
  8. The SD card can be removed from a PN and opened in a PC after insertion. Copy the geocache files (gpx format) into the folder named "waypoints" on the SD card.
  9. I have Topo 10 active on my Windows PC and my PN-40 works fine with it. I download my Pocket Quries to PC, upload to Topo 10 Draw folder, then transfer to Topo 10's Export folder as *.gpx files and then sync to PN-40's Waypoints folder.
  10. Find a store that will let you try one out in the parking area and have a friend hide a test cache there.
  11. @Mineral2 I thank you very much for the suggestion above. I now have a GPSMAP 66i, and tested with the settings you provided. Prior to the test, I modified the Trip Computer page: (1) I retained “Elevation” in the upper most left column slot, (2) I replaced the next slot down with “GPS Elevatiom, (3) I replaced the upper most right column slot with “Barometer”, and (4) I replaced the next slot down with “Ambient Press.”. I then changed the Auto Calibration to “Off” and the Barometer Mode to “Fixed Elevation”. Additionally, I manually selected the Calibrate Altimeter Method of Current Elevation to Calibrate to 200 ft. Walking along the level Green Belt (about 100 yards off the shore) in Sunset Beach, CA, I recorded about a ½ mile track. As I walked the Elevation slot displayed a constant value of 200 ft. while the GPS Elevation slot displayed between 9 ft. and 15 ft., which was reasonable. After concluding the walk, I synced to the Explore app on my phone and viewed the elevation profile as a constant 200 ft. Conclusion, these Altitude settings resulted in the barometric elevations being recorded and not the GPS derived elevations. My next test was to set the Auto Calibration to “Continuous” and the Barometer Mode to “Variable Elevation”.Additionally, I manually selected the Calibrate Altimeter Method of GPS Altitude and selected “Calibrate”. I then drove up and down a hill, while not recording a track, of about 50 feet and noticed that the Elevation and GPS values were identical. Now, selecting “Start” to record the track, I noticed that the values for Elevation and GPS Elevation varied by a few feet, with the Elevation being a few feet higher than the GPS Elevation values/ Actually, they both decreased going down the hill and increased going up. On basically a level street, they both went up and down slightly, with the Elevation values always slightly higher than the GPS Elevation values. Conclusion: Referring back to the top, with the two top fields, on the left, being Elevation above GPS Elevation, it is the top most, Elevation values that always are recorded. When Altitude calibrated to GPS and Continous selected, the top most value is GPS. However, when not recording, both fields are identical while there are slight differences when recording.
  12. 10-4. 4 decimal places on a foot are different than 4 decimal places on an inch.
  13. AFAIK, elevations are barometrically determined by default, GPS calculated may not be an option. If so, the -1165m might have resulted from an erroneous, too high ambient pressure. Pressure vs. altitude here: https://www.digitaldutch.com/unitconverter/pressure
  14. WRT to the thread title: Depends on how many there are. If there are 100 or more Garmin engineers, yes, I am smarter than at least one!
  15. Team CowboyPapa

    PN60 firmware

    OK Jim, two things here, PN-60 update to record correct date and cable. 1. PN-60 Update: IM(not so)HO, there two issues that will occur prior to update, wrong year on recorded tracks and on recorded waypoints. 1a. For tracks, the 1999 will be noted in the track title, or file name, which is easy to modify. Also, it will be in the recorded data for each time slice. Now this is not usually a big deal; however, to fix it I would open the file with MS Word, or equivalent, and then do an Edit, Search and Replace all occurrences of 1999 with the current year. 1b. For waypoints, the 1999 will be recorded internally; I would open the file with MS Notepad, or equivalent, and delete 1999 and then replace with current year. 2. Cable: Lack of cable has two impacts, data management and recharging internally located battery. 2a. With the exception routes created externally using the DeLorme Topo software, all other data can be imported to or exported from the folders on the SD card. Waypoints and tracks both ways and maps imported. Routes can be created on the PN, but really not very feasible. 2b. Only AA cells, either rechargeable externally or non-rechargeable must be used. The DeLorme internally rechargeable battery pack can only be recharged with the proprietary cable. I use only the commonly available cells nowadays as my DeLorme rechargeable has expired. Any further info needed, let my know, and I will be glad to provide. AKA as CowboySlim
  16. Team CowboyPapa

    PN60 firmware

    I am very grateful for the link above. Initially, I did not take the advice to remove the SD card literally, and the update did not implement although I pasted it into main storage. Then, I finally decided to remove the SD card, reinstall batteries, and restart. Surprisingly, the update took place and now v3.7 is active. Thanks, Capt. Bob!
  17. Team CowboyPapa

    PN60 firmware

    As with all PNXX users, all current waypoints and tracks are recorded and saved with the 1999 date. AFAIK, I do not see any resultant decrement in its functional capabilities. However, for those that I wish to retain as gpx files, I use WordPad to simply change the date to 2018.
  18. Team CowboyPapa

    PN60 firmware

    I have that version on mine; however, I do not notice any resultant software glitches.
  19. Just collected a waypoint with my handheld GPSr. 10 US GPS satellites acquired with EPE ±6 feet. If one additional US GPS acquired, how much would the EPE be decremented? One additional GLONASS? One additional Galileo? Waypoint collected near geocahe GC3N62E.
  20. Another instance of the "Law of Diminishing Returns". Or, has it been repealed by the DoD or NASA?
  21. OTOH, I did use "h" for both VAFB and CCAFS flights. The pressure at the bottom of the liquid propellant tanks was p=ρgh.
  22. Running launch vehicle preflight trajectory computer simulations, I can't recall that which I did use to represent height or altitude. However, if I did use h or H, I was not terminated.
  23. Vertical Error Analysis I will firstly pose an analogy that all should find reasonable and the provide an example applicable to the elevation errors. Newborn weighed shortly after birth at hospital delivery room as 10 lbs. Newborn, infant scale label specifies accuracy as ±1.00%. Consequently, baby could have a weight between 9.9 and 10.1 lbs, or an error of ±0.10 lb. Next day, that scale is not available. However, quite accessible is an adult scale with the same ±1.00% accuracy, but it cannot display less that 150 lbs. Therefore, a custodian is asked to get on the scale and displayed weight is 200 lbs, or the actual weight could be between 198 and 202 lbs (±1.00%). Custodian is then handed the infant and the display is 210 lbs, or actual weight between 208 and 212 lbs (±1.00%). Subtracting, the possible range values (212 – 198 and 208 – 202) for the weight of the baby yields the possibility of between 6 and 14 lbs, or ±40%, approximately. Now, applying the issue of accuracy to instances of subtracting one large value from another to obtain a small remainder to a GPS determined elevation, let's look at my backyard which the average 40 GPSr readings yields 7 feet. AMSL. 1. GPS satellite elevation of 12,550 miles, or 66,264,000 feet 2. GPSr calculates distance above my back yard of 7 feet less, or 66,263,993. 3. What % error would ensure an accuracy of ±13 feet, or elevation between -6 feet and 20 feet? 4. Or, does not that subtraction question apply to elevation determinations? 5. If it does apply to vertical distances, does it also apply to horizontal distance calculations? DISCLAIMER: Do not ask me to prepare your income tax document.
  24. Nice attempt, but not what I will post in a while.
  25. IM(not so)HO, I would not discuss both horizontal and vertical accuracy in a paragraph including both. Characterizing the normally distributed random errors of both quantitatively by their standard deviations, I have a four times greater value for vertical than for horizontal. Consequently, I prefer to discuss them individually and separately. There is a calculational consideration regarding vertical errors that does not apply to horizontal. DISCLAIMER: I do not have a university degree in mathematics.
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