Showing posts with label amateur radio. Show all posts
Showing posts with label amateur radio. Show all posts

Wednesday, January 12, 2011

So You Want to Learn Morse Code - Here Are Some Tips

By Gerald Wheeler

Like music, some people seem to have a natural talent to learn the Morse code effortlessly. During World War II it was common practice to gather a few hundred military recruits into a hall, introduce them to the World of "dahs and dits," and wash out the majority within two weeks. Those remaining "geniuses" became the wireless Aces of the War.
For most students, gaining control over the flow and rhythm of the sounds proved to be an arduous and fearsome task. Code practice machines used at this time consisted of paper rolls about an inch wide that ran past a light source. The rolls were perforated to create, from the electric eye, an almost perfectly sounded string of Morse code letters, numbers and messages. The student was systematically introduced to the character sound, as the instructor called out the letter's name. Soon another string of dots and dashes was added and another until a dizzying array of dahs and dits swam in the student's head. Since the practice sessions often lasted several hours or more, errors were practiced over and over and then when the paralyzing test was given, anxiety ran high with frustration and failure common.
Over the years, most students try to learn Morse code in just this same manner. It is no wonder that when the FCC decided to eliminate the code testing for amateur radio licenses that a great sigh of relief came from many long frustrated "would-be" hams.
However, another method appears to have gained many adherents. In the English speaking countries and in other language parts of the world, Morse code is being taught using a mnemonic system that mimics the sound of the code in the language of the learner. The dahs and dits can be heard as simple words and phrases instead. With this method and only forty characters to learn, a high percentage of students succeed at mastery.
It appears that the brain is capable of learning language quite readily when meaning is attached to sounds. Without meaning in the sounds themselves, the brain has no handles to make an attachment, causing the symbols to become hopelessly mixed. A mnemonic device is defined as: "any learning technique that aids memory. Commonly, mnemonics are verbal (such as a very short poem or a special word used to help a person remember something) but may be visual, kinesthetic or auditory. (Wikipedia.com) Mnemonics rely on associations between easy-to-remember constructs which can be related back to the data that is to be remembered. This is based on the principle that the typical human mind much more easily remembers spatial, personal, surprising, sexual, humorous or otherwise meaningful information than seemingly arbitrary sequences." The seemingly random string of dahs and dits of the letter take on meaning from the associated mnemonic. Thus the letter "D" might be more readily remembered as "Dog did it" instead of "Dah di di." Attach a picture of a hapless canine and "presto" the symbol is forever remembered.
Persons learning the Morse code this way find that they can master the code in a matter of days instead of months and that there really can be a lot of pleasure in acquiring and using this universal foreign language skill.
Gerald R. Wheeler, (Jerry) Ed.D. W6TJP, Author, Educator, Morse Code instructor, Inventor of Code Quick, to help you master morse code the quick and easy way. With the new Code Quick you can learn the most used universal code language around. Morse Code Quick guarantees your success.
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Friday, January 7, 2011

