> However, I've not been able to find a discussion about the best time > source, assuming one is in the U.S. I know that jitter is bad, but > many GPS sources, especially USB-connected, are very bad when it comes > to that... and yet supposing that I am ready and willing to spend > money on purchasing a GPS that my computer, ntpd, and the pool will > love, I have no idea what to get. Also I'd rather avoid having to > solder and whatnot -- I know that there are "bare" GPS devices with > just a raw wire hanging out of them, but I am probably not hardcore > enough to deal with it.
First off, you can make a valuable contribution to the pool without a local refclock (GPS or otherwise). Have you setup a system to use several nearby servers? What sort of accuracy are you seeing? Assuming you are a bit crazy (like many of us) and want to make your system as good as you can... How much cash are you willing to spend? How good do you want/need? For a good unit, you probably want a PPS signal. That will/should get you well under millisecond accuracy. It will be hard for somebody without a good clock to notice that you are that good. My straw man for an afordable GPS unit is the Garmin GPS 18-LVC for under $100. It takes some soldering. Can you find a friend/neighbor to help with the soldering? (If the available directions aren't good enough we can fix that.) Even if you toss in a bottle of wine or dinner, the cost will probably be cheaper than most other GPS units. Where do you live? Maybe somebody on this list with a soldering iron is close enough to help. I'm in silicon valley. GPS needs a signal from satellites. How well your unit works will depend on where you locate it. Mine works pretty well inside my house. I haven't been looking for no-soldering type units. I expect they will be a lot more expensive. If you want an external clock, you might look for WWVB receivers. (I don't have any to recommend.) I wouldn't expect them to be as accurate as GPS but they might be good enough to be interesting. Where do you live relative to Colorado? ---------- > Do you suppose that the DB-9 version (which comes with a cigarette > lighter adapter) is less precise/more jittery/etc.? It doesn't have a PPS signal, hence won't be nearly as good. It also needs power from the cigarette lighter gizmo. Do you have a handy place to plug that in? -- The suespammers.org mail server is located in California. So are all my other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited commercial e-mail to my suespammers.org address or any of my other addresses. These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ timekeepers mailing list [email protected] https://fortytwo.ch/mailman/cgi-bin/listinfo/timekeepers
