Saturday, December 31, 2011

New video from ARRL : The DIY Magic of Amateur Radio

From the ARRL:
ARRL's new video, "The DIY Magic of Amateur Radio," is an 8-minute video that follows some of the innovative, imaginative and fun ways "hams" use radio technology in new and creative ways. The presentation is directed toward the DIY (do it yourself) movement, which is inspiring a new generation of creators, hackers and innovators. The message should be helpful for existing members to shape the ways they understand and talk about ham radio.

Wednesday, December 28, 2011

A gentlemen hacker, circa 1903

From New Scientist:

A century ago, one of the world’s first hackers used Morse code insults to disrupt a public demo of Marconi's wireless telegraph
LATE one June afternoon in 1903 a hush fell across an expectant audience in the Royal Institution's celebrated lecture theatre in London. Before the crowd, the physicist John Ambrose Fleming was adjusting arcane apparatus as he prepared to demonstrate an emerging technological wonder: a long-range wireless communication system developed by his boss, the Italian radio pioneer Guglielmo Marconi. The aim was to showcase publicly for the first time that Morse code messages could be sent wirelessly over long distances. Around 300 miles away, Marconi was preparing to send a signal to London from a clifftop station in Poldhu, Cornwall, UK.
Yet before the demonstration could begin, the apparatus in the lecture theatre began to tap out a message. At first, it spelled out just one word repeated over and over. Then it changed into a facetious poem accusing Marconi of "diddling the public". Their demonstration had been hacked - and this was more than 100 years before the mischief playing out on the internet today. Who was the Royal Institution hacker? How did the cheeky messages get there? And why?
It had all started in 1887 when Heinrich Hertz proved the existence of the electromagnetic waves predicted by James Clerk Maxwell in 1865. Discharging a capacitor into two separated electrodes, Hertz ionised the air in the gap between them, creating a spark. Miraculously, another spark zipped between two electrodes a few metres away: an electromagnetic wave from the first spark had induced a current between the second electrode pair. It meant long and short bursts of energy - "Hertzian waves" - could be broadcast to represent the dots and dashes of Morse code. Wireless telegraphy was born, and Marconi and his company were at the vanguard. Marconi claimed that his wireless messages could be sent privately over great distances. "I can tune my instruments so that no other instrument that is not similarly tuned can tap my messages," Marconi boasted to London's St James Gazette in February 1903.
That things would not go smoothly for Marconi and Fleming at the Royal Institution that day in June was soon apparent. Minutes before Fleming was due to receive Marconi's Morse messages from Cornwall, the hush was broken by a rhythmic ticking noise sputtering from the theatre's brass projection lantern, used to display the lecturer's slides. To the untrained ear, it sounded like a projector on the blink. But Arthur Blok, Fleming's assistant, quickly recognised the tippity-tap of a human hand keying a message in Morse. Someone, Blok reasoned, was beaming powerful wireless pulses into the theatre and they were strong enough to interfere with the projector's electric arc discharge lamp.
Mentally decoding the missive, Blok realised it was spelling one facetious word, over and over: "Rats". A glance at the output of the nearby Morse printer confirmed this. The incoming Morse then got more personal, mocking Marconi: "There was a young fellow of Italy, who diddled the public quite prettily," it trilled. Further rude epithets - apposite lines from Shakespeare - followed.
The stream of invective ceased moments before Marconi's signals from Poldhu arrived. The demo continued, but the damage was done: if somebody could intrude on the wireless frequency in such a way, it was clearly nowhere near as secure as Marconi claimed. And it was likely that they could eavesdrop on supposedly private messages too.
Marconi would have been peeved, to say the least, but he did not respond directly to the insults in public. He had no truck with sceptics and naysayers: "I will not demonstrate to any man who throws doubt upon the system," he said at the time. Fleming, however, fired off a fuming letter to The Times of London. He dubbed the hack "scientific hooliganism", and "an outrage against the traditions of the Royal Institution". He asked the newspaper's readers to help him find the culprit.
He didn't have to wait long. Four days later a gleeful letter confessing to the hack was printed by The Times. The writer justified his actions on the grounds of the security holes it revealed for the public good. Its author was Nevil Maskelyne, a mustachioed 39-year-old British music hall magician. Maskelyne came from an inventive family - his father came up with the coin-activated "spend-a-penny" locks in pay toilets. Maskelyne, however, was more interested in wireless technology, so taught himself the principles. He would use Morse code in "mind-reading" magic tricks to secretly communicate with a stooge. He worked out how to use a spark-gap transmitter to remotely ignite gunpowder. And in 1900, Maskelyne sent wireless messages between a ground station and a balloon 10 miles away. But, as author Sungook Hong relates in the bookWireless, his ambitions were frustrated by Marconi's broad patents, leaving him embittered towards the Italian. Maskelyne would soon find a way to vent his spleen.
Nevil Maskelyne
One of the big losers from Marconi's technology looked likely to be the wired telegraphy industry. Telegraphy companies owned expensive land and sea cable networks, and operated flotillas of ships with expert crews to lay and service their submarine cables. Marconi presented a wireless threat to their wired hegemony, and they were in no mood to roll over.
The Eastern Telegraph Company ran the communications hub of the British Empire from the seaside hamlet of Porthcurno, west Cornwall, where its submarine cables led to Indonesia, India, Africa, South America and Australia. Following Marconi's feat of transatlantic wireless messaging on 12 December 1901, ETC hired Maskelyne to undertake extended spying operations.
Maskelyne built a 50-metre radio mast (the remnants of which still exist) on the cliffs west of Porthcurno to see if he could eavesdrop on messages the Marconi Company was beaming to vessels as part of its highly successful ship-to-shore messaging business. Writing in the journal The Electrician on 7 November 1902, Maskelyne gleefully revealed the lack of security. "I received Marconi messages with a 25-foot collecting circuit [aerial] raised on a scaffold pole. When eventually the mast was erected the problem was not interception but how to deal with the enormous excess of energy."
It wasn't supposed to be this easy. Marconi had patented a technology for tuning a wireless transmitter to broadcast on a precise wavelength. This tuning, Marconi claimed, meant confidential channels could be set up. Anyone who tunes in to a radio station will know that's not true, but it wasn't nearly so obvious back then. Maskelyne showed that by using an untuned broadband receiver he could listen in.
Having established interception was possible, Maskelyne wanted to draw more attention to the technology's flaws, as well as showing interference could happen. So he staged his Royal Institution hack by setting up a simple transmitter and Morse key at his father's nearby West End music hall.
The facetious messages he sent could easily have been jumbled with those Marconi himself sent from Cornwall, ruining both had they arrived simultaneously. Instead, they drew attention to a legitimate flaw in the technology - and the only damage done was to the egos of Marconi and Fleming.
Fleming continued to bluster for weeks in the newspapers about Maskelyne's assault being an insult to science. Maskelyne countered that Fleming should focus on the facts. "I would remind Professor Fleming that abuse is no argument," he replied.
In the present day, many hackers end up highlighting flawed technologies and security lapses just like Maskelyne. A little mischief has always had its virtues.
Paul Marks is senior technology correspondent for New Scientist