What If Our Communication Systems Fail? Morse Code Can Help

By Gerald Wheeler

Consider your average morning routine. Most of us begin taking in the day's news as soon as the clock radio wakes us up. Then there is the morning news brief from the television while eating breakfast followed by a local radio station during our commute. Throughout the day people continue to glean important events from news sites on the internet. Now consider what your day would look like if all of these resources fell silent.
There are continual reminders that our nation's power grid is much more fragile than we would like to admit. Such threats do exist not only as foreign or domestic, but extra-worldly as well. Modern power grids are managed by computer networks and the potential exists for hacking into those networks to interrupt the power supply. Another less sinister, but just as hazardous threat comes from outside our own planet. The very sun that we rely upon every day occasionally ejects powerful solar flares known as coronal mass ejections or CMEs. These powerful electromagnetic fields can wreak havoc on sensitive electronic components and have already caused major power outages in recent history and scientists continue to predict that the sun is primed for another such event.
The technology for electromagnetic bombs, developed over the past 30 years, is now available to download from on the internet! Googling it demonstrates the ease with which a would-be enemy could devastate society, creating an enormous blackout with mass panic and havoc. Such powerful electronic pulses pose a significant threat to breakdown all traditional communication including satellites that control every aspect of transportation, commerce and ultimately life.
Other potential problems with national and regional grids are not posed by external threats, but by the continued and rapid growth of our own cities. While such power demands are on the rise, the capacity to provide power to them is not keeping pace. The battle between environmental groups and political decision makers only seems to be maintaining the status quo and not improving the reliability of our energy needs.
If any one of these events transpire and our power grid fails, where would we get our news and information? While we could certainly continue to live day-to-day without a sizable amount of the information we take in, there is some information that we simply would find hard to live without. In the case of a regional or national disaster, reliable and accurate information can be the biggest factor in safety and survival.
How fortunate we are that there are trained amateur radio operators scattered across the country who are poised to fill this important gap if ever needed. With an emergency generator and communication tools, these operators have the equipment and coding skills necessary to process and relay important information at a moment's notice. Many of these operators utilize an assortment of methods, but among them Morse code gets through when other methods fail. As we have seen in so many movies, confirmed by actual real life experiences, the effectual transmission of dahs and dits between trained operators is a very useful method of communicating both securely and accurately.
If you prepare by learning Morse code, you will be on the front lines of the vital communication network and could be responsible for bringing peace, comfort and safety information to friends and family. Some things may be better left to others, but wouldn't you feel safer knowing that you have done everything you could do in an emergency? Morse code continues to be a valuable survival skill for you, your family and for the nation.
Gerald Wheeler, Ed.D. W6TJP http://www.cq2k.com
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Friday, October 30, 2009

High Frequency (HF, Shortwave)

High frequency

From Wikipedia, the free encyclopedia


High frequency
Frequency Range 3 to 30 MHz

ITU Radio Band Numbers
edit

High frequency (HF) radio frequencies are between 3 and 30 MHz. Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters (ten to one hundred metres). Frequencies immediately below HF are denoted Medium-frequency (MF), and the next higher frequencies are known as Very high frequency (VHF). Shortwave (2.310 - 25.820 MHz) overlaps and is slightly lower than HF.

Propagation characteristics

Since the ionosphere often refracts HF radio waves quite well (a phenomenon known as skywave propagation), this range is extensively used for medium and long range radio communication. However, suitability of this portion of the spectrum for such communication varies greatly with a complex combination of factors:
These and other factors contribute, at each point in time for a given communication path, to a

Exploitation of, and limits imposed by, these characteristics

When all factors are at their optimum, worldwide communication is possible on HF. At many other times it is possible to make contact across and between continents or oceans. At worst, when a band is 'dead', no communication beyond the limited groundwave paths is possible no matter what powers, antennas or other technologies are brought to bear. When a transcontinental or worldwide path is open on a particular frequency, digital, SSB and CW communication is possible using surprisingly low transmission powers, often of the order of tens of watts, provided suitable antennas are in use at both ends and that there is little or no man-made or natural interference.[1] On such an open band, interference originating over a wide area affects many potential users. These issues are significant to military, safety[2] and amateur radio users of the HF bands.

