Techies at UK ISP Andrews & Arnold have demonstrated that ADSL broadband can work over a wet string.
An inquisitive engineer at the company this week decided to test whether wet string could work in place of twisted-pair copper for an ADSL connection.
Using a two-meter (6ft 7in) length of wet string, the engineer was able to reach a downlink speed of 3.5Mbps, which is slow by today’s standards but way faster than yesteryear’s dial-up internet speeds, albeit over a short distance.
While the test was just a “fun” experiment, the engineer was testing a figure of speech probably only heard among network engineers. As the ISP’s boss explains in a blogpost, one of ADSL’s main qualities is that can adapt to function on a really poor line — so bad that it’s been said it will even work on a bit of wet string.
The ‘fiber’ connection test failed using fresh water, but a second try with salty water did the trick thanks to salt’s better conductive properties.
The ISP techie behind the test described the experiment in a string of tweets yesterday. A pair of two-meter lengths of string were dunked into salty water and then connected side by side between two routers.
Professor Jim Al-Khalili from the University of Surrey’s department of physics explained the science behind the experiment to the BBC.
“Although wet string is clearly not as good a conductor of electricity as copper wire, it’s not really about the flow of current,” he said.
“Here the string is acting as a waveguide to transmit an electromagnetic wave. And because the broadband signal in this case is very high frequency, it doesn’t matter so much what the material is.”
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