Sennheiser’s Hillbich ponders spectrum issues

Italian magazine Backstage (Tecniche Nuove Editor, Milano) is publishing this month a long and interesting interview with Norbert Hilbich of Sennheiser Electronics, writes SVG Europe Italian Correspondent, Roberto Landini. His replies are concerned with European digital television and potential issues arising around radio-microphones and wireless devices in general. What follows is a kindly granted brief excerpt of that interview.

The starting point is the saturation of the radio spectrum especially in urban centres, where the wireless environment is pretty packed. This makes it difficult to find remaining gaps in the spectrum for high quality interference free productions of content for TV shows, etc (though the European landscape is rather different and in some countries certain spectrum can be gained by the digitalization of the terrestrial TV production and other services).

But the desired gain of the spectrum is not always given as with the digitalization more programmes went on air. Besides that the introduction of HDTV needs more capacity again. Large scale events, such like all kind national and international sport events need already a frequency coordinator to find reliable gaps for interference free productions.

The sell of the Digital Dividend (spectrum 790 – 862MHz) to other users will make it more difficult for high quality interference free productions in the remaining spectrum 470 – 790MHz which is shared with terrestrial TV distribution. These other users do not allow the parallel use of their spectrum (790 – 862MHz) with wireless microphones.

Sennheiser products and some of the competitors as well have frequency scanning facilities integrated in their products. These will allow finding free gaps in the spectrum to operate the wireless links. This can be used for single wireless links and also for small size multichannel set-up.

The study of the German Network Agency has shown that wireless mics and in-ear monitor systems need for the daily productions in a centre like Berlin about 100MHz of free spectrum. This spectrum is for daily productions that happen everyday everywhere.

Special events need more usable spectrum: sports championships, Olympic games, international soccer competitions, international political meetings etc. These events of national interest take almost any free space for the operation of wireless mics.

The difference in the frequency use between the US and Europe in general has historical/political reasons – the spectrum has a different organisation, but similar set- up due to physical reasons like wave propagation etc.

In Europe a certain harmonisation can be seen despite the fact there are still various national differences. The European government is the driving force behind a general harmonisation within the European Community and tries to coordinate future activities. Background of the coordination is easier cross border operation of several services as well as the economies of scale.

In Italy though some products by Sennheiser can simply be used, since the National Plan for Frequency Division is assigning the spectrum from 1785 to 1800MHz to the Ministry of Defence for their fixed and mobile communication services. So, not all wireless device available throughout Europe will be usable in Italy because of this stringent limitation.

Therefore the Italian Sennheiser distributor Exhibo SpA has officially issued a note which specifies some of the products launched at ProLight+Sound 2011 will not be distributed on the Italian territory, nor any evolution series radio-mic operating on frequencies between 1785 to 1800Mhhz will be accepted in the service dep because its use is against Italian law.

Such is the lot of the radio mic manufacturer in Europe…

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