TRANSRADIO has accepted this challenge and has modernised the LW transmission station in Donebach (Germany). The modernisation included a DRM installation which completely fulfils the requirements concerning the out-of-band emissions of ETSI EN 302 245-1 and ITU SM.1541. The project TRAM/ P 500L consists of two TRAM 250L (250 kW) transmitters, an equalization network (ENW) and a DRM DMOD2 functioning as a digital exciter for the TRAM 250 transmitters. The TRAM 250 L long wave transmitters are based on a future-oriented solid state transmitter concept offering very high efficiency. An improved version of the field proven TRAM 250L has been installed in Donebach providing significantly reduced out-of-band emissions. An innovative paralleling unit (PU) combines both TRAM 250L transmitters to a carrier power of 500 KW and DRM power of 200kW. Moreover, an equalization network (ENW) was implemented to eliminate the disadvantages of the asymmetrical antenna impedance and to reduce mismatch. This resulted in a reduction of the standing wave ratio from the original VSWR of < 1.9 to a VSWR of <1.05 in a bandwidth of +/-5 kHz around the carrier.
The DRM signal is generated by the DRM DMOD2 exciter. The exciter software possesses an automatic equalization algorithm providing a very precise and fast method for setting up the DRM system to deliver minimum out-of-band emissions. Furthermore, no test signal is required during the alignment procedure. Optimisation can take place even during programme transmission.
Mr. Huber, CEO of TRANSRADIO said:” The successfully completed installation of a cutting edge TRAM/ P 500L system in Donebach is in the meantime TRANSRADIO’s third big DRM LW project. The transmitted DRM signal, with 8 dB mask reserve (see below) is a more than excellent result and reconfirms impressively the leading position of TRANSRADIO”.
Donebach „Riding the Longwaves with DRM“
30 April 2008
Longwave is well known for excellent ground wave coverage hence, offering a stable reception. DRM on LW combines the advantages of digital transmission with very good longwave propagation. On the other hand, narrow band longwave antennas with considerable mismatch even inside the transmission bandwidth are posing a big challenge to the broadcast industry.
TRAM/P 500L in Donebach
LW antenna in Donebach
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A SECURE INVESTMENT INTO THE FUTURE
