TeamRJJO

The WAAS carrier frequency is that same as that of the GPS signal, so if the flare disrupts GPS signals (which is unlikely, by the way), WAAS will be disrupted as well. Peace, TeamRJJO

Okay, I checked out a few places that I do not think were set up well for this type of event (Bob Evans, IHOP - too difficult to sit together, long lines, etc.), a couple of family owned places, bagel shop - too small) These were mainly in the Springfield area. Can anyone recommend any places they think may work....in Alexandria, Fairfax, Reston, Woodbridge? Ideally, would like a setting where folks could come in and sit at a number of tables that are close to each other or set off together, ... folks can eat or not or just have coffee...not wait in long lines, be conducive to socializing and not be pushed out quickly due to long lines.

Thanks to each of you for your help! I am definitely toying with the idea...in the Springfield area. There are many old and new caches to be found after breakfast within 5 miles or so. BigCall it looks as if it has been about three years since the last NoVa breakfast. We have enjoyed the little contact we have had on the trails with other caches. We have had fun with your caches BigCall Thanks! Jenn (Team RJJO)

We are new to the game and would love to actually meet some of our local geocachers. We noticed that there is a breakfast gathering in Charlottesville, VA for cachers and the idea is a great one. Borrowing from this theme, we were wondering if this has been done in Northern Virginia before and if there is any interest for a gathering such as this. The plan would be to meet at a local diner/restaurant in the morning to have coffee or breakfast and meet other cachers. Is anyone interested?

Probably a bit, at least. Having the receiver on gives the internal clock a chance to flywheel off the GPS signal for longer, reducing position error. Peace, TeamRJJO

I'm not really sure how many commercial aircraft use WAAS. Many use LAAS -- local-area augmentation systems. Quite a few airposts use pseudolites to augment GPS. Pseudolites are basically beacons putting out GPS-like signals to augment the coverage provided by the satellite system. Peace, TeamRJJO

Position error fromthe satellites is given as follows: Error = RMS URE x GDOP where RMS URE is the root mean square average of the navigation error coming from each individual satellite and GDOP is dillution of precision as a function of satellite geometry. In general, the URE for a satellite gets higher, thr longer it has been since the satellite was given a fresh navigation upload (usually, an upload is done once every 24 hours). GDOP changes constantly as the satellites move in their orbits. "Ideal geometry" is one satellite directly overhead, and three on the horizon spaced at 120 degrees apart. So, in theory, it's possible to have satellites with fresh uploads, but bad geometry, and get worse position error than satellites with old uploads, but great geometry. You won't have a whole lot of insight into URE, but there are several utilities out there that will allow you to plot DOP over the course of the day using the satellite almanacs as input. There are other contributors to position error as well, such as interference, multipath effects, etc. But all else being equal, geometry and URE are the main contributors. Peace, TeamRJJO

I think "oblate spheroid" is the approved industry term for "squished bumpy pear."

The two are really not related. The motion of the Earth's axis has two parts -- precession and nutation. Precession is the motion of the axis in a large circle over a roughly 26,000 year period. Nutation is a harmonic with a roughly 18.6-year period, superimposed on top of the precession circle. Although the axis moves, the equator always remains fixed with respect to the axis. The equator does move with respect to the ecliptic, but since GPS coordinates are referenced to an Earth-centered, Earth-fixed plane, this movement of the equator with respect to the Earth-Sun line is transparent to GPS. NGA issues a new map datum every 5-7 years. This is simply a function of measurements being refined enough to warrant the issue of a new datum. It's not tied to any natural event. Peace, TeamRJJO

Heh, heh.....this occurred to me about 4 pages ago: the Hagis guy -- on whose behalf this whole thing erupted -- probably left the forum and went out drinking or sleeping or geocaching HOURS ago.

We would like 4 or 5 coins when made.

Well....that appears to be the case here. I just checked, and the guy has moved nearly 2000 miles away. He has not turned any of his caches over for adoption, but neither has he responded to notes left on at least one of them, speculating that the cache has gone missing. So what is the right thing to do here, assuming that this still isn't found for another few months? Or about the rest of his local caches for that matter? (Yes, I do understand that e-mailing the guy is an appropriate thing to do, but in the case above, he's not exactly in a position to go check on the status of his cache anymore). Peace, TeamRJJO

This thread doesn't strike me that way at all. Someone raised a good question if we know of an archived cache which is physically still out there, what are we supposed to do about it? As an example, there's a lake near us which is currently saturated with caches (as a result of the 528' rule). However, the owner of one of these caches is getting ready to move, if he hasn't already. Given that this lake is "prime caching real estate," if no one adopts the cache, what happens? Is someone supposed to go get it and remove it? Who does this? Peace, TeamRJJO