From Christmas tree lights to slippers, how tree lights are recycled

Most of us have seen glass and plastic being recycled however recycling of consumer goods made with multiple materials can be much more challenging. In the past Christmas tree lights have been burnt to obtain the copper but this releases a slew of toxic chemicals into the air from the burning plastic. A better solution has been found by a Chinese recycling company that specializes in recycling all the material from light strings once they have served out their time on trees, roofs and gardens.

Tuesday, December 27, 2011

Best Buy selling $1095.99 HDMI cable

Allow me to present the AudioQuest - Diamond 3.3' High-Speed HDMI Cable. Available for a limited time for only $1095.99

This HDMI cable features a Dielectric-Bias System that reduces distortion and 100% Perfect-Surface Silver conductors for improved signal clarity. The Direct-Silver-plated HDMI connectors provide a simple connection and durability.

  • HD polyethylene composition
    Optimized to ensure critical signal-pair geometry.
  • 100% Perfect-Surface Silver conductors
    For improved signal clarity. All signal conductors controlled for digital-audio direction.
  • Dielectric-Bias System
    Reduces distortion.

I paid $15 for my HDMI cable .... I hate to think how much of the picture I'm missing because I didn't pay the extra $1080.99! I've probably got signals going all over the place because my conductors aren't controlled for digital-audio direction .... Oh well, live and learn!

Best Buy Link here

What we can learn from a Mexican drug cartel.

The AP carried the following article detailing an extensive, low cost & flexible radio repeater system employed by a Mexican drug cartel to coordinate their operations. The system seems to exceed the sophistication of regular amateur radio linked repeaters while improving on independence from grid power. America's ham radio community has the required technology, know-how and government support to upgrade our repeater systems ... what is stopping us from pushing the technology further?

