HBG was a

low frequency Low frequency (LF) is the ITU designation for radio frequencies (RF) in the range of 30–300 kHz. Since its wavelengths range from 10–1 km, respectively, it is also known as the kilometre band or kilometre wave. LF radio waves exh ...

time signal A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day. Church bells or voices announcing hours of prayer gave way to automatically operated chimes on public clocks; however, audi ...

transmitter In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna (radio), antenna. The transmitter itself generates a radio frequency alternating current, which i ...

for the Swiss time reference system. It transmitted on 75 kHz with 20 kW power, and was located in Prangins, Switzerland. Due to the cost of urgently needed renovation for the ageing antennas, and the ease with which all existing users could switch to the DCF77 time signal, the Swiss Federal Government decided to shut down HBG at the end of 2011. HBG transmission ceased on New Year’s Day 2012 at 07:00:13.2 UTC. On 6 September 2012 at 12:02:00 UTC both antenna towers were demolished by controlled explosives."La fin des antennes de Prangins en live" - 20min.ch
/ref> The HBG transmission format was very similar to DCF77. At the beginning of each second (with the exception of the 59th), the

carrier Carrier may refer to: Entertainment * ''Carrier'' (album), a 2013 album by The Dodos * ''Carrier'' (board game), a South Pacific World War II board game * ''Carrier'' (TV series), a ten-part documentary miniseries that aired on PBS in April 20 ...

signal was interrupted for a period of 0.1 s or 0.2 s, which corresponded to a binary "0" or "1". The transmission of the minute, hour, calendar date, day of the week, month and current year was achieved by means of a

BCD code In computing and electronic systems, binary-coded decimal (BCD) is a class of binary encodings of decimal numbers where each digit is represented by a fixed number of bits, usually four or eight. Sometimes, special bit patterns are used for ...

identical to that of DCF77. Like DCF77, the carrier was not interrupted during the last second of each minute. Differences from the DCF77 time code: * The carrier frequency. * Phase modulation was not included. *

Amplitude modulation Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to ...

was done by disabling the transmitter (0% amplitude) rather than reducing it to 15% amplitude as DCF77 does. * Announcement bits warning of impending time zone changes or leap seconds were sent 12 hours in advance, rather than 1 hour. * The first pulse of each minute was not a standard 0 bit as DCF77 sends. Instead, it was a double pulse, two 0.1 s interruptions separated by 0.1 s of carrier. A triple pulse signalled the start of a new hour, and a four-pulse signal was transmitted at noon and midnight. It is understood that this frequency is now available in Europe, as well as any other part of the world, for time signal dissemination.

References

External links

Information page on Swiss federal office of metrology (METAS)Pictures of the HBG transmitter in Prangins, Switzerland (emetteurs.ch)

Description of the HBG time code
{{Time measurement and standards Time signal radio stations Defunct radio stations Defunct mass media in Switzerland