email@example.com (Leigh Palmer) writes: > >assume that a narrow band audio filter would really make those second > >ticks stand out from the background noise that so often plagues HF > Narrow-band filters seldom sharpen wide band material, like ticks. I am operating outside of my range of experience, but the "Time and Frequency User's Manual" seems pretty clear on this matter. "Tick" is apparently a euphemism, or approximation to the impression of the received sound. In fact, the manual actually uses the word tick with double quotes around it, "tick". Each WWV tick consists of 5 ms of 1000 Hz (WWVH 1200 Hz, CHU 300 ms 1000 Hz). So, even if there is some spread, the received audio frequency of the signal should be highly concentrated in the region of 1000 Hz. Cheers. Walter Nissen firstname.lastname@example.org -81.8637, 41.3735, 256m elevation --- Bad attitude: I don't like this forest. It's dark and creepy. Dorothy, The Wizard of Oz Good attitude: Oh, look, there's a clearing. See how beautiful the night sky is.