4G phones disrupt cable television

The next generation of mobile phones disrupt cable television according to an official report, but the communications watchdog is confident the issue will be resolved before they go on sale.

Ofcom has been aware that Long Term Evolution – or 4G – mobile phones caused interference to cable TV set-top boxes and called in Cobham Technical Services to investigate last year.

The technical consultancy's report was presented to the communications watchdog in December, and revealed that of the nine boxes tested, seven suffered interference from 4G devices used up to a metre away. Graham Louth, spectrum policy director at Ofcom, said: "We will be keeping a close watch on the issue." He added that following the results of the report: "We are less concerned than we were before."

The regulator said there was still plenty of time for set-top box designers to deal with the issue as 4G devices, offering internet browsing speeds of up to 20 times quicker than current mobile phones, will not be introduced until 2013 at the earliest.

The operators will offer the new phones after the auctioning of spectrum – the valuable 800Mhz band – freed up by the digital TV switchover next year.

Yet, the phones will use the same frequency as the cable set-top boxes and, as the testing found, can disrupt the majority of the current generation.

Issues include a break-up of the signal, a loss of synchronisation between the images and sound to a total loss of picture.