Mexico's cartels build own national radio system

MEXICO CITY (AP) — When convoys of soldiers or federal police move through the scrubland of northern Mexico, the Zetas drug cartel knows they are coming.
The alert goes out from a taxi driver or a street vendor, equipped with a high-end handheld radio and paid to work as a lookout known as a "halcon," or hawk.
The radio signal travels deep into the arid countryside, hours by foot from the nearest road. There, the 8-foot-tall (2-meter-tall) dark-green branches of the rockrose bush conceal a radio tower painted to match. A cable buried in the dirt draws power from a solar panel. A signal-boosting repeater relays the message along a network of powerful antennas and other repeaters that stretch hundreds of miles (kilometers) across Mexico, a shadow communications system allowing the cartel to coordinate drug deliveries, kidnapping, extortion and other crimes with the immediacy and precision of a modern military or law-enforcement agency.
The Mexican army and marines have begun attacking the system, seizing hundreds of pieces of communications equipment in at least three operations since September that offer a firsthand look at a surprisingly far-ranging and sophisticated infrastructure.
Current and former U.S. law-enforcement officials say the equipment, ranging from professional-grade towers to handheld radios, was part of a single network that until recently extended from the U.S. border down eastern Mexico's Gulf coast and into Guatemala.
The network allowed Zetas operatives to conduct encrypted conversations without depending on the official cellphone network, which is relatively easy for authorities to tap into, and in many cases does not reach deep into the Mexican countryside.
"They're doing what any sensible military unit would do," said Robert Killebrew, a retired U.S. Army colonel who has studied the Mexican drug cartels for the Center for a New American Security, a Washington think tank. "They're branching out into as many forms of communications as possible."
The Mexican army said on Dec. 4 that it had seized a total of at least 167 antennas, 155 repeaters, 166 power sources, 71 pieces of computer equipment and 1,446 radios. The equipment has been taken down in several cities in the Gulf coast state of Veracruz and the northern states of Nuevo Leon, Coahuila, San Luis Potosi and Tamaulipas.
The network was built around 2006 by the Gulf cartel, a narcotics-trafficking gang that employed a group of enforcers known as the Zetas, who had defected from Mexican army special forces. The Zetas split from the Gulf cartel in 2010 and have since become one of the nation's most dominant drug cartels, with profitable sidelines in kidnapping, extortion and human trafficking.
The network's mastermind was Jose Luis Del Toro Estrada, a communications expert known as Tecnico who pleaded guilty to conspiracy to distribute cocaine in federal court in Houston, Texas, two years ago.
Using millions of dollars worth of legally available equipment, Del Toro established the system in most of Mexico's 31 states and parts of northern Guatemala under the orders of the top leaders in the Gulf cartel and the Zetas. The Gulf cartel boss in each drug-smuggling territory, or plaza, was responsible for buying towers and repeaters as well as equipping his underlings with radios, according to Del Toro's plea agreement.
Del Toro employed communications specialists to maintain and run the system and research new technology, according to the agreement.
Mexican authorities, however, presented a different picture of the cartel radio infrastructure, saying it was less monolithic than the one described by U.S. authorities. A Mexican military official denied that the army and navy have been targeting one network that covered the entire Gulf coast. The operations had been focused on a series of smaller, local systems that were not connected to each other due to technical limitations, he said.
"It's not a single network," the official told The Associated Press on condition of anonymity due to the sensitivity of the topic. "They use it to act locally."
In recent years, reporters traveling with the Mexican military have heard cartels using radio equipment to broadcast threats on soldiers' frequencies. The military official told the AP that the signals are now encrypted, but cartels are still trying to break in.
At least until recently, the cartel's system was controlled by computers that enabled complex control of the radio signals, allowing the cartel to direct its communications to specific radios while bypassing others, according to Grupo Savant, an intelligence and security consulting firm in Washington that has firsthand knowledge of Mexico's cartel operations.
The radio system appears to be a "low-cost, highly extendable and maintainable network" that shows the Zetas' sophistication, said Gordon Housworth, managing director of Intellectual Capital Group, LLC, a risk- and technology-consulting firm that has studied the structure and operations of Mexican cartels and criminal groups.
Other Mexican criminal organizations maintain similar radio networks, including the Sinaloa cartel, based in the Pacific coast state of the same name, and the Barrios Azteca street gang, which operates in Ciudad Juarez, across from El Paso, Texas, a U.S. law-enforcement official said. The Zetas' system is the largest, however, the official said, speaking on condition of anonymity because of the sensitivity of the topic.
The Mexican raids are "a deliberate attempt to disrupt the business cycle of the cartels," said one former law-enforcement official with direct knowledge of the network. "By going after command and communications you disrupt control."
Law-enforcement officials and independent analysts described the operations against the Zetas' communications system as significant short-term victories in the fight against the cartel.
"The seizures show that the organization is scrambling," said Steven Dudley, co-director of InSight, a group that analyzes and investigates organized crime in Latin America.
The longer-term impact is unclear. The cartel has had little difficulty in replacing radio gear and other equipment seized in smaller operations in recent years. And contacts among the highest-ranking Zetas operatives tend to take place in highly encrypted communications over the Internet, according to Grupo Savant.
Certainly, cartel radio equipment is a near-ubiquitous presence for Mexicans living along the front lines of the drug war.
In the state of Tamaulipas, across the border from eastern Texas, many antennas are concealed in the foliage of the rockrose, an invasive shrub that has spread across much of the state's open land.
Even from a few feet (meters) away it's nearly impossible to see the towers or their power cables.
In Nuevo Laredo, the Zetas' first stronghold, antennas sprout from rooftops and empty lots. One soldier told the AP that even when authorities took down an antenna there, it was swiftly replaced.
Associated Press writers E. Eduardo Castillo in Mexico City and Efrain Klerigan in Victoria, Tamaulipas, contributed to this report.

