kalafut
commented
3 years ago Hi! Thanks for the interest in the project. You're right that this simulation is much cleaner/simpler than the real thing. The full broadcast spec is fairly elaborate (have a look even at the Wikipedia overview). This was a "weekend" project that turned into a "lots of weekends" project, and when I was writing it there was a good chance no one would even find it, so I didn't end up going into the really minute details.
The double clicks have do with with some UT1 offset (difference between UTC and Earth's rotation, or something like that):
Between seconds one and sixteen inclusive past the minute, the current difference between UTC and UT1 is transmitted by doubling some of the once-per-second ticks, transmitting a second tick 100 ms after the first. (The second tick preempts other transmissions, but does not get a silent zone.[13]) The absolute value of this difference, in tenths of a second, is determined by the number of doubled ticks. The sign is determined by the position; if the doubled ticks begin at second one, UT1 is ahead of UTC; if they begin at second nine, UT1 is behind UTC.[14]
WWVH transmits similar 5 ms ticks, but they are sent as 6 cycles of 1200 Hz. The minute beep is also 1200 Hz, except on the hour, when it is 1500 Hz.
Those actually might not be too hard to emulate, and I agree that they're part of the audio "character" that you'd be used to after hearing the real WWV. Same with the BCD code and the start of some minutes which you can hear.
I'll keep some of these in mind, especially since the project has ended up getting regular traffic.
Apologies. This isn’t an issue, per se, but there doesn’t seem to be a discussion forum for this project.
Like you back in my shortwave radio days I used to listen to WWV constantly; I found it to be hypnotic. So I was fascinated to discover this project. Thank you!
In any case, my memories are of slightly different tone patterns. This YouTube video seems to match my memories.
https://youtu.be/Smt8DWRbDfI
It has a more complex pattern of tones, including double ticks at 9 and 10 seconds, and then a pattern of shorter and longer ticks which I haven’t quite sussed. Can anyone explain them?