OMA was the callsign of a Czech
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, a ...
station. The station was operated by the
Astronomical Institute of Prague and the transmitters were located at
RKS Liblice 1
RKS Liblice 1 was a facility for commercial long wave radio transmission located in the Czech Republic about east of Prague near Liblice. It used a T-antenna hung on two tall insulated towers built of lattice steel. The towers were demolished by ...
.
The station transmitted in the
LF band on 50 kHz with a power of 7 kW and in the
HF band on 2500 kHz with 1 kW.
A reserve LF transmitter was located at
Poděbrady
Poděbrady (; german: Podiebrad) is a spa town in Nymburk District in the Central Bohemian Region of the Czech Republic. It has about 14,000 inhabitants. It lies on the river Elbe. The town centre is well preserved and is protected by law as an u ...
.
OMA, which could be also used for synchronizing
radio controlled clocks, was shut down in 1995.
OMA time signal transmitter was used to synchronize radio clock. The transmit time protocol was changed multiple times. Periodic service maintenance outages lasted for days. The decoding was done in discrete hardware. Commercial use of OMA time signal was limited by absence of highly integrated receiver and decoding chip.
OMA was synchronized by Cesium Reference clock run by CSAV Czech Academy of Sciences, Kobylisy, Prague. Limited series of secondary 5MHz references with thermostat were manufactured by the institute. The secondary reference employed single transistor crystal oscillator with XF filter. The institute was under keen eye of communist party, dictating the R&D direction. They had there their devoted people. TV broadcasting and high reliability services were synchronized from the Cesium Reference. Today (2020) there are calls to resurrect the transmitter for resilience case. Performance of WWV beacon confirms the importance.
References
External links
* http://www.heret.de/funkuhr/liste.htm
* http://adsabs.harvard.edu/abs/1979RaSc...14..681B
* http://home.zcu.cz/~poupa/oma50.html
* http://www.cl.cam.ac.uk/~mgk25/time/lf-clocks/
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Time signal radio stations