Uses


A modern Icom M700Pro two-way radio for marine HF radio communications.
The high frequency band is very popular with amateur radio operators, who can take advantage of direct, long-distance (often inter-continental) communications and the "thrill factor" resulting from making contacts in variable conditions. International shortwave broadcasting utilizes this set of frequencies, as well as a seemingly declining number of "utility" users (marine, aviation, military, and diplomatic interests), who have, in recent years, been swayed over to less volatile means of communication (for example, via satellites), but may maintain HF stations after switch-over for back-up purposes. However, the development of Automatic Link Establishment technology based on MIL-STD-188-141A and MIL-STD-188-141B for automated connectivity and frequency selection, along with the high costs of satellite usage, have led to a renaissance in HF usage among these communities. The development of higher speed modems such as those conforming to MIL-STD-188-110B which support data rates up to 9600 bit/s has also increased the usability of HF for data communications. Other standards development such as STANAG 5066 provides for error free data communications through the use of ARQ protocols.
CB radios operate in the higher portion of the range (around 27 MHz), as do some studio-to-transmitter (STL) radio links. Some modes of communication, such as continuous wave morse code transmissions (especially by amateur radio operators) and single sideband voice transmissions are more common in the HF range than on other frequencies, because of their bandwidth-conserving nature, but broadband modes, such as TV transmissions, are generally prohibited by HF's relatively small chunk of electromagnetic spectrum space.
Noise, especially man-made interference from electronic devices, tends to have a great effect on the HF bands. In recent years, concerns have risen among certain users of the HF spectrum over "broadband over power lines" (BPL) Internet access, which is believed to have an almost destructive effect on HF communications. This is due to the frequencies on which BPL operates (typically corresponding with the HF band) and the tendency for the BPL "signal" to leak from power lines. Some BPL providers have installed "notch filters" to block out certain portions of the spectrum (namely the amateur radio bands), but a great amount of controversy over the deployment of this access method remains.
Some radio frequency identification (RFID) tags utilize HF. These tags are commonly known as HFID's or HighFID's (High Frequency Identification).

References

  1. ^ Paul Harden (2005). "Solar Activity & HF Propagation". QRP Amateur Radio Club International. http://www.qrparci.org/content/view/58/118/. Retrieved 2009-02-22.
  2. ^ "Amateur Radio Emergency Communication". American Radio Relay League, Inc.. 2008. http://www.arrl.org/pio/emergen1.html. Retrieved 2009-02-22.

Further reading

  • Maslin, N.M. "HF Communications - A Systems Approach". ISBN 0-273-02675-5, Taylor & Francis Ltd, 1987
  • Johnson, E.E., et al., "Advanced High-Frequency Radio Communications". ISBN 0-89006-815-1, Artech House, 1997
  • V. Narayanamurti, et al., "Selective Transmission of High-Frequency Phonons by a Superlattice: The "Dielectric" Phonon Filter". Phys. Rev. Lett. 43, 2012–2016 (Issue 27 – 31 December 1979).
  • Boulos-Paul Bejjani, et al., "Transient Acute Depression Induced by High-Frequency Deep-Brain Stimulation". New England Journal of Medicine, Volume 340:1476-1480 May 13, 1999 Number 19. Massachusetts Medical Society.
  • H. C. Liu, "Analytical model of high-frequency resonant tunneling: The first-order ac current response". Phys. Rev. B 43, 12538–12548 (Issue 15 – 15 May 1991).
  • Sipila, M., et al., "High-frequency periodic time-domain waveform measurement system". IEEE Transactions on Microwave Theory and Techniques, Volume 36, Issue 10, pg. 1397-1405, Oct 1988. ISSN 0018-9480 INSPEC 3291255 DOI 10.1109/22.6087
  • Morched, A., et al., "A high frequency transformer model for the EMTP". IEEE Transactions on Power Delivery, Volume 8, Issue 3, pg. 1615-1626, Jul 1993. ISSN 0885-8977 INSPEC 4581865 DOI 10.1109/61.252688

External links


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Amateur (Ham) Radio

Amateur radio

From Wikipedia, the free encyclopedia



A modern HF transceiver with spectrum analyzer and DSP capabilities

An amateur radio antenna tower
"Ham radio" redirects here. For other uses, see Ham radio (disambiguation).
Amateur radio, often called ham radio, is both a hobby and a service in which participants, called "hams," use various types of radio communications equipment to communicate with other radio amateurs for public service, recreation and self-training.[1]
Amateur radio operators enjoy personal (and often worldwide) wireless communications with each other and are able to support their communities with emergency and disaster communications if necessary, while increasing their personal knowledge of electronics and radio theory. An estimated six million people throughout the world are regularly involved with amateur radio.[2]
The term "amateur" reflects the principle that Amateur Radio and its skilled operators are committed to helping communities without financial compensation; whereas Commercial Radio operates purely for profit.

