Freeview telly test suggests 4G interference may not be a big deal

A trial 4G network, covering 22,000 homes just left of Birmingham, only interfered with TV reception in 15 of them - paving the way for an interference-free rollout over the summer, we're told.

The trial was conducted by at800, the organisation charged with spending £180m of cell network operator money to solve the problem. At800 wrote to all 22,000 homes asking them to watch for changes, and received 100 calls of which 15 could be attributed to 4G signals, and all those were fixed with a cheap filter.

That's great news for the operators, who'll get a refund if the £180m isn't spent, but more importantly won't be pressured into putting better filters on their base stations (which are expensive) and won't have to face any backlash from taking Eastenders off the air.

Original predictions were that two million homes could be affected, while the latest modelling put the number at three quarters of a million facing reduced reception and 30,000 left staring at blank screens. Those numbers should have seen 120 homes with problems during the trial, rather than fifteen.

No one knows how serious the problem will ultimately prove to be, as in most instances (including all fifteen discovered during the trial) the problem is a signal booster feeding the telly which amplifies across the TV band, including the bands where TV used to be and 4G intends to be. Such boosters were fitted by home owners, or landlords, so no-one knows how widespread they are or how many homes will be able to fit their own filters.

The filters are cheap, but have to be plugged in between the aerial and the booster which is fine if the booster is near the back of the TV, but a right pain if it's in the loft or atop a tower block etc. Some boosters are also built into portable aerials, making it difficult to fit a filter. Given that no-one knows how many boosters there are and of what kinds, let alone where they're fitted, the scale of the problem has been hard to judge.

If this trial is indicative of the whole country then the problem is smaller than anticipated and operators can start building out 4G networks with alacrity. Bigger trials will be needed, and problems will no doubt emerge, but for the moment it's good news all round. ®