Mystery interference on phone signal was resolved by replacing widely used form of computer cable, Irish telecoms watchdog found
Wondering what’s causing your area’s bad mobile reception?
The Irish telecoms regulator now has a new explanation – your computer and television cables.
In its latest report, Comreg revealed that HDMI cables were responsible for mystery interference to an unnamed Irish mobile operator’s network in six closely situated locations.
HDMI cables are typically used to connect DVD players and games consoles to televisions. They are also used to connect computers to monitors.
“The harmful interference was reported by a mobile network operator as affecting six sites in an area of approximately 2km radius,” said the watchdog in its report.
When ComReg visited the physical site, the source of the interference “was not immediately clear” because there was “no offending radio equipment operating on the premises”.
But follow-up visits established that “the interference source was most likely to be the cables that were connecting computers and monitors being used onsite”.
This was confirmed when a computer, monitor and the cabling between them was taken away for forensic analysis.
“The tests confirmed that the DVi/Display port adopter cables were emitting strong RF signals at the affected frequency,” said Comreg’s report.
To fix it, the cables were replaced by an alternative VGA cable with a display port adaptor.
“The conclusion of the investigation illustrated that electronic devices which are connected with HDMI cables can create emissions on 891 MHz that in turn can interfere with to the uplink of a mobile network operating nearby,” Comreg concluded.
However, the regulator has also criticised Irish mobile operators for not doing their part to raise awareness of potential sources of interference and says that if operators can’t be bothered to help, Comreg may not prioritise investigations into operators’ complaints of interference.
“ComReg notes that while it has taken a very proactive approach to preventing illegal mobile phone boosters from entering the market, this has not been reciprocated by the mobile network operators whose networks are adversely affected by these illegal devices,” its report said.
Comreg singled out Vodafone and Eir as being the most neglectful in this regard, adding that Three had done only a bare minimum.
“ComReg notes, with some disappointment, that Eir and Vodafone have not taken any of these steps while Three has taken only steps i and ii,” it said, referring to a number of recommendations Comreg made to the operators on the subject earlier this year.
“This limited activity on the part of the operators would suggest that interference complaints arising from mobile phone boosters are generally of a very low priority for them. Going forward, ComReg will take complainant activity or indifference into account when determining the priority afforded to interference cases generally.”