Power reductions like this are mostly due to a very old transmitter. There are still several dozen >> 100 kw MW transmitters in service that date from the 1950's or 1960's. Most of these transmitters never achieved more than 50% efficiency.
With the introduction of PDM and PSM, and the scheme Thales uses (PDM + PSM), for digital modulation of analogue AM, 80% efficiency is typical for these transmitter's efficiencies. [THIS POWER DROP SCHEME DOES NOT WORK WITH SHORTWAVE!] When there is an upgrade to digital modulation schemes -- the output power can be cut by 50%. Hungary did this with one of its national network transmitters 3 or 4 years ago. Also, usage of OPTIMOD [and general optimization of the entire antenna system] and audio chain can make the 50% power cut work -- and actually become an improvement. If it were not for the noise that exists in the shortwave band in the US, Western Europe, select cities in North Asia (and a few in South Asia) -- there would be no need FOR SW TRANSMITTERS BEYOND 100 kw! RNZI is proof of this -- if there is any need for further proof. Max Power Subject: [HCDX] MW: Nitra, Slovakia 1098 kHz - power reduction > Hi, there is a significant power reduction at Nitra transmitter of Slovensky Rozhlas > (Slovakia) on 1098 kHz. > > History of Nitra / Velke Zaluzie transmitter: > > - formerly it had 1500 kW (750+750) > - some time ago the power has been reduced to 260 kW > - now the Nitra / Velke Zaluzie transmitter has been switched off and the modulation > moved to Nitra / Jarok transmitter which has only 50 kW > > So now the data are as follows: > > 1098 kHz SVK Nitra / Jarok 50 kW 24h > > > Karel Honzik > the Czech Republic (Czechia) ---[Start Commercial]--------------------- World Radio TV Handbook 2003 is out! Order it now! http://www.amazon.com/exec/obidos/ASIN/0823059677/hardcoredxcom ---[End Commercial]----------------------- ________________________________________ Hard-Core-DX mailing list [EMAIL PROTECTED] http://dallas.hard-core-dx.com/mailman/listinfo/hard-core-dx http://www.hard-core-dx.com/ _______________________________________________ THE INFORMATION IN THIS ARTICLE IS FREE. It may be copied, distributed and/or modified under the conditions set down in the Design Science License published by Michael Stutz at http://dsl.org/copyleft/dsl.txt