Thursday, December 22, 2011

Coil Winding using the Gingery Coil Winder

Anyone who has seen the video below from KC9KEP will probably be wondering where he got the coil winder used to make those high Q coils with universal windings.

The design itself is based on the Morris Register Company (MoReCo) Coilmaster and modified for home brewing by Dave Gingery. His excellent book is available from and provides plans that use parts and tools commonly available in the home workshop.

Gingery coil winder by KC9KEP
Another resource for coil winders is a page from K5BCQ that shows the original Coilmaster, a different home brew plan and a large volume of useful information.
A vintage text is also available which covers inductor (coil) design in significant detail and should be downloaded by anyone who REALLY wants to know what they are doing. It is available here.

Preserving the past - Australian built broadcast transmitters

Arguably some of the best looking radio equipment was produced in the 50's and 60's when art-deco motifs, streamlining and other elements of design made their way onto consumer and even industrial electronics.
Unlike modern times, when cost is the only consideration, designers and engineers took the time to ensure that their creations looked good as well as being functional and long lasting. It was worth taking time over the placement of meters, switches & panels, even if it did mean that the final product cost a few dollars more to manufacture.
Amalgamated Wireless (Australasia) or AWA produced an extensive range of home and commercial equipment in the 60s and many vintage radio collectors have examples of AWA radio receivers in their collections. The larger equipment like broadcast transmitters takes an extra special effort to preserve as their large size, demanding power requirements and the specialized knowledge required to maintain them presents a barrier for all but the most dedicated enthusiasts.
We are fortunate then that Don Bainbridge has taken up the challenge and preserved a remarkable collection of Australian built broadcasting equipment and maintains much of this equipment in operational order. The YouTube video below and his website linked here offer a rare glimpse into the world of vintage high powered broadcast equipment before plastic took over and economical design stripped away the chrome and pinstripes.

Sunday, December 18, 2011

Bad news for kit builders in the EU

G4ILO Writes ...

I’m not the first blogger to mention this item of news but it is certainly one topic that I could not allow to pass by without comment. According to the IARU Region 1 website, the EU Commission will be revising the EMC Directive and removing the exemption of amateur radio kits and modified equipment from its provisions. Products that are currently exempted would be subject to inspection and certification, a process which would make the production of kits hopelessly uneconomic. It would also potentially spell the end of home building and modification and prevent the importation of kits from the USA and other havens of relative sanity. No, this isn’t one of my April 1st spoof stories released from the Drafts folder by mistake!
I would hope that the IARU, the RSGB and other European amateur radio societies will make urgent representations to the EC to stop this proposal. But this is just one scary example of why I and many other like-minded people feel that we in the UK would be better off out of the European Union.
In fact, most of Europe would be better off without it in my opinion. Could somebody explain why, at a time when European governments are supposed to be cutting back on public expenditure, they continue contributing billions every year (only recently having voted an increase – the UK alone contributes £51 million per day) in order to fund this unelected and unaccountable Commission to employ people who live in cloud cuckoo land to produce unwanted, unnecessary and unasked-for legislation?

Original Article

Thursday, December 15, 2011

Jet engines take to the rails, in 1970

In the 1970's Canada added five turbine powered trains to their rail system. Known simply as the Turbo it had several innovative features such as articulation and tilting as well as state of the art power and control systems. The video below was shot in 1970 and outlines the construction process, technology and performance of the new system.

From Wikipedia:

In May 1966 Canadian National Railways ordered five seven-car TurboTrains for the Montreal-Toronto service. They planned to operate the trains in tandem, connecting two trains together into a larger fourteen-car arrangement with a total capacity of 644 passengers.

The Canadian trains were built by Montreal Locomotive Works, with their ST6 engines supplied by UAC's Canadian division (now Pratt & Whitney Canada) in Longueuil, Quebec. CN and their ad agency wanted to promote the new service as an entirely new form of transit, so they dropped the "train" from the name. In CN's marketing literature the train was referred to simply as the "Turbo", although it retained the full TurboTrain name in CN's own documentation and communication with UAC.

A goal of CN's marketing campaign was to get the train into service for Expo '67, and the Turbo was rushed through its trials. It was late for Expo, a disappointment to all involved, but the hectic pace did not let up and it was cleared for service after only one year of testing - most trains go through six to seven years of testing before entering service.

