Four years ago, newspaper headlines were awash with stories that 4G mobile phones would wipe out Freeview reception.
Tabloids foamed with rage at the possibility of millions losing reception of Coronation Street or X Factor, caused by the introduction of new 4G/LTE mobile services in the frequency band right next to digital terrestrial TV. Householders would be forced to install filters (pictured above) in order to keep watching TV.
So what's the current state of affairs? Are many households really affected by 4G interference?
Officially, there's been just over 14,000 confirmed cases of interference so far as a result of mobile services in the 800MHz frequency band. That's according to official minutes from the 4G/TV Co-existence Oversight Board to Government Ministers. The Board comprises of representatives from broadcasters, mobile network operators and observers from organisations including Ofcom and DMSL - the company that operates at800 - who is responsible for informing households about possible interference and for fixing Freeview reception.
Official statistics confirm there's an average of 1.46 confirmed cases of 4G interference from each mast, but with wide individual fluctuations:
An interference hotspot was identified in the Alcester area (near Stratford-upon-Avon) around Easter. Since the activation of a 4G mast at 800 MHz in mid-March, and up to the start of April at800 received calls from 72 households and visited 46 confirming 43 cases of 4G interference, well above the average experience.
Across the UK, in March 2016, at800 was contacted by a total of 3,379 households reporting interference that at800 believed could be caused by 4G. Engineers visited 1,475 properties, and filters were sent to a further 1,904. Of the 1,475 viewers to whom at800 sent engineers, 621 were confirmed as being impacted by 4G.
In the three months to the end of March 2016, of the households to whom engineers were dispatched, 1,958 cases of 4G interference were confirmed, up from 1,290 during the same three month period a year earlier. Importantly, the figures for confirmed 4G interference only cover households engineers were sent to. 4G filters have been sent out to far more households.
While householders should receive a postcard from at800, alerting them to the potential for interference, evidence shows that some householders who have been confirmed as suffering from 4G interference were not sent a postcard. A new database covering new homes, which have been particularly affected by these omissions has now been installed by at800.
Audits covering January - March 2016 confirm that a small number of errors are being made by engineers: there were 11 cases overturned: 9 from 4G to non-4G and 2 from non-4G to confirmed 4G. Of the 9 4G to non-4G overturns, 7 cases were attributed to a faulty or misconfigured spectrum analyser that generated incorrect signal readings resulting in misdiagnosis of 4G interference and the remaining 2 overturns were due to the engineer not accounting for poor quality RF connections, which were replaced at audit thereby resolving the issue; the 2 non-4G to 4G overturns were because remedial work to existing aerial installations and retuning meant that the potential for the contribution of detected 4G signals to the interference was not taken into account.
During the last twelve months, mobile operator Three has started to aggressively roll-out its 4G/LTE network in the 800MHz band. Crucially, it holds the right to 4G spectrum closest to existing Freeview services. O2 and Vodafone, the first to widely roll-out 4G in the 800MHz band use frequencies slightly further away, but can still cause some interference. EE had already established an extensive 4G network using frequencies that don't interfere with Freeview, but EE has recently also signalled a move in to the 800MHz band. As a result, interference to Freeview can begin to happen, even in areas where 4G mobile signals have been available for a while.
In short, there's no-where near the national blackout you may have read about in the newspapers. But interference is happening - annoying enough if you are among those affected. Mobile networks look set to continue to affect Freeview reception for many more years to come: 5G and the transfer of another chunk of frequencies currently used by Freeview looks set to create more issues down the line...
- Viewers who think they may have a problem with Freeview as a result of 4G roll-out can contact at800, by visiting www.at800.tv, or calling 0808 13 13 800, Monday-Saturday 08:00-18:00. Calls are free from UK landlines and mobiles.