ARRL membership is about , Thanks to reunification, Germany has the largest number of ama teurs of any European country. The United Kingdom has nearly as many amateurs as Germany.
The total member ship of the RSGB is about 30, Still, Indonesia is in no danger of losing its top status. Spain is another country where Amateur Radio has experienced rapid growth in recent years. Ham radio license exams are given by trained volunteers across the country.
Licenses are issued by the FCC itself, usually within a few weeks after you pass your license exam. Your license is valid as soon as it appears on the FCC's online database. You do not have to wait for your paper license to arrive before operating as long as your callsign is listed on the FCC database.
VE sessions are held at convenient times and locations in every state. Most are in the evenings or on weekends. Special sessions may also be arranged for test candidates with special needs who may be unable to get to a regularly scheduled sessions.
Many examiner groups hold monthly or bi-monthly sessions. There is a nominal fee for taking the exam, which is set each year by the FCC.
Ask for their Prospective Ham Package and be sure to include your name and mailing address. If you live near a state line, request listings for the adjacent state, as well. The package is free. In addition to the exam lists, the ARRL package will include a list of ham radio clubs and registered instructors in your area. The ARRL American Radio Relay League is the major national organization of ham radio operators in the United States, with more than , members, a nationwide volunteer "field organization," public service and emergency networks, Washington representation and much, much more.
Every active ham should belong to the ARRL. One of the ARRL's goals is to promote the growth of amateur radio. The regulations of most countries around the world provide for this opportunity through Amateur Radio.
In the United States, Amateur Radio regulations are administered by the Federal Communications Commission, the same branch of government that oversees the licensing of broadcast stations and other users of the radio spectrum. Hundreds of thousands of ordinary people of all ages and from all walks of life and all educational backgrounds have obtained their Ham licenses.
Their main interests in radio may be technical, recreational, social or educational. To become a Ham, one must pass the required examination on electronic theory, operating practices and governing regulations. Higher power limits, specialized antennas, a variety of operating modes voice, digital, video, etc. Public service is an underlying reason that the Amateur Radio Service exists. During conflicts such as World War II, Hams provided the military with a pre-trained pool of experienced communicators and technicians.
During peacetime, Hams have communicated all over the world, spreading goodwill and making friends in other parts of the globe. Technically oriented Radio Amateurs have advanced the state of the art and pioneered new ways of communicating that were later adopted by government and commercial users.
Ham radio has been used in classrooms to get children interested in science. And, importantly, many hams have volunteered their time, equipment and knowledge to support local, regional and international response and relief work in times of disaster. Our government agencies have huge investments in rugged, high-technology communications equipment that serve them well on a day-to-day basis. So why do communications failures seem to happen at the worst times? The two basic causes are overload and infrastructure failure.
Amateur radio can often overcome both these limitations. Most communications systems are designed to handle a certain normal load level. Telephones work as long as only a given number of customers are using them at any one time.
If half the phones in the City are off the hook due to the shaking of an earthquake or to people checking on the welfare of friends and relatives, parts of the system will shut down. The tower-mounted equipment that processes our cellular phone calls can accommodate only a small percentage of their subscribers using the system at one time, even absent an emergency. Too many calls at once, even during heavy commuting times, can tax the limits of that equipment. Demand during disasters can push everyday systems into overload, shutting out many users.
Amateur Radio operators have a continuum of available frequencies inside designated bands from which to choose, rather than a set of discrete channels, so finding a suitable frequency to support a specific communication path is almost never a problem. Most communications systems routinely run on commercial electric power, the same power that runs your home and workplace. When that power fails in a disaster, those systems without generator or battery back-up are out of service.
If large generators are knocked over by a quake, if they are not run regularly, or if their fuel supply is stale, they may not work. If batteries are not properly maintained, they may be exhausted quickly. No power means no communication. Many Amateur Radio operators use equipment that can be powered from internal batteries, car batteries or other common sources of volt DC electricity.
If the central computer is knocked out, the system fails. VHF and UHF systems may rely on remote relay stations, called repeaters, to get signals over the hills and mountains that dot their service areas. If the repeaters lose power or are otherwise out of service, the range or reach of the system becomes more limited.
Hams use repeaters, too, but they can also operate without them if necessary. Explore tools and applications that can be used to look into the future. Game-Changing Opportunities. This course explores the impact advanced technology is likely to have on industries including agriculture, energy, education, finance, and health care.