The Turbo's first demonstration run in December 1968 with Conductor James Abbey of Toronto, Ontario in command, included a large press contingent. An hour into its debut run, the Turbo collided with a truck at a highway crossing near Kingston. Despite the concerns that lightweight trains like the Turbo would be dangerous in collisions, the train remained upright and largely undamaged. Large beams just behind the nose, designed for this purpose, stopped the collision and limited the damage to the fiberglass clamshell doors and underlying metal. The train was returned from repairs within a week. No one was killed, though this event has been cited as a main deterrent to Canada’s efforts to develop modern passenger rail.

Initial commercial service started soon after. On its first westbound run the Turbo attained 104 mph (167 km/h) 10 minutes outside of Dorval. During speed runs, it achieved 140.55 mph (226 km/h) near Gananoque, Ontario, the Canadian record to this day.

Technical problems, including brake systems freezing in winter, required a suspension of service in early January 1969. During the "downtime" CN changed their plans, and in 1971 a rebuild program began, converting the five seven-car sets to three nine-car sets. Several minor changes were added. The engine exhaust fouled the roof windows of the power car, so these were plated over, and a grill was added to the front of the engines just behind the clamshell doors. The remaining power and passenger cars were sold to Amtrak as two 4-car sets. One of those sets sideswiped a freight train on a test run in 1973 and burned before delivery. The three rebuilt 9-car sets entered service for CN in late 1973. CN ran the Turbos from Toronto-Montreal-Toronto with stops at Dorval, Quebec, Kingston, Ontario and Guildwood, Ontario on the Quebec City-Windsor Corridor.

Original train numbers were Train 62 which left Toronto at 12:45 p.m. and arrived in Montreal at 4:44 p.m. Train 63 left Montreal at 12:45 p.m. and arrived in Toronto at 4:44 p.m. (Both were daily trains.) Train 68 left Toronto at 6:10 p.m. and arrived in Montreal at 10:14 p.m., while Train 69 left Montreal at 6:10 p.m. and arrived in Toronto at 10:14 p.m. (The evening trains did not run on Saturdays.) The trip took 3 hours and 59 minutes downtown-to-downtown on trains 62 and 63, while the evening trains were slightly slower, taking four hours and four minutes to complete the run. Turbo service was about a full hour faster than CN's previous express trains, the "Rapido".

CN operated the Turbos until 1978, when their passenger operations were taken over by Via Rail, who continued the service. The Turbo's final run was on October 31, 1982, when they were replaced by the all-Canadian LRC trainsets from Bombardier Transportation, which employed conventional diesel-electric locomotives. Although they had an early reputation for unreliability, according to CN's records, the rebuilt TurboTrains had an availability rate of over 97% for the their careers with CN and Via. The LRC suffered from similar teething problems, notably with the tilt system locking the cars in a tilted position.

Better than X-Ray glasses

While not as simple as putting on a set of EM vision goggles this is still opens the window into visualizing radio waves and allows us to see what we previously had to imagine.

Greg Charvat N8ZRY just published this video showing off a very cool experiment with the low-cost coffee can radar system he and co-workers developed, in the fall of 2010, for MIT’s open courseware initiative.

In the video, Greg describes and demonstrates a simple circuit that causes a red/green LED on the receiving antenna to glow one color when the amplitude of the received wave is positive, and another when it is negative. Moving the LED back and forth in front of the transmitter, while taking a long-exposure photograph, gives a visual map of the wavefront in space.

Tuesday, December 13, 2011

iPads and e-Readers as book replacements?

I've recently started to acquire reference books as PDF files since getting an iPad. I was initially skeptical of this idea after being disappointed trying to read PDF files on a Sony e-ink device. After some software updates and a little experimenting I have found the iPad to be a completely different experience.

The large screen size and, more importantly, the quick navigation have made the iPad a logical choice for reading though a book, magazine or reference manual. Now that Apple has made some tweaks to the book reading application you are now able to sort PDF files into collections and this improves on the slightly clunky, although intuitive, bookshelf metaphor.

The cost is certainly an issue as iPads are not cheap and are rarely discounted. I will suggest that there are other factors which should be balanced against the initial cost:
  1. Convenience: The iPad is always the same size and weight. No matter if it carrying one book or one-thousand it remains a convenient size that can be slipped in a backpack or carried in a case.
  2. Speed: There are several features in software that allow you to quickly turn to the exact page you require or look-up a reference or keyword in the text. Even older books that have been scanned benefit from being able to see many pages at once or bookmark multiple pages for reference later.
  3. Intuitive interface: The bookshelf metaphor used by the iPad's reading application is expanded by the idea of collections of books that the user can manage. Pages are turned by taps or swipes and a single tap in the center of the page brings up additional navigation options. Other iPad gestures like 'pinch to zoom' also allow you to zoom on details or expand a diagram to fill the whole screen.
  4. Long term cost of ownership: Reference books, in particular educational text books, are often priced over $100 USD for a single volume. The same books are often available for much less in electronic format due to the elimination of printing, shipping and storage costs. For people such as myself the books I would like to own are often out of print or, if copies are still available, they are being sold at exorbitant prices. The iPad makes it possible for me to own and enjoy these books with the additional benefit of them not taking up shelf space.
An Apple iPad running the Books application.
There are other tablet devices available and I have used a few for brief periods of time while evaluating different applications. It is my impressions that the iPad does a better job of integration between applications and maintains a consistent user interface across all its applications. There are certainly more options for customization and experimentation on other platforms but for straightforward functionality Apple have the lead at the moment.

