Poříčany

Klučov is a municipality and village in Kolín District in the Central Bohemian Region of the Czech Republic. It has about 1,100 inhabitants.

Chrást (until 1947 Manderšejd-Chrást; German: Manderscheid-Chrast) is a municipality and village in Nymburk District in the Central Bohemian Region of the Czech Republic. It has about 500 inhabitants.

Hořany is a municipality and village in Nymburk District in the Central Bohemian Region of the Czech Republic. It has about 200 inhabitants.

Velenka is a municipality and village in Nymburk District in the Central Bohemian Region of the Czech Republic. It has about 300 inhabitants.

Třebestovice is a municipality and village in Nymburk District in the Central Bohemian Region of the Czech Republic. It has about 1,300 inhabitants.

Chrášťany is a municipality and village in Kolín District in the Central Bohemian Region of the Czech Republic. It has about 700 inhabitants.

Liblice (German: Liblitz) is a village and administrative part of Český Brod in the Central Bohemian Region of the Czech Republic. It has a population of 837 (2011).

The RKS Liblice 2 are two 355 m (1,165 ft) tall guyed masts located east of Prague near Liblice, in close proximity of the RKS Liblice 1. These lattice steel towers are built 120 m (390 ft) apart from each other, what formed a slightly directional radiation pattern directed towards Spanish Madrid transmitter on the same frequency. The masts carry a special anti-fading cage aerials. Designed by Jan Šťovíček, these supertall towers currently stand as the tallest towers in the world used for broadcasting in the medium-wave range. RKS Liblice-2 was built in 1976, and is used for broadcasting on 639 kHz, with a period of inactivity from January 2022 to September 2023. During construction, two new transmitter devices of the type Tesla SRV 750 with an output power of 750 kW were installed. At first, these transmitters were switched in parallel for a transmission power of 1500 kW, after 1990 only 750 kW was used for broadcasting. Since 2023, the transmitter broadcasts with only 20 kW of power, a significant lowering. The old transmitter device was replaced with a semiconductor type TRAM one.

RKS Liblice 1 was a facility for commercial long wave radio transmission located in the Czech Republic about 33 km (21 mi) east of Prague near Liblice. It used a T-antenna hung on two 150 m (492 ft) tall insulated towers built of lattice steel. The towers were demolished by explosives on August 11, 2004, as they were no longer needed. The time-signal broadcasts on VLF ceased in 1995 and the medium-wave broadcast of Czech Radio Programme 2 was transferred to the adjacent site with a super-power transmitter, Liblice II.

OMA was the callsign of a Czech time signal station. The station was operated by the Astronomical Institute of Prague and the transmitters were located at RKS Liblice 1. 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. 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.