There are dozens of pockets across the city where people have frequent mobile service failure and calls dropping out – and the bars on their phones could be lying to them. Here’s why.
There are dozens of pockets across the city where people have frequent mobile service failure and calls dropping out – and the bars on their phones could be lying to them. Here’s why.
Rebekah Higgins moved into her new home on Brisbane’s southside eight years ago only to discover she couldn’t make a call or send a text message on her mobile phone.
“I get almost no reception in my house at all,” she says.
Higgins is among thousands of Brisbane residents who struggle to get reliable 5G reception at their home, workplace or local supermarket.
“All my family knows to only call me via Facebook,” she says.
A national audit of mobile phone coverage is under way. There are dozens of pockets across the city where coverage is “modest” – defined by frequent service failure, calls drops and noticeable distortion.
The major telcos, including Optus and Telstra, have their own coverage maps but they do not always reflect their customers’ on-the-ground experiences, which are being collated for the federal government by consultancy firm Accenture.
Advertisement
To make a frustrating situation even more so for Higgins, a mobile phone tower is less than two kilometres from her home.
That might be the source of the problem, says Associate Professor Dhammika Jayalath from the Queensland University of Technology.
He says despite proximity to a tower, issues such as vegetation or “under-tower shadow” – a phenomenon where actually being too close to the tower – can weaken a signal.
Suburbs with 5G struggles
George Bourne lives in Mackenzie, in Brisbane’s south-east. The 58-year-old’s reception is so poor, he resorts to walking out to the footpath, or onto his back deck, to make a call. “Whether it helps or not, I’m not sure,” he says.
The audit data shows customers with Optus, Telstra and TPG struggle to receive good coverage in a cluster of streets in the suburb, off Mount Gravatt Capalaba Road.
“It really is hit and miss,” Bourne says. “It seems like it depends on whether the wind is blowing in a particular direction because it’s that unpredictable.”
Advertisement
His adult daughter has given up trying to use her phone at home. “She just uses Messenger,” he says.
One provider gave him a Femtocell booster, a device that plugs into the wall to boost signal quality.
“It didn’t work,” he says. “We’re in suburbia with new developments and townhouses going in all around us. We’re in a two-storey house and we’re elevated too – it’s not like we’re in a gully.”
The audit shows Optus customers struggle with 5G reception in pockets of Manly West, Wynnum West, Jamboree Heights, Jindalee, Graceville, Bardon, Corinda, Lutwyche, Wavell Heights, Chermside, Kalinga and in the streets around the Enoggera Barracks.
According to the data, Telstra has modest 5G coverage in parts of Holland Park, Seven Hills, Wynnum West, Rochedale South, Kuraby, Stretton, Eight Mile Plains, Tarragindi, Fig Tree Pocket, Alexandra Hills, Bridgeman Downs, Chermside, Albany Creek and Nudgee.
Advertisement
Customers of both Optus and Telstra struggle with lower-quality coverage in areas of Carindale and Pallara, according to the audit.
As for testing a phone signal, reception bars on mobile phones should be viewed with scepticism. To get a proper reading, you need to access Field Test Mode, which is accessible via settings on an Android or by calling *3001#12345#* on an iPhone.
That will give you a reading of signal strength in decibels, under the RSRP [Reference Signal Received Power] or RSRQ [Reference Signal Received Quality] measures. The closer to zero, the better your signal.
For RSRP, anything between 0 and -115 decibels (dBm) is regarded as good coverage, according to Accenture’s metrics, while anything below -115 will begin to cause trouble. For RSRQ, anything between 0 and -15 dBm is decent, while a signal heading towards -20 is getting patchy.
What dictates whether you have good signal?
How is it that we can beam a high-definition cat video into deep space, but a phone call can barely survive a trip in an elevator, and it’s often a battle to load Instagram on the train?
Advertisement
Where you are in relation to mobile cell towers is a factor. Towers also aim signals towards urban centres and roads, so even if you’re close to one, it might be beaming its signal in the opposite direction.
The geographical area covered by a base station is called a “cell”, and these cells create a patchwork of reception. Antennas and booster cells attached to skyscrapers, power poles and bus stops help amplify the signal through built-up urban areas.
But many things can disrupt a wave carrying your phone call or YouTube video, including buildings, trees and hills. Even dust and water in the air can create problems.
“If you talk to people up in the north – Darwin, Cairns – during the monsoon, every afternoon when it starts pouring with rain, mobile signal in most areas will drop out,” says Associate Professor Mark Gregory, a telecommunications expert at RMIT.
Wood, glass and concrete will also degrade a signal, so if you’re inside a building your signal has to work harder.
But metal is the worst offender. Houses with metal roofs often require mobile boosters to funnel a signal inside.
A solid or mesh enclosure of metal – called a Faraday cage – disrupts radio waves because metal, as a conductor with free-flowing electrons, interferes with electromagnetic radiation.
Advertisement
That’s why your signal cuts off when the doors of an elevator close. A train is also essentially a metal cylinder and even metallic tints on the windows can deflect signals.
Similar problems can occur in supermarkets or shopping centres, with cars parked on the rooftop.
Jayalath explains that 5G uses much higher frequency than 4G, and the now-defunct 3G.
But it struggles more to transmit through thick walls and vegetation.
That may be the case around George Bourne’s home in Mackenzie. The closest cell tower that services three major phone providers, Optus, Telstra and Vodafone, is on the opposite side of the Gateway Motorway.
However, the motorway might not be the issue.
“There’s a big wall of trees facing the road,” Jayalath says. “That would create some signal degradation.”
The booster Bourne was given would not have worked because “boosters are best used to extend the range of an existing good signal, not to strengthen a poor signal,” Jayalath says.
Higgins’ Mount Gravatt home is close to two Optus cell towers, one on Logan Road and another near Nursery Road.
Jayalath explains dead zones can be created by “under-tower shadows”, although he stresses not all phone users will have problems.
“It’s like shining a light from a torch. Just under your cell tower you may not get good reception,” he says.
“An under-tower shadow depends on the height of the cell tower, the frequency used and the antenna configuration.”
Telstra concedes its customers in a pocket of Holland Park on Brisbane’s southside struggle with 5G reception and it has “plans in the pipeline to improve the capacity and performance of our existing coverage”.
“Finding an appropriate spot for a new mobile tower in urban areas can sometimes be a challenge though,” a Telstra spokesman says.
“For example, we’ve made several attempts over a number of years to acquire sites for new towers in places like Chermside and Alexandra Hills.
“We also work with shopping centres to discuss options to improve coverage inside their buildings.”
Telstra says residents could improve their mobile coverage by using their NBN connection to access Wi-Fi calling. “This is a free setting on most popular mobile phones and allows your mobile to use a Wi-Fi network to make and receive mobile calls,” their spokesman says.
An Optus spokesman said: “If a customer is having an issue with a specific location, such as a suburban area of Brisbane, or inside a supermarket, for example, we can investigate on their behalf.”
Start the day with a summary of the day’s most important and interesting stories, analysis and insights. Sign up for our Morning Edition newsletter.