LTE mobiles may cause cable TV interference

Friday, November 27th, 2009 

In response to reports from Germany and various other European studies, the Radio Communications Agency of the Netherlands (Agentschap Telecom) has conducted a set of initial exploratory tests to see if the use of LTE (Long Term Evolution) mobile devices in the 800MHz band interfere with cable television.

The initial conclusions were that:

  • If an LTE mobile phone with a transmitting power as indicated in the draft EC Decision is used at a distance of 3 m from the television set, interference will be caused to three out of four of the television sets based on a standard configuration.
  • Under the conditions described above, the cable reception of neighbours will be subject to interference in half of all cases due to an LTE application.
  • Additional measures taken on four of the in-house systems (to reduce sensitivity to interference further) went beyond simply using an StAI cable from the subscriber transfer point to the television set. This optimisation resulted in a considerable improvement. However, it was observed that at the frequently occurring LTE bandwidths of 5 MHz to 10 MHz, after optimisation, there is still a 50% probability of interference when a mobile application is used at a distance of 1 m from the television set.
  • The quality of shielding and the connection of the other cables (other than those from the subscriber transfer point to the television) were found in an optimised configuration to influence the in-house system’s sensitivity to interference.

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