PLAN TO JAM MOBILE PHONES IN SCHOOLS IS
MADNESS
By Lewin Day
March 24th, 2023.
Mobile phones in schools. If you’re a teacher, school staffer, or a parent,
you’ve likely got six hundred opinions about this very topic, and you will
have had six hundred arguments about it this week. In Australia, push has
come to shove, and several states have banned the use of mobile phones
during school hours entirely. Others are contemplating doing the same.
In the state of New South Wales, the current opposition party has made it
clear it will implement a ban if elected. Wildly, the party wants to use mobile
phone jamming technology to enforce this ban whether students intend to
comply or not. Let’s take a look at how jammers work in theory, and explore
why using them in schools would be madness in practice.
CELLULAR JAMMING 101
In general, mobile phone jammers work in a relatively simple fashion. They
simply random noise broadcast radio frequency signals on the same
frequencies used by cellular networks. If the signal from the jammer is
powerful enough, it will drown out the signals from cellular base stations,
and stop phones from making contact with the network. Typically,
broadcasting noise at high power across cell phone channels is all that’s
required to successfully jam all communication.
Depending on the amount of power you put out, and the antennas you use,
you can vary the area affected by your jammer. Of course, measuring this
area is an inexact science. In much the same way you can’t stop your
home WiFi network from reaching outside the front gate, you can’t readily
limit a cell phone jammer’s output to, say, the boundary of a schoolyard.
And therein lies the problem with using cellphone jammers in schools.
Given that most schools are in built-up areas, there is a high likelihood of
jammers spilling over to mobile phone users in surrounding homes and
businesses. The outcomes would be profoundly negative in all cases. At
best, residents and workers would be deprived of access to connectivity
they need to do their jobs and pursue their very lives. At worst, emergency
calls could fail to connect, and lives could be put on the line.
It’s for this reason that cellphone jamming is very much illegal in Australia,
and most everywhere else for that matter. It doesn’t matter whether you
want to jam signals in your own home or business, or just have a jammer in
your pocket to keep your devices in the dark on the go. Owning, using, or
supplying a jammer is illegal in Australia. It’s thanks to a permanent ban put
in place by the Australian Communications and Media Authority.
Interestingly, though, there is a limited exception to the permanent ban, and
there has already been a live trial jamming technology within the state of
NSW. Via a special exception granted by the ACMA, the government has
implemented mobile phone jammers in the Lithgow and Goulburn
Correctional Centers. Since mobile phones may enter a prison as
contraband, the jammers act as an extra measure to help prevent their use.
The jammers were first trialled in Lithgow beginning in 2013. The trial
aimed to determine whether the jammers would unduly interfere with
regular mobile phone users outside the jail. After the trial proved
successful, an ongoing authorization was granted in 2018. A trial at
Goulburn Correctional Center is ongoing. In this case, the Goulburn facility
exists in a more populated area, and thus there is a greater risk of the
jammers causing problems for surrounding residents. As per requirements
of the ACMA, the devices used in Goulburn may not cause radio emissions
above -128.5 dBm/kHz outside the prison facility. The intention of this
measure is to make sure legitimate phone users outside the prison are not
affected by the jammer.
IT’S PROBLEMS ALL THE WAY DOWN
While the authorities have largely supported the use of jammers in prisons,
schools are another thing entirely. Jammers would affect students,
teachers, and staff alike. They would also affect parents at school drop off,
and any contractors working in or delivering to the school. Few of these
people would expect to be cut off from their phone service, but jammers
don’t discriminate.
The blanket use of jammers in schools would thus present concerning
safety issues. Any emergency calls would have to be made via landline.
This could introduce great delays if somebody is injured out on a
playground, on the outskirts of the school, or in a building without a phone
line. Indeed, schools these days have far fewer landline phones due to the
rise of the mobile phone. Plus, these are not accessible to students or
visitors, either. It would be a tragedy for a student to suffer a medical
emergency and not have help arrive in time because a jammer was
blocking calls.
There are issues with the realities of jamming capability, too. Strong
jamming will leak beyond school grounds and cause condemnation from
surrounding residents. Meanwhile, if jamming is done conservatively, the
jammers may not be effective at their job. Industrious teens with
smartphones would readily find any jamming blackspots within days. In
fact, you could likely map areas where jamming had failed by taking a
drone up and plotting out clusters of disaffected teenagers.
WAIT, WHAT?
Curiously, there has been little talk of the specifics of the policy. However,
one thing stands out: there has been talk of a proposal by a company
referred to as “Educell” which has no visible online presence we could find.
Speaking to media, NSW Labor Party leader Chris Minns also hinted that
emerging technology could block students from making calls, texting, and
using the internet, while allowing emergency access to those with medical
conditions. If that is the case, that would require some kind of advanced
cellular device within the school itself. It would have to force student
phones across all networks to connect to it in place of existing conventional
cell sites. Only then could it allow emergency calls while blocking other
uses.
It seems unlikely such a device could fit within any school budget, nor gain
the approval of network carriers to effectively pull a man-in-the-middle
attack on their subscribers. It would also require a continually-updated
white list to allow staff to use their devices while blocking those of students.
Any visitors to the school would also be subject to blocking unless they had
their number whitelisted as well. Alternatively, such a system could operate
on a blacklist method, but then students could simply buy a new SIM card
or provide the school with a fake number to avoid being subject to the
restrictions.
Neither Hackaday nor the ACMA has seen detailed technical specifications
on Educell’s tools. One suspects such flexible phone banning tools are
more of a nice-to-have idea, rather than something that is readily practical
with solutions available on the market.
REALITY CHECK
In reality, the schools of NSW could instead follow the example of those in
other states. Teachers have simply used their disciplinary authority to
punish students for using their phones in class. Other schools have
mandated that they remain in lockers during school hours, or in special
Faraday cage-like pouches to ensure they’re non-operable. All these
measures are far cheaper and simpler than implementing jammers. They
also have zero effect on the surrounding community. Plus, they don’t stop
staff, parents, and visitors from using their own phones for work purposes
or in an emergency situation.
The proposal has quickly led to wild headlines comparing the treatment of
students to prisoners. That, combined with the technical infeasibility of the
proposal, may lead to this jammer policy getting quietly dropped for a more
conventional ban on phones in schools. If not, though, expect the road
towards school-based cell jamming to be a bumpy and uncomfortable one
for everybody involved.
Link to article https://hackaday.com/2023/03/24/plan-to-jam-mobile-phones-in-schools-ismadness/