As a book collector I hope that we continue to see books printed and I will certainly keep collecting antique books but I do foresee a time when digital books will become the dominant media. I think we have only seen the tip of the iceberg when it comes to digital books, there is much more to come.

To read more about the impact of the Apple iPad in Schools read : Goodbye Textbooks, Hello iPad from PCWorld

Neurosurgical tool developed by amateur radio operator Dr. Kim H. Manwaring N7DFU

A University of Utah surgeon has performed the first successful procedure with the FMwand, a new medical device developed by Salt Lake City-based Domain Surgical that, in essence, acts as a bloodless knife, cauterizing as it cuts.

The device was invented in the Utah basement of a pediatric neurosurgeon, Dr. Kim Manwaring N7DFU. Manwaring was on a quest to find a material that could deliver precise heat. Tinkering in his basement with parts from a ham radio, he came up with the concept for the device and then came across a special alloy developed by a NASA engineer, which he used for the tip of the instrument.

The FDA recently cleared the device for use in humans. Joel MacDonald, M.D., a neurosurgeon with the University of Utah’s Clinical Neurosciences Center and an associate professor in the School of Medicine, used the FMwand during three surgical procedures this week—twice for spine surgeryand once for brain surgery.

Complete article at

Sunday, December 11, 2011

LightSquared and GPS interference.

LightSquared is a company that plans to provide a wholesale, nationwide 4G-LTE wireless broadband network that includes satellite coverage. LightSquared plans to combine existing mobile satellite communications services with a ground-based wireless communications network that uses the same L-band radio spectrum as the satellites.

However the signals for the LightSquared base stations will be transmitted on a frequency immediately adjacent to those used for the existing Global Positioning System (GPS). A draft report suggested that 75% of GPS receivers would be affected by harmful interference when located 100 meters from a LightSquared base station. LightSquared are naturally upset that the draft report had been leaked and have stated that they plan to operate their equipment at lower power levels which would affect 10% of devices.

If I were certain of their intent to run lower power levels I would still find this to be an unacceptable situation. I'm positively sure that if the amateur radio community proposed to operate in a manner that caused harmful interference to 10% of GPS units we'd be shutdown so fast our heads would spin.

GPS receivers, while not falling under the same category as emergency radio systems, are none-the-less an essential service for the smooth running of society. GPS has integrated itself into almost every portable electronic device and are used for much more than just navigation. Allowing LightSquared to continue without serious real world testing would be the worst way to find out how essential GPS had become and just how much it would cost to have it disrupted. More details are available on the website of the National Executive Committee on Space-Based Positioning Navigation and Timing

Friday, December 9, 2011

Cooler weather is coming to town.

Thankfully we're seeing some cooler weather in Houston. Finally our AC system can take a break and if it gets REALLY cold we may even kick the heat on for a bit.

Every house had a roof white with frost this morning.

Pedestrian mobile and the magnetic loop with VK3YE

I've been using a 40M magnetic loop antenna for a while now and have been impressed with the low noise and high performance, especially considering its stuck in the middle of my garage!

I'd been thinking about a smaller loop that could sit in the attic with a remote tuner but had been put off by the critical requirements ... minimal dc resistance etc.

Now I have seen Peter and his portable loop I may have to reconsider brewing something up and giving it a shot. I'd like it to handle a bit more than 5W but that should be achievable with parts I already have in the junk box.

Wednesday, December 7, 2011

Old Time Radio (OTR) at

When tuning across the AM broadcast band I'm often reminded that there is little left but sports radio and talk shows. I'm not particularly against either but I remember that in the past there was a lot more to pick from. With this in mind I have been looking around the Internet for a source of old time radio and found an excellent storehouse at

I noticed while talking with friends that not too many people know about or assume its only used to hold podcasts. Nothing is further from the truth.

Take a look at  for an excellent collection of old time radio shows and once you've had your fill there, take a look at and the video archives.

For a quick taste click the play button below and listen to Strange Tales.

Tales of the strange and bizarre, the weird and the wicked. Stories not necessarily of the supernatural, but of the unnatural

(If the player doesn't appear you may need to go to and listen to the radio show there)

Tuesday, December 6, 2011

The Animals - House of the Rising Sun played on vintage electronics.

This must have taken a while to put together. The idea to use the scanner as a musical instrument is not new but getting it to play well is not easy. I think he did a great job in keeping the different devices in sync, particularly considering they don't share common interfaces or protocols!

