On Monday 16 October 2006 12:40, Vassilii Khachaturov wrote: snip > > The BIOS and system time agree with "WWV" and an Atomic Clock. > > What is "WWV"? there is no such airport.
WWV, WWVB and WWVH are the U. S. National Institute of Standards and Technology (NIST) time and frequency radio signal stations. WWV (male voice) and WWVB are located in Fort Collins, Colorado. WWVH (female voice) is located on the Island of Kauai, Hawaii. WWV and WWVH broadcasts on 2.5MHz, 5MHz, 10MHz, 15MHz and (WWV only) 20MHz. These are amplitude modulated audio time signals that are human understandable (time announcements with beeps). WWVB broadcasts at 60KHz with a binary signal with a 1 bit per second rate with one complete time signal every 60 seconds. WWVB is the signal used by those "atomic" clocks that you can now buy so inexpensively in many stores. All of these radio signals are regulated by the actual atomic clocks that NIST and the US Naval Observatory maintain and in general these signals are accurate to about 4 nano seconds at the antenna. Away from the antenna WWVB is considered more accurate since reception is always by way of a ground wave and propagation delays are consistent and much more predictable than WWV or WWVH signals at any given reception location. For many years WWV was considered the authoritative source for time and frequency calibration information. In the early 1970s international standards were established and there are now similar stations in other parts of the world including England , Germany, China, Canada, Switzerland, France, and Japan. All of these maintain their own atomic clocks and coordinate all of these clocks (including NIST and the US Naval Observatory) to keep them in sync. By the way WWVB is considered a primary time source for NTP and any time server that uses WWVB to discipline it's clock is a stratum 1 NTP time server. Most user machines using NTP will be stratum 3 or higher. > > > The Airport difference could be a source of the problem. Does IAH > > (Houston) exist? > > It does, and it is supported by flightgear. I assume you have the local > scenery downloaded for it. > > Vassilii > > > ------------------------------------------------------------------------- > Using Tomcat but need to do more? Need to support web services, security? > Get stuff done quickly with pre-integrated technology to make your job > easier Download IBM WebSphere Application Server v.1.0.1 based on Apache > Geronimo > http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 > _______________________________________________ > Flightgear-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/flightgear-users ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Flightgear-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/flightgear-users