History


Though its origins can be traced to at least the late 1800s, amateur radio, as practiced today, did not begin until the early 1900s. The first listing of amateur radio stations is contained in the First Annual Official Wireless Blue Book of the Wireless Association of America in 1909.[3] This first radio callbook lists wireless telegraph stations in Canada and the United States, including eighty-nine amateur radio stations. As with radio in general, the birth of amateur radio was strongly associated with various amateur experimenters and hobbyists. Throughout its history, amateur radio enthusiasts have made significant contributions to science, engineering, industry, and social services. Research by amateur radio operators has founded new industries[4], built economies[5], empowered nations[6], and saved lives[7] in times of emergency.

Activities and practices

Specialized Interests and modes
While many hams simply enjoy talking to friends, others pursue a wide variety of specialized interests.
Amateur Radio operators use various modes of transmission to communicate. Voice transmissions are most common, with some, such as frequency modulation (FM) offering high quality audio, and others, such as single sideband (SSB) offering more reliable communications, often over long distance, when signals are marginal and bandwidth is restricted, at the sacrifice of audio quality.
Radiotelegraphy using Morse code (also known as "CW" from "continuous wave") is an activity dating to the earliest days of radio. It is the wireless extension of land line (wire based) telegraphy developed by Samuel Morse and was the predominant real time long-distance communication method of the 19th century. Though computer-based (digital) modes and methods have largely replaced CW for commercial and military applications, many amateur radio operators still enjoy using the CW mode, particularly on the shortwave bands and for experimental work such as earth-moon-earth communication, with its inherent signal-to-noise ratio advantages. Morse, using internationally agreed message encodings such as the Q code, enables communication between amateurs who speak different languages. It is also popular with homebrewers as CW-only transmitters are simpler to construct. A similar "legacy" mode popular with home constructors is amplitude modulation (AM), pursued by many vintage amateur radio enthusiasts and aficionados of vacuum tube technology.
For many years, demonstrating a proficiency in Morse code was a requirement to obtain amateur licenses for the high frequency bands (frequencies below 30 MHz), but following changes in international regulations in 2003, countries are no longer required to demand proficiency.[8] As an example, the United States Federal Communications Commission phased out this requirement for all license classes on February 23, 2007.[9][10]
Modern personal computers have encouraged the use of digital modes such as radioteletype (RTTY), which previously required cumbersome mechanical equipment.[11] Hams led the development of packet radio, which has employed protocols such as TCP/IP since the 1970s. Specialized digital modes such as PSK31 allow real-time, low-power communications on the shortwave bands. Echolink using Voice over IP technology has enabled amateurs to communicate through local Internet-connected repeaters and radio nodes[12], while IRLP has allowed the linking of repeaters to provide greater coverage area. Automatic link establishment (ALE) has enabled continuous amateur radio networks to operate on the high frequency bands with global coverage. Other modes, such as FSK441 using software such as WSJT, are used for weak signal modes including meteor scatter and moonbounce communications.
Fast scan amateur television has gained popularity as hobbyists adapt inexpensive consumer video electronics like camcorders and video cards in home computers. Because of the wide bandwidth and stable signals required, amateur television is typically found in the 70 cm (420 MHz–450 MHz) frequency range, though there is also limited use on 33 cm (902 MHz–928 MHz), 23 cm (1240 MHz–1300 MHz) and higher. These requirements also effectively limit the signal range to between 20 and 60 miles (30 km–100 km), however, the use of linked repeater systems can allow transmissions across hundreds of miles.[13]
These repeaters, or automated relay stations, are used on VHF and higher frequencies to increase signal range. Repeaters are usually located on top of a mountain, hill or tall building, and allow operators to communicate over hundreds of square miles using a low power hand-held transceiver. Repeaters can also be linked together by use of other amateur radio bands, landline or the Internet.
Communication satellites called OSCARs (Orbiting Satellite Carrying Amateur Radio) can be accessed, some using a hand-held transceiver (HT) with a factory "rubber duck" antenna. Hams also use the moon, the aurora borealis, and the ionized trails of meteors as reflectors of radio waves.[14] Hams are also often able to make contact with the International Space Station (ISS),[15] as many astronauts and cosmonauts are licensed as Amateur Radio Operators.[16]
Amateur radio operators use their amateur radio station to make contacts with individual hams as well as participating in round table discussion groups or "rag chew sessions" on the air. Some join in regularly scheduled on-air meetings with other amateur radio operators, called "Nets" (as in "networks") which are moderated by a station referred to as "Net Control".[17] Nets can allow operators to learn procedures for emergencies, be an informal round table or be topical, covering specific interests shared by a group.