Quick Iambic keyer using the Arduino micro-controller

With the multitude of inexpensive development boards like the Arduino it has become possible to add micro-controllers to just about everything. Projects that previously required custom designed circuits are now implemented by connecting to the input and output ports on a development board. Programming has become easier as well due to the development of simple and efficient software with libraries of sample code to modify and reuse for your own projects.

Costs have fallen dramatically with the development board featured below selling for approximately $30. At that price it could be the heart of automatic antenna tuners, rotor controllers or a keyer as shown below.

Dimitris Sapountzakis quickly home-brewed a set of touch paddles from spade connectors and perf board. 

Touch paddles made from spade connectors and perf board.
Once connected to the Arduino micro-controller he was able to use those inputs to control they keyer code he wrote. Because the logic is in software rather than hardware he could add automatic ID, contest modes or practically any any other function as simply as changing a few lines of software.

With micro-controller prices being as low as they are now we may start to see a renascence in home-brewing and kit building. Much as ham radio kits educated an earlier generation, economical micro-controllers may allow this generations an avenue to experiment, design and create tomorrow technology.

Sunday, December 4, 2011

Build your own computer for $40 ? yes you can ...

FIGnition is a simple, educational computer, but a real one, not an emulator. It has real firmware, real RAM, really generates a display, really has storage for when you turn the machine off (roughly the size of an 80s floppy disk).

I remember kits like this from when I was a kid but they were never so simple to get up and running as the FIGnition. This is a great learning tool for schools or individuals who want to explore computer internals.

Click here to go to the FIGnition site :

FIGnition is a $40 educational DIY computer which works like an 8-bit home Micro: outputting to composite video and ready to be interactively programmed from the moment you switch it on. It has  8Kb of RAM; 384Kb of storage; an 8-key keypad and runs a variant of FIG-Forth. It uses USB for power; firmware upgrades and program downloads.

1960's style guerilla homebrew 6 Hz - 2 MHz function generator with 4 transistors

A very neat construction project from Miroslav Cika. Miroslav's project generates square waves up to 2.22 MHz and pulses with a variable duty cycle from 1-49% and 51-99%. Output is either 5 Volt TTL levels or an adjustable 0-3.38 level. 

This piece of test equipment could be very useful for designing and debugging digital electronics. The design is flexible enough that it can be modified to suit your needs.

Click the following link to go to his page describing the build process :

Front view showing controls
Circuit diagram, just four transistors.
Output at 1Mhz on scope

Considering a small HF antenna? You have to read this ...

I came across this explanation of the limitations of stealth/small antennas by Dan Zimmerman, N3OX. He has provided the best explanation of the physics behind 'short' antennas that I have seen so far.

This should be required reading for anyone considering one of the stealth antenna designs such as the Tak-tenna, Isotron or Crossed Field Antennas.

I hope Dan won't mind me copying his explanation from It is worth your while to head over to his web site and see some of his home brew antenna projects, there are excellent explanations provided as well as the thinking that went into each design.

Once you've had a read below go on over to: and take a look at Dan's website.

"In theory, a short antenna can be made efficient enough to compare very well to a full size version, but the tradeoffs (lower impedance, narrower bandwidth) are inescapable and you need to address them carefully to make it work well in practice"

And the *most important thing* for hams who need small antennas like KB3HJK does is to never forget that those tradeoffs are fundamental.

In order to radiate a certain amount of RF power into the universe with a short dipole, you *have to increase the current* flowing along the straight bit many times over what has to flow in a half wave dipole.

If you make a very short/small antenna and want to *radiate* the same amount of power, that *requires* a much higher current flowing in the radiating part of the antenna, period.

In order to pump more current through the antenna without causing significant losses, you have to reduce the loss resistance significantly compared to a big antenna.

And an antenna that needs lots of current to radiate a given amount of power is said to have a "low radiation resistance"

The power lost to heat in an antenna is basically I^2*Rloss (the antenna current squared times the loss resistance) The power radiated is I^2*Rrad (current squared times radiation resistance).

So what does this have to do with bandwidth? Well, a couple of things. One is that when you make an antenna smaller and drive high currents in it, you make a LOT more electrons slosh back and forth in a small physical space. To focus on a short cap hatted dipole, there's a LOT of magnetic field caused by the very strong current (lots of electrons per cycle) flowing through the horizontal dipole part, and there's a LOT of electric field caused by lots of electrons piling up on the capacitance hats, first one and then the other, as the RF cycle progresses.

A capacitance hat charges up on one part of the RF cycle, a quarter cycle later, all those electrons are rushing at maximum speed toward the other hat, another quarter cycle later, they're piled up on the 2nd hat, and another quarter cycle later they're rushing back toward the first hat. Energy is exchanged between the electric field, largely between the hats and the magnetic field as the electrons are rushing through the horizontal conductor.

