Paul VK2ICQ adds:

Thanks to Stuart VK2FSTU for the link.  Note that we’ve previously posted a video on this exact event by Tom Scott, if you missed it first time around and you’d prefer to watch rather than read, here it is again!

From Hackaday, written by Richard Baguley, original post here.

The place is the historic lecture theater of the Royal Institution in London.  The date is the 4th of June 1903, and the inventor, Guglielmo Marconi, is about to demonstrate his new wireless system, which he claims can securely send messages over a long distance, without interference by tuning the signal.

The inventor himself was over 300 miles away in Cornwall, preparing to send the messages to his colleague Professor Fleming in the theater.  Towards the end of Professor Flemings lecture, the receiver sparks into life, and the morse code printer started printing out one word repeatedly: “Rats”. It then spelled out an insulting limerick: “There was a young man from Italy, who diddled the public quite prettily”.  Marconi’s supposedly secure system had been hacked.

The person behind this hack was Nevil Maskelyne, an inventor, magician, and general troublemaker who was a long-time rival of Marconi.  He was the manager of a rival wireless company and had been involved in a number of disputes with Marconi over the patents that covered wireless telegraphy systems.  He decided that the most effective way to show that Marconi’s claims were hollow was a practical demonstration.

In the trade journal The Electrician (the Hackaday of its time) he detailed how he hacked the system. One of the fundamental claims of Marconi was that because his system used a tuned signal, other signals would not interfere unless they were tuned to the same frequency.  This, however, had not been proven to the satisfaction of Maskelyne, and he didn’t accept that the system was really secure.  So, he set out to demonstrate this.  But how could you prove this?  In his account in The Electrican, he wrote that:

“When, however, it was pointed out to me that the practical demonstrations accompanying the lecture rendered independent tests possible, I at once grasped the fact that the opportunity was too good to be missed…  The only hope, then, was to interpolate messages calculated to anger and “draw” somebody at the receiving end.  If that could be done, there would be proof positive.”

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Via Stuart VK2FSTU, who adds:

Perhaps this is a way we could think beside JOTA of gaining more young bods into Amateur Radio ranks?  Bears thinking more about me thinks.

The RSGB Youth Committee is delighted to announce that the bid to host the IARU Youngsters on the Air (YOTA) 2017 summer camp was successful.

We are proud to be hosting this prestigious international event at Gilwell Park, the UK Scouting HQ, from 5-12 August 2017.

What is it?

It’s a fantastic chance for young people to build relationships with like-minded people from other countries and develop international friendships through amateur radio.

Around 100 young people under the age of 26 from all over IARU Region 1 will come to the UK to take part.

There will be a week-long range of wireless technology activities including a special event station, a buildathon, antenna building, an Amateur Radio Direction Finding (ARDF) contest and a Summits on the Air (SOTA) activation.

There will also be an opportunity to visit Bletchley Park—including the National Radio Centre—and the Science Museum, and to take part in some other non-radio activities such as kayaking, raft building and assault courses.

From Fastcompany.com, original post here.  Written by Sean Captain, 23/8/16.

Tech lets wireless access points cancel out interference, providing a speed boost for crowded venues. It might help cellphone towers, too.

Look at the night sky on a camping trip and the stars are everywhere.  Look from a city full of lights and you barely see any.  The disappointment is similar when you go from a Wi-Fi network in isolation to one crowded with dozens, maybe hundreds, of other users.  The problem, in both cases, is interference: signals crashing into each other.  Adding more Wi-Fi access points, or APs, to extend the coverage area can cause more collisions, since they are all fighting over the same limited spectrum.

Now MIT researchers say they’ve found a fix: getting APs to anticipate how they will collide and tweak the signals to undo the damage.  In today’s world of busy Wi-Fi networks, the way to avoid a crash is to take turns, like cars meeting at a four-way stop sign.

“If you’re the only person, you get to send [data] all the time,” says Hariharan Rahul, a visiting researcher at MIT’s Computer Science and Artificial Intelligence Lab.  “If there are two people you get to send … about half the time.  As there are more and more people, you get less and less opportunities to send.”

Rahul worked with two PhD students and professor Dina Katabi on a new solution: Instead of avoiding collisions, take advantage of them.

Now get ready for the jargon salad.  The technology MIT developed is named MegaMIMO 2.0. (It’s an extension of a technology called MIMO that coordinates multiple antennas inside a single AP.)  It was outlined this week in a paper called “Real-time Distributed MIMO Systems” at the Computing Machinery’s Special Interest Group on Data Communications conference in Brazil.

Wireless Pileup

To understand what happens when radio waves collide, go back to your high school lessons that show them as undulating lines with peaks and valleys.  If two of these lines overlap perfectly, peak-to-peak and valley-to-valley, they boost each other.  If they line up peak-to-valley, they cancel each other out.  Usually, they are at some point in between the two extremes, each warping the other.  The MIT team’s ah-ha moment: If they could anticipate how waves would overlap, they could tweak the signals ahead of time to counteract the warping.  “Now when these modified signals come through the air, they are still going to collide with each other,” says Rahul.  “But after the collision, the signal is now what you want.”

Easier said than done.  In fact, the process requires continuous measurement of the wireless network as it’s disturbed by things like connected laptops and phones moving around or people walking by.  It also requires keeping all the access points in communication to coordinate signal-tweaking efforts.  That rapidly eats up bandwidth until none is left.  “If you are coordinating 16 APs, you would essentially spend all your time exchanging information and never actually have any time to send the data,” says Rahul.  That’s hardly a way to boost performance.

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