Hi I guess it comes down to “how good is good enough?”
With any L1 only system, you are up against uncorrectable ionosphere numbers in the >=10 ns range. At 3 ns meter that is a > 3 meter “variation”. The ionosphere does tend to correlate with that big light in the sky, so averaging over multiple days can address it in a position solution. Your TBolt will still wander around, since it’s loop time constant is << 24 hours. If you are trying to take 12 -2/+40 ns per day down to 10 -2/+40 ns per day, then sure a ~5 mm accurate position will be better than a ~1 M location. It’s doubtful that there will be any measurable change in the TBolt’s output as a result. For $100, sure it’s not an expensive thing to try. I ummm ….. errrr .. seem to have a room full of antennas. My point is *not* let’s not do this. The point is that everybody does not need to run right out and go antenna crazy (like me). The TBolt works quite well on a proper outdoor timing antenna that has a very good view of the sky. Those antennas are nice and compact and sell for < $50. Bob > On Apr 23, 2015, at 3:04 AM, Mark Sims <hol...@hotmail.com> wrote: > > At least with a Tbolt, they do help... and quite a bit. When I was writing > Lady Heather's precision survey code I tested it with several antennas > (comparing the results to a cm level L1/L2 survey). The Leica antenna and a > couple of other survey grade/choke ring antennas were, by far, the best > (results with a foot or so). Cheap patch antennas were the worst (with > maybe 5 foot errors). > > Some small L1 only survey grade antennas did pretty well... a couple of feet. > They are about 6 inches in diameter and and inch thick and very light. I > use one as my standard antenna. > > ----------------------------------- > It’s not real clear that they have a significant advantage for L1 only > operation with a Z3801. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