Licensing


A handheld VHF/UHF transceiver
Main article: Amateur radio license
In all countries, amateur radio operators are required to pass a licensing exam displaying knowledge and understanding of key concepts[18]. In response, hams are granted operating privileges in larger segments of the radio frequency spectrum using a wide variety of communication techniques with higher power levels permitted. This practice is in contrast to unlicensed personal radio services such as CB radio, Multi-Use Radio Service, or Family Radio Service/PMR446 that require type-approved equipment restricted in frequency range and power.
In many countries, amateur licensing is a routine civil administrative matter. Amateurs are required to pass an examination to demonstrate technical knowledge, operating competence and awareness of legal and regulatory requirements in order to avoid interference with other amateurs and other radio services. There are often a series of exams available, each progressively more challenging and granting more privileges in terms of frequency availability, power output, permitted experimentation, and in some countries, distinctive callsigns. Some countries such as the United Kingdom and Australia have begun requiring a practical training course in addition to the written exams in order to obtain a beginner's license, called a Foundation License.
Amateur radio licensing in the United States serves as an example of the way some countries award different levels of amateur radio licenses based on technical knowledge. Three sequential levels of licensing exams (Technician Class, General Class and Amateur Extra Class) are currently offered, which allow operators who pass them access to larger portions of the Amateur Radio spectrum and more desirable callsigns.

Newcomers

Many people start their involvement in amateur radio by finding a local club. Clubs often provide information about licensing, local operating practices and technical advice. Newcomers also often study independently by purchasing books or other materials, sometimes with the help of a mentor, teacher or friend. Established amateurs who help newcomers are often referred to as "Elmers" within the ham community.[19][20] In addition, many countries have national amateur radio societies which encourage newcomers and work with government communications regulation authorities for the benefit of all radio amateurs. The oldest of these societies is the Wireless Institute of Australia, formed in 1910; other notable societies are the Radio Society of Great Britain, the American Radio Relay League, Radio Amateurs of Canada, the New Zealand Association of Radio Transmitters and South African Radio League. (See Category:Amateur radio organizations)

Callsigns

Upon licensing, a radio amateur's national government issues a unique callsign to the radio amateur. The holder of a callsign uses it on the air to legally identify the operator or station during any and all radio communication.[21] In certain jurisdictions, an operator may also select a "vanity" callsign although these must also conform to the issuing government's allocation and structure used for Amateur Radio callsigns.[22] Some jurisdictions, such as the U.S., require that a fee be paid to obtain such a vanity callsign; in others, such as the UK, a fee is not required and the vanity callsign may be selected when the license is applied for.
Callsign structure as prescribed by the ITU, consists of three parts which break down as follows, using the callsign ZS1NAT as an example:
  1. ZS – Shows the country from which the callsign originates and may also indicate the license class. (This callsign is licensed in South Africa, and is CEPT Class 1).
  2. 1 – Gives the subdivision of the country or territory indicated in the first part (this one refers to the Western Cape).
  3. NAT – The final part is unique to the holder of the license, identifying that person specifically.
Many countries do not follow the ITU convention for the numeral. In the United Kingdom the calls G2xxx, G3xxx, and G6xxx may be issued to stations, these are Full Licence Holders. Additional licences are granted in respect of Foundation Licensees M3xxx and M6xxx, Intermediate Licencees 2E1xxx and 2E0xxx and Full Licence Holders M0xxx and M1xxx. In the United States, the numeral indicates the geographical district the holder resided in when the license was issued. Prior to 1978, US hams were required to obtain a new callsign if they moved out of their geographic district.
Also, for smaller entities, a numeral may be part of the country identification. For example, VP2xxx is in the British West Indies (subdivided into VP2Exx Anguilla, VP2Mxx Montserrat, and VP2Vxx British Virgin Islands), VP5xxx is in the Turks and Caicos Islands, VP6xxx is on Pitcairn Island, VP8xxx is in the Falklands, and VP9xxx is in Bermuda.
Anybody can look up who a specific United States callsign belongs to using the FCC's license search database. Information may be available for other jurisdictions on websites such as Callbook.

