Greenwich Time Signal a station jingle during Jakki Brambles' early show and Simon Mayo's breakfast show. This was not strictly crashing the pips as they were not intended to be, or mistaken for, an accurate time signal. At 8 am on 17 September 2008, to the surprise of John Humphrys, the day's main presenter on the "Today" programme, and Johnnie Walker, who was standing in for Terry Wogan on Radio 2, the pips went adrift by 6 seconds, and broadcast seven pips rather than six. This was traced to a problem with the pip generator, which was 'repaired' by switching it off and
Time signal signal travels increases the uncertainty of the time signal on a scale of milliseconds. Radio time signal stations broadcast the time in both audible and machine-readable time code form that can be used as references for radio clocks and radio-controlled watches. The audio portions of the shortwave WWV and WWVH broadcasts can also be heard by telephone. The time announcements are normally delayed by less than 30 ms when using land lines from within the continental United States, and the stability (delay variation) is generally < 1 ms. When mobile phones are used, the delays are often more than 100