![]() ![]() These are mainly related to atmospheric conditions from high in the atmosphere to anything affecting only local conditions. In the case of the extremely weak GPS signals, there are many things that will affect this. That is, essentially, the time it takes for the signal to travel from sender to receiver. Latency is always the killer when trying to sync two or more devices together. However, there are a few minor hitches in this that need to be understood. These are highly stable clocks that were originally calibrated with UTC, so the signals that originate from them can be considered a good sync link back to UTC, and therefore a good source of synchronization on their own. The GPS satellites each contain three Stratum One cesium atomic clocks in them. It's the Time & Date information that matters here. The NMEA 0183 standard sentences allow the GPS receiver to send information related to Time & Date, Geographic Position - Latitude/Longitude, and individual satellite information. The data in those sentences are defined by the NMEA 0183 (National Marine Electronics Association standard 0183) or NMEA 2000. ![]() The data that is sent from the GPS receiver is a series of standard "sentences" that contain defined data. However, they can be used as a crude substitute in the field if one has the necessary software and is aware of the limits. Consumer GPS receivers that are used primarily for navigation or geolocation functions are not designed to provide time synchronization. Here are some other clock displays for the Windows desktop."Consumer GPS signals. My observatory has been running the one shown at the link below for a few years and it works flawlessly. You will need the appropriate GPS hardware for this. If you live in an area with poor internet connectivity, NTP for Windows has the ability to synchronize the system clock to a local GPSDO having a 1 PPS output. "Dead on" means that when I listen to WWV on an Icom R75 and watch the UTC Clock display, there is no perceptible offset, so the system clock stays accurate to better than perhaps a few tens of milliseconds. The PC clock stays dead on with what I hear from WWV. David Taylor maintains a very nice set of instructions (link below) for this utility. Meinberg Radio Clocks GmbH has released this as an open-source freeware utility that runs in the background as a service, not as an application. One solution is to synchronize the system clock with time servers traceable back to NIST. For radio astronomy, my computers have a time zone of "(GMT) Cooridinated Universal Time" or "(GMT) Monrovia, Reykjavik", neither of which change with daylight saving time.Ī nice clock display is of little use if the computer's system clock in inaccurate. Note: this app pulls the UTC time from your system clock, so the time zone in Windows must be set properly. Using the app is equally straightforward: click & drag the display to move it around, right-click to bring up the options. To install, simply download the zip file, extract, and run the setup program. ![]() ![]() It should work on pretty much any Windows computer running Windows XP or above. This is not very good when you want to see the UTC time from across the room.Īs an excuse to learn Visual Basic 2010, I wrote a clock application that includes an option for a larger display. Unfortunately, some of their displays are a little small on modern large computer monitors. There are other apps which do a great job of this. Sometimes it's handy to have a clock display that shows the time in UTC and LMST. UTC Clock 1.2 for Windows UTC Clock 1.3 for Windows | Home ![]()
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