Privileges

Unlike other RF spectrum users, radio amateurs may build or modify transmitting equipment for their own use within the amateur spectrum without the need to obtain government certification of the equipment.[23][24] Licensed amateurs can also use any frequency in their bands (rather than being allocated fixed frequencies or channels) and can operate medium to high-powered equipment on a wide range of frequencies[25] so long as they meet certain technical parameters including occupied bandwidth, power, and maintenance of spurious emission.
As noted, radio amateurs have access to frequency allocations throughout the RF spectrum, enabling choice of frequency to enable effective communication whether across a city, a region, a country, a continent or the whole world regardless of season or time day or night. The shortwave bands, or HF, can allow worldwide communication, the VHF and UHF bands offer excellent regional communication, and the broad microwave bands have enough space, or bandwidth, for television (known as SSTV and FSTV) transmissions and high-speed data networks.

The international symbol for amateur radio, included in the logos of many IARU member societies. The diamond holds a circuit diagram featuring components common to every radio: an antenna, inductor and ground.
Although allowable power levels are moderate by commercial standards, they are sufficient to enable global communication. Power limits vary from country to country and between license classes within a country. For example, the power limits for the highest available license classes in a few selected countries are: 2.25 kW in Canada, was 2 kW in the former Yugoslavia, 1.5 kW in the United States, 1 kW in Belgium and Switzerland, 750 W in Germany, 500 W in Italy, 400 W in Australia, India and the United Kingdom, and 150 W in Oman. Lower license classes usually have lower power limits; for example, the lowest license class in the UK has a limit of just 10 W. Amateur radio operators are encouraged both by regulations and tradition of respectful use of the spectrum to use as little power as possible to accomplish the communication[26].
When traveling abroad, visiting amateur operators must follow the rules of the country in which they wish to operate. Some countries have reciprocal international operating agreements allowing hams from other countries to operate within their borders with just their home country license. Other host countries require that the visiting ham apply for a formal permit, or even a new host country-issued license, in advance.
Many jurisdictions issue specialty vehicle registration plates to amateur radio operators who provide proof of an amateur radio license.[27][28] The fees for application and renewal are usually less than standard plates.[27][29]

Band plans and frequency allocations

Main article: Amateur radio frequency allocations
The International Telecommunication Union (ITU) governs the allocation of communications frequencies worldwide, with participation by each nation's communications regulation authority. National communications regulators have some liberty to restrict access to these frequencies or to award additional allocations as long as radio services in other countries do not suffer interference. In some countries, specific emission types are restricted to certain parts of the radio spectrum, and in most other countries, International Amateur Radio Union (IARU) member societies adopt voluntary plans to ensure the most effective use of spectrum.
In a few cases, a national telecommunication agency may also allow hams to use frequencies outside of the internationally allocated amateur radio bands. In Trinidad and Tobago, hams are allowed to use a repeater which is located on 148.800 MHz. This repeater is used and maintained by the National Emergency Management Agency (NEMA), but may be used by radio amateurs in times of emergency or during normal times to test their capability and conduct emergency drills. This repeater can also be used by non-ham NEMA staff and REACT members. In Australia and New Zealand ham operators are authorized to use one of the UHF TV channels. In the U.S., in cases of emergency, amateur radio operators may use any frequency including those of other radio services such as police and fire communications and the Alaska statewide emergency frequency of 5167.5 kHz.
Similarly, amateurs in the United States may apply to be registered with the Military Affiliate Radio System (MARS). Once approved and trained, these amateurs also operate on US Government Military frequencies to provide contingency communications and morale message traffic support to the military services.