Since everything is so compact, the electric and magnetic fields are very strong, and store a lot of energy near the antenna.

But we also know something else... we know that the radiation resistance is very small, and to make the antenna efficient, we must reduce the loss resistance. So the *total resistance* is very low. The resistance is associated with the energy lost per cycle of RF. Some goes to heat in the loss resistance, some goes to radiation, "dissipated" in the radiation resistance.

But if you compare the energy *stored in the fields around the antenna* vs. the energy *lost per cycle*, you find that there's a lot of energy stored vs. how much is dissipated in the radiation and loss resistances. The strong fields make the stored energy high, the low resistances make the dissipation small.

So the antenna is very "high Q." If you cut power to a very high Q antenna, it will ring down for a relatively long time as the stored energy is damped by the dissipation into loss and radiation. But we know from other circuits that high Q resonant circuits are very sharply tuned, and a small antenna is no exception. It has a very narrow bandwidth over which you can slosh current back and forth effectively in a resonant way.

Since the radiation resistance and the stored energy in the fields is fixed by the size and shape of the antenna, the only way to broaden the response of a certain size antenna with fixed tuning is to add losses!!!

This is fundamental, and will steer you away from very small, broad bandwidth antennas if you keep it in mind. You absolutely, positively must give up bandwidth to keep efficiency at small size.

This is why the very best tiny antennas will all be motor driven. Magnetic loops and mobile screwdriver antennas with capacitance hats are two great examples of how to get around the narrow bandwidth problem. Sure, the antenna is 10kHz between the 2:1 SWR points, but if you can tune that 10kHz anywhere you want between 5 and 21 MHz, who cares?

But there's even a point where motor drive doesn't save you. There's even a point where superconducting antennas don't save you.

There's a lower limit that few talk about (except a few crazy magloop guys who come close to running up against it)

If you make a very very tiny, extremely low radiation resistance antenna and you stamp out almost all the losses by welding together huge conductors, your antenna's bandwidth could become so narrow as to not pass even a SSB signal. ;-)

You'd actually roll off your audio if you had a 1kHz wide magnetic loop and could make the tuning stable!

But this is the basic fact you need to remember when antenna shopping. Quite small antennas should be easily retunable in small steps across a ham band, otherwise they are required to be *quite* lossy to give good SWR bandwidth. No matter what any manufacturer says, a tiny antenna needs to be VERY small in bandwidth for it not to be lossy.

And KB3HJK, as far as that particular HF-p antenna goes? It's nearly impossible to know exactly but I expect that since it covers 200kHz of 40m with no retuning and is only 10 feet long, it's probably going to be about 1% efficent.

For comparison, I built a 40 foot long 40m dipole with a loading/matching coil at the feedpoint that should have been about 80% efficient (-1dB) and was about 70kHz between the 2:1 SWR points. End loading could improve that, but the HFp isn't end loaded.

If you really need to get on 40m better than you have been in the sort of 3-10 foot antenna class, your next antenna should have a motor.

Or if you're worried about feedline radiators because you can put the antenna 20 feet up on a pole, just go ahead and make the pole the antenna instead. N0LX has some interesting voltage fed "loaded end fed half waves" on his website, and they actually model reasonably well.

And even a Tak-Tenna type antenna is maybe OK, the problem with them is that there's NO REASON to use a 30 inch antenna on 40m. It's too short. Do the same thing but make it 15 feet long and you'll be much better off.


Learning morse code? This is a great resource!

The Straight Key Century Club has made available classic books in morse code. HG Wells, "War of the Worlds" initially starts out at 10 words per minute increasing one word per minute each chapter until the last chapter is sent at 36 words per minute.
Many classic books are available at in mp3 format.
Not having made much progress on learning CW myself this may be the motivation I need to start, I've never been able to resist a good yarn by HG Wells.

Thursday, December 1, 2011

Wartime Radio: The Secret Listeners

This is a great documentary filmed in 1979. It tells the story of amateur radio operators intercepting German Naval messages and the development of secret listening posts in the UK. Lots of good footage and history along with interviews with historic personalities.

Illustrated with archival film and photographs, as well as interviews with those involved, the documentary traces the evolution of civilian involvement in radio-based intelligence during both world wars.

It was the tireless work of amateur radio enthusiasts during World War I, that initially convinced the Admiralty to establish a radio intercept station at Hunstanton. Playing an integral role during the war, technological advances meant that radio operators could pinpoint signals, thus uncovering the movement of German boats, leading to the decisive Battle of Jutland in 1916.

Wireless espionage was to play an even more important role during World War II, with the Secret Intelligence Service setting up the Radio Security Service, which was staffed by Voluntary Interceptors, a band of amateur radio enthusiasts scattered across Britain. The information they collected was interpreted by some of the brightest minds in the country, who also had a large hand in deceiving German forces by feeding false intelligence.