b...@evoria.net said: > I've noticed the same. In looking at the Satstat program, it appears that > when you enter a location, that's only treated as a hint. There is also a > value you can set to zero that supposedly tells it to come up with the last > hold value. It didn't seem to work for me. I've finally got my location > and power cords in more or less permanent locations, but things happen. > And, I won't be getting a UPS for it for quite some time. Maybe someone > else has the secret sauce.
There are several ideas tangled up in this area. If the GPS receiver has a recent enough almanac and you tell it the time and/or location, it can get started much quicker. The satellites broadcast on a known frequency, but the Doppler pushes that a long distance relative to the bandwidth. The almanac and time+location lets it compute which satellites are visible and the frequencies to listen on. That shortens a long search. Most/many GPS receivers have a watch crystal and clock and battery (or supercap) for this purpose. GPSDOs are usually used at fixed locations. If it saves the surveyed location it can avoid another survey on power up. You can save the surveyed location in flash so a battery isn't required. Some GPSDOs automatically save the results of a survey. Some don't. The Z3801A does an automatic save. The TBolt requires a command to save it. It can also save the GPS-UTC offset so it can deliver correct time in UTC without waiting to get that info from a satellite. -- These are my opinions. I hate spam. _______________________________________________ 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.