References

Cited References
  1. ^ Lau, Mary E (2006-05-23). "Ham Radio Frequently Asked Questions". ARRL.org. http://www.arrl.org/FandES/ead/hamfaq.html. Retrieved 2007-08-25.
  2. ^ Silver, H Ward (2004-04-23). Amateur Radio for Dummies. Indianapolis: Wiley Publishing. ISBN 0764559877. OCLC 55092631.
  3. ^ Gernsback, H (May 1909) (PDF). First Annual Official Wireless Blue Book of the Wireless Association of America. New York: Modern Electrics Publication. http://www.seas.upenn.edu/~uparc/documents/First%20Annual%20Official%20Wireless%20Blue%20Book%20-%201909.pdf. Retrieved 2009-06-19.
  4. ^ http://www.bliley.net/XTAL/Industry-Hams.html THE INFLUENCE OF AMATEUR RADIO ON THE DEVELOPMENT OF THE COMMERCIAL MARKET FOR QUARTZ PIEZOELECTRIC RESONATORS IN THE UNITED STATES. By Patrick R. J. Brown, Hewlett Packard Company, Spokane Division
  5. ^ people.smu.edu/arc/ Inventor of IC "chip", Nobel Prize Winner Jack S. Kilby Credits Amateur Radio for His Start in Electronics.
  6. ^ www.ari.vt.edu/internet/Impression/ICT.pdf Role of Amateur Radio in Development Communication of Bangladesh. Information & Communication Technology for Development. By Bazlur Rahman
  7. ^ http://www.arrl.org/news/stories/2004/12/29/100/?nc=1 Amateur Radio "Saved Lives" in South Asia ARRL.org
  8. ^ "FCC Report and Order 06-178A1" (PDF). Federal Communications Commission. 2006-12-19. pp. p. 7. http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-06-178A1.pdf. Retrieved 2007-05-16.
  9. ^ Federal Communications Commission (2007-01-24). "47 CFR Part 97" (PDF). Federal Register (Washington, D.C.: Government Printing Office) 72 (15): 3081–3082. http://edocket.access.gpo.gov/2007/pdf/E7-729.pdf. Retrieved 2007-12-18.
  10. ^ "FCC to Drop Morse Testing for All Amateur License Classes". ARRL.org. 2006-12-19. http://www2.arrl.org/news/stories/2006/12/15/104/?nc=1. Retrieved 2007-05-16.
  11. ^ Galbraith, E Art (2003-08-23). "KH6BB and "Mighty Mo," the Battleship Missouri". ARRL.org. http://www2.arrl.org/news/features/2003/08/27/1/?nc=1. Retrieved 2007-01-10.
  12. ^ http://communication.howstuffworks.com/ip-telephony10.htm
  13. ^ Taggart, Ralph E (April 1993). "An Introduction to Amateur Television" (PDF). QST via ARRL.org: 19–23. http://www.arrl.org/tis/info/pdf/49319.pdf. Retrieved 2007-06-02.
  14. ^ Taylor, Joe (December 2001). "WSJT: New Software for VHF Meteor-Scatter Communication" (PDF). QST via ARRL.org: pp. 36—41. http://www.arrl.org/tis/info/pdf/0112036.pdf. Retrieved 2007-01-11.
  15. ^ "ARISS: Amateur Radio on the International Space Station". ARRL.org. http://www.arrl.org/ARISS/. Retrieved 2007-01-10.
  16. ^ Jurrens, Gerald. "Astronaut (and Former Astronaut) Hams". gjurrens at Tellurian.com. http://users.tellurian.com/gjurrens/astrohams.html. Retrieved 2007-01-10.
  17. ^ Haag, Jerry. "Principles of Amateur Radio Net Control". SCC-AREA-RACES.org. http://www.scc-ares-races.org/mtnview/principles-of-net-control.html. Retrieved 2007-01-10.