Believe it or not, when I was working in the 2 SOPS (the AF unit that operates the GPS constellation), we actually had to field this question. It was a long time ago, but as I recall, someone actually did a study on this. The idea was that on the moon, GPS signals would come from the satellite antenna sidelobes and possibly even from RF emmissions from the back of the satellites. I think the conclusion was that while the signal strength from these sources might be strong enough, one would need some method of transforming Earth-centered coordinates into something that would be useful on the moon. And obviously, if you were on the side of the moon facing away from the Earth, you'd be comepletely unable to receive the GPS signal. Peace, TeamRJJO

Another way of stating it would be that scintillation occurs during (large) fluctuations in TEC. Peace, TeamRJJO

There's two parts to the answer: 1. Since WAAS broadcasts on the same frequency as the GPS signal we all use, if a storm was severe enough to cause ionospheric scintillation that takes out the GPS signal, it would likely be a problem for WAAS as well. 2. What you would see during scintillation would NOT likely be navigation errors. The bit errors that scintillation causes also make the received navigation message fail the built-in parity checks. So, if your user set is designed in accordance with the GPS payload-to-user specification, your receiver wouldn't use that satellite's signal at all. In reality, your receiver would likely have a tough time maintaining signal lock on the satellites, especially those at lower elevation angles. But again, this is a very localized effect. Peace, TeamRJJO

Thanks for the replies!

For what it's worth..... During my time in the GPS master control station, we observed somewhat limited effects of ionospheric scintillation on the GPS signal. The effects were most pronounced at locations close to the equator, during local sunset, between the months of October and January. At the monitor station in Colorado Springs, we saw almost no impact. So in a nutshell, I'm doubting that North American cachers are going to see much of an effect from this storm. Peace, TeamRJJO

the rules. We have noticed several times in our area when a TB or Jeep TB is left in a cache that folks who have already found the cache go back and grab the bugs and then post a note that they took them. They must have the caches on their watchlist. I know the Jeep TBs are a hot commodity. Is this okay to go back to an already found cache or even one that you own to grab TBs...does everyone do it. How does that work? Thanks for your help on this...again just wondering what the geocaching etiquette is for this type of situation.

The current signal structure is precisely that same as it was when S/A was on. You wont' see any new civil user signals for another 3-4 years. Peace, TeamRJJO

Heh, heh....if it was placed anywhere near my location, it would get found and smoked well before the environment could ruin it. Peace, TeamRJJO

I'm a big MythBusters fan, and am embarrassed to have forgotten about the CD test. Thanks for jogging my memory. I know they microwaved CDs, but I don't think they froze any. The freeze is of interest to me, being in Chicago. I remember they had to spin the CDs to a crazy RPM to get them to start warping. I'm pretty sure CD players and DVD players run slower than the 52X CD-ROM drives in computers. When listening to and ripping CDs on my computer, I can tell just from the sound that the drive isn't running at full speed. And I don't think the MythBusters got their "normally-aspirated" CD-ROM drive to break any CDs. I think the rule of thumb in this case is to let the CD from a cache warm or cool to room temperature before using. Guys, Check out this link: www.cdrfaq.org These folks have done all sorts of environmental testing on CDs and CDRs. The main thing you have to worry about is the dye used in cheaper brands of CDRs going bad when exposed to extreme temperatures. If that happens, the CDR is rendered unreadable. Peace, TeamRJJO

Just trying not to harsh out on any of my fellow geocachers. Yeah, compilation discs are not legal according to the letter of the law. Neither is going 1 MPH above the speed limit. Do I think anyone from the RIAA is going to get pissed off over a couple of CDRs left in the woods? Not at all. So if someone enjoys making them and leaving them in caches I don't see a big problem. Peace, TeamRJJO

Thanks! We look forward to joining you guys when something is planned.

Crystal Sound's post is correct as it pertains to copying official releases. Trading original factory-pressed CDs is perfectly legal, as is making copies of material over which artists/record companies have not chosen to excercise copyright. This would include live performances by "trade friendly" or "taper friendly" artists such as the Grateful Dead. So there is nothing suspect about any of the CD exchange caches out there. Compilation discs of officially released material are technically not legal, but since no money is changing hands, and we're talking about such small numbers of discs, I doubt anyone is going to get in a twist over using these as swag. Peace, TeamRJJO