Implementation—From Theory to Practice. This session focuses on psychological, social, and political considerations that could help with deployment. Individuals who complete the course program can earn up to 0. Institutions interested in the program can contact an IEEE account specialist to learn more.
To learn more about how digital transformation can impact your company, register for The Benefits of Digital Transformation for Organizations , a free virtual event to be held on 16 November at noon New York time. The session will be available on demand two hours after the live event concludes. It turns out that you don't need a lot of hardware to make a flying robot.
Flying robots are usually way, way, way over-engineered, with ridiculously over the top components like two whole wings or an obviously ludicrous four separate motors. Maybe that kind of stuff works for people with more funding than they know what to do with, but for anyone trying to keep to a reasonable budget, all it actually takes to make a flying robot is one single airfoil plus an attached fixed-pitch propeller.
And if you make that airfoil flexible, you can even fold the entire thing up into a sort of flying robotic swiss roll. This type of drone is called a monocopter, and the design is very generally based on samara seeds, which are those single-wing seed pods that spin down from maple trees. The ability to spin slows the seeds' descent to the ground, allowing them to spread farther from the tree. It's an inherently stable design, meaning that it'll spin all by itself and do so in a stable and predictable way, which is a nice feature for a drone to have—if everything completely dies, it'll just spin itself gently down to a landing by default.
F-SAM stands for Foldable Single Actuator Monocopter, and as you might expect, it's a monocopter that can fold up and uses just one single actuator for control. There may not be a lot going on here hardware-wise, but that's part of the charm of this design. The one actuator gives complete directional control: increasing the throttle increases the RPM of the aircraft, causing it to gain altitude, which is pretty straightforward. Directional control is trickier, but not much trickier, requiring repetitive pulsing of the motor at a point during the aircraft's spin when it's pointed in the direction you want it to go.
F-SAM is operating in a motion-capture environment in the video to explore its potential for precision autonomy, but it's not restricted to that environment, and doesn't require external sensing for control.
While F-SAM's control board was custom designed and the wing requires some fabrication, the rest of the parts are cheap and off the shelf. If you look closely, you'll also see a teeny little carbon fiber leg of sorts that keeps the prop up above the ground, enabling the ground takeoff behavior without contacting the ground.
You can find the entire F-SAM paper open access here , but we also asked the authors a couple of extra questions. IEEE Spectrum: It looks like you explored different materials and combinations of materials for the flexible wing structure. Why did you end up with this mix of balsa wood and plastic?
Shane Kyi Hla Win: The wing structure of a monocopter requires rigidity in order to be controllable in flight. Although it is possible for the monocopter to fly with more flexible materials we tested, such as flexible plastic or polymide flex, they allow the wing to twist freely mid-flight making cyclic control effort from the motor less effective.
The balsa laminated with plastic provides enough rigidity for an effective control, while allowing folding in a pre-determined triangular fold.
Can F-SAM fly outdoors? What is required to fly it outside of a motion capture environment? Yes it can fly outdoors. It is passively stable so it does not require a closed-loop control for its flight.
The motion capture environment provides its absolute position for station-holding and waypoint flights when indoors. For outdoor flight, an electronic compass provides the relative heading for the basic cyclic control. We are working on a prototype with an integrated GPS for outdoor autonomous flights. A camera can be added we have done this before , but due to its spinning nature, images captured can come out blurry. A conventional LiDAR system requires a dedicated actuator to create a spinning motion.
Your paper says that "in the future, we may look into possible launching of F-SAM directly from the container, without the need for human intervention. Currently, F-SAM can be folded into a compact form and stored inside a container. However, it still requires a human to unfold it and either hand-launch it or put it on the floor to fly off.
In the future, we envision that F-SAM is put inside a container which has the mechanism such as pressured gas to catapult the folded unit into the air, which can begin unfolding immediately due to elastic materials used.
The motor can initiate the spin which allows the wing to straighten out due to centrifugal forces. F-SAM could be a good toy but it may not be a good alternative to quadcopters if the objective is conventional aerial photography or videography. However, it can be a good contender for single-use GPS-guided reconnaissance missions.
As it uses only one actuator for its flight, it can be made relatively cheaply. It is also very silent during its flight and easily camouflaged once landed. Various lightweight sensors can be integrated onto the platform for different types of missions, such as climate monitoring. F-SAM units can be deployed from the air, as they can also autorotate on their way down, while also flying at certain periods for extended meteorological data collection in the air.
We have a few exciting projects on hand, most of which focus on 'do more with less' theme.
0コメント