The propagation delay depends of course upon the distance from the transmitter in Fort Collins. About 6.3mS for me in London Ontario.
The way a GPS system works, each satellite transmits its orbit and time, and the receiver takes a number of satellite signals, all arriving at slightly different times due to their different propagation distances, works out the receiver position, and then calculates a time correction. ?Modern receivers get it right to within a handful of nanoseconds.
You can compare the GPS PPS with the arrival time of the WWV and WWVB signals and watch the ionosphere move.
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On Sep 18, 2023, at 12:37, Jerry Moyer via groups.io <ac5jm@...> wrote:
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I would think that the accuracy of WWVB would be the absolute most accurate time source since it is controlled by a Cesium clock at the National Bureau of Standards itself. ?It is the primary source for all US time standards . ?There could be a slight amount of propagation delay I suppose but there also would be from a satellite.
-Jerry
On Sep 18, 2023, at 10:00 AM, William Smith <w_smith@...> wrote:
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Back in the dawn of time we had a WWVB receiver that we checked our lab standard with, and WWVB was only stable overnight in MA. ?I'd have to say if you can get a good (ground wave) signal 24x7 you might be able to lock a local standard to it, but otherwise you might have to watch the reference and tweak your standard occasionally, as we did.
I'd use a GPSDO, those are easy, cheap, and usually pretty solid.
73, Willie N1JBJ
On Sep 17, 2023, at 5:27 PM, Jerry Moyer via groups.io <ac5jm@...> wrote:
There are several cheap WWVB receivers available.? Has anyone successfully implemented WWVB as a 1pps time source rather than GPS for QRP Labs kits?? How did you do it and what are the pros and cons between WWVB and GPS?? One that comes to my mind is a clear view of the sky is not required with the WWVB 60kHz signal.? A disadvantage might be potential interference to 60kHz from LED light dimmers and such.? Which is more reliable?? Maybe have one automatically back up the other?
-Jerry AC5JM