  18. ^ http://www.itu.int/rec/R-REC-M.1544/e International Telecommunications Union, Minimum Qualifications For Radio Amateurs
  19. ^ http://www.arrl.org/FandES/field/club/mentor/ ARRL Web, ARRL Mentor Program
  20. ^ The ARRL Handbook for Radio Communications 2007: The Comprehensive RF Engineering Reference by Mark J. Wilson, Dana G. Reed, American Radio Relay League. Published by American Radio Relay League, 2006. Original from the University of Michigan. Digitized Dec 21, 2007. ISBN 0872599760, 9780872599765
  21. ^ "Amateur Radio (Intermediate) Licence (A) or (B) Terms, Provisions and Limitations Booklet BR68/I". Ofcom.org.uk. http://www.ofcom.org.uk/static/archive/ra/publication/ra_info/br68i/br68i.htm. Retrieved 2007-06-02.
  22. ^ "Common Filing Task: Obtaining Vanity Call Sign". FCC.gov. http://wireless.fcc.gov/services/index.htm?job=cft&id=amateur&page=cft_get_call_sign. Retrieved 2007-06-02.
  23. ^ www.ofta.gov.hk/en/rae/rae0101E_F.pdf OFTA Amateurs are free to choose any radio equipment designed for the amateur service. Amateurs may also design and build their own equipment provided that the requirements and limitations specified in the licence and Schedules thereto are complied with.
  24. ^ http://wireless.fcc.gov/services/index.htm?job=about&id=amateur FCC.gov, About Amateur Stations They design, construct, modify, and repair their stations. The FCC equipment authorization program does not generally apply to amateur station transmitters.
  25. ^ http://vkfaq.ampr.org/faq2lic.html Australian Radio Amateur FAQ
  26. ^ "FCC Transmitter power standards". ARRL.org. http://www.arrl.org/FandES/field/regulations/news/part97/d-305.html#313. Retrieved 2008-05-26.
  27. ^ a b "ARRL Web:Amateur Radio License Plate Fees". http://www.arrl.org/FandES/field/regulations/local/plates.html. Retrieved 2008-12-04.
  28. ^ "Ham Radio Callsign License Plates (Canada)". http://plates.hfradio.net/plate1.html. Retrieved 2008-12-04.
  29. ^ "ICBC - HAM radio plates". http://www.icbc.com/registration/reg_spec_lic_plates_ham.asp. Retrieved 2008-12-03.
General References
  • Bergquist, Carl J (2001-05-01). Ham Radio Operator's Guide (2nd ed.). Indianapolis: Prompt Publications. ISBN 0-7906-1238-0.
  • Dennison, Mike and Chris Lorek (eds.) (June 2005). Radio Communication Handbook (8th ed.). Potters Bar, Hertfordshire, England: Radio Society of Great Britain. ISBN 1-90508608-3.
  • Poole, Ian D (2001-10-31). HF Amateur Radio. Potters Bar, Hertfordshire, England: Radio Society of Great Britain. ISBN 1-872309-75-5.
  • Rohde, Ulrich L; Whitaker, Jerry C (2001). Communications Receivers: DSP, Software Radios, and Design (3rd ed.). New York City: McGraw-Hill. ISBN 0-07-136121-9.
  • Straw, R Dean (ed.) (October 2005). The ARRL Handbook for Radio Communications 2006 (83rd ed.). Newington, CT: American Radio Relay League. ISBN 0-87259-949-3.

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