This is only a preview of the December 2020 issue of Practical Electronics. You can view 0 of the 72 pages in the full issue. Articles in this series:
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Triumph or
travesty?
Techno Talk
Mark Nelson
Spoiler alert: This article revolves around a minor news story published in late September this year. Even
then, it was not headline news, and was soon forgotten. It does, however, involve practical electronics,
with implications that are broader than you might imagine, calling into question the competence of
Britain’s leading broadband infrastructure provider. Am I over-reacting? Read on and see what you think.
O
ne of the first things that
reporters and media relations
people are taught during training
is that today’s news stories will be wrapping fish suppers tomorrow. Old news
is soon forgotten, and for people and organisations castigated in those stories,
this is no bad thing if unwelcome news
can be buried rapidly. Another lesson
taught early on is that when you’re in a
hole, you stop digging. And you certainly don’t shout about your predicament.
Despite these truisms, on 22 September,
BT Openreach’s press office announced
that its most experienced engineers had
taken 18 months to solve a mystery fault
that had plagued the broadband connections of residents living in a rural village
in mid-Wales. Openreach gushed: ‘For
months the inhabitants of Aberhosan
– along with some neighbouring communities – have endured poor broadband
connectivity and slow speeds every morning at 7am, despite repeated visits by
engineers to fix the fault. Frequent tests
proved that the network was working
fine and local engineers even replaced
large sections of cable that served the village, but the problems remained.’ – see:
http://bit.ly/pe-dec20-open
World-class service in action?
Excuse me, is Openreach – which boasts
on its website of providing world-class
customer service – really unable to clear
a fault in under 18 months? Evidently
so. Yet, the company’s website also declares, ‘Data is such an essential part
of consumers’ lives they have high expectations when it comes to service. To
make sure Openreach can meet them,
we have quality of service standards –
values we measure ourselves against to
track how we’re performing.’ That the
company considers taking 18 months
to clear a fault as a matter for self-congratulation strikes me as, well, risible.
After studying 20 different reports
on this farrago, I can only say that not
one of them stacks up. The Openreach
version simply spouts waffle about a
maladjusted television receiver without explaining how a short burst of
10
electrical interference can block ADSL
broadband service throughout a whole
village as well as at properties outside
the village. The broadband technology in use must be pretty feeble if is
so poorly shielded against a burst of
interference. Of course, none of the
media reports describes how long the
trouble persisted each day. Given that
the problem recurred every day at the
same time, presumably the outage was
only temporary and cleared itself rapidly, in good time for the same problem
to recur the next day.
Mains-borne interference?
Openreach finally traced the source of
the interference to an ‘old’ television
receiver, but given that mid-Wales was
converted from analogue to digital television in 2010, the oldest tellies in use
there cannot be more than ten years old.
So how can an ancient TV still be in use
if it’s an old analogue UHF set (unless the
viewer is using a Freeview box to convert digital to analogue). In that unlikely
case, it is indeed possible that the television’s power supply might have caused
mains-borne interference from the TV’s
power supply. The Philips G8 model of
the 1970s, for example, was notorious for
radiating nasty 25Hz ‘hash’ over wide
areas. But are we really suggesting that
this noisy telly was adjacent to the village distribution cabinet and was fed
from the same supply feed and phase?
If so, perhaps Openreach should fit better mains filtering on incoming mains
feeds – and provide earthed screening
inside their cabinets.
In any case, as a forum poster at Digital
Spy (http://bit.ly/pe-dec20-dspy) points
out, Openreach could have looked at
the DSLAM logs, to see exactly when
the lines were affected with loss of (or
reduced) sync. The same thread states
that ITV Evening News had interviewed
villagers who said their broadband was
still misbehaving – and that if anything,
it had actually got worse! One of them
added that the outage occurred even
when the owners of the unruly telly
were away on holiday – spooky or what?!
Precise explanation
Openreach identified the fault as ‘a
phenomenon known as SHINE (single
high-level impulse noise) where electrical interference is omitted from an
appliance that can then have an impact
on broadband connectivity’. Someone
at Openreach clearly doesn’t know the
precise difference between ‘omitted’
and ‘emitted’! The Zen Internet website
explains more precisely that SHINE occurs when interference is generated as
a burst – for example, when a device
is powered on or off. As a result, disconnections or line errors may result at
the time a device is switched on or off.
Incidentally, there is another kind of
interference affecting broadband called
REIN (repetitive electrical impulse
noise), which, as the name suggests,
occurs persistently. This will typically
result in disconnections or line errors
while the interfering electrical device
is in use and at worst, may prevent any
connection being established at all. In
either case, come REIN or come SHINE,
broadband users are likely to see persistently slower data speeds while the
automated systems work to mitigate
the interference by throttling back the
maximum connection speed.
Good news and bad
The best comment was on the Hackaday.
com website: ‘We’ll say one thing for the
good people of Aberhosan: they must
be patient in the extreme to put up with
daily Internet outages for 18 months.’
And as a reward, Aberhosan residents
will soon be connected to fibre, as part
of Openreach’s work with the Welsh
Government to further expand the fibre broadband network in rural Wales.
Meanwhile, in other news the UK is
now among the slowest countries in
Europe for broadband download speeds.
Analysis and advice organisation www.
cable.co.uk reports that with an average (mean) broadband download speed
of 37.82Mbit/s, the UK comes 22nd out
of 29 western European countries. In
global terms the UK comes 47th, against
34th last year. Nothing to be proud of.
Practical Electronics | December | 2020
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