Domain: arrl.org
Stories and comments across the archive that link to arrl.org.
Comments · 765
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Re:Whoa there Nelly!
Not only does the US have FiOS now, it doesn't have the destruction of the HAM radio spectrum floor because of BPL noise and interference.
Given, there have been tests in the US and as the ARRL so correctly points out it screws everything up. "Oh it can be filtered", the corporate fascists argue, yet, go visit ARRL and see what they say.
One quote from the article, "Just as generations of bankers have known that it's a bad idea to lend money to people who can't pay it back, generations of electrical engineers have known that -- unless you want it to radiate -- it's a bad idea to put radio frequency energy on an unshielded, unbalanced conductor."
There you have it, our FCC run by fascists instead of engineers.
(BONUS POINTS: What ever happened to the FCC mission statement?) -
Re:It'll never happen
Your remarks about limited bandwidth are patently false. See the American Radio Relay League http://www.arrl.org/ and its discussion on BPL, and on their Federal Lawsuit against the FCC for promoting the wide bandwidth BPL. There are systems that have been developed, for example, at Motorola, that reduce interference in the 1Mhz to 30Mhz range, but no one seems to want to use them or care, despite violating FCC regulations that say that unlicensed devices cannot interfere with properly licensed ham radio and public service communication stations.
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Re:BPL screws up shortwave radio
I, as well as many others I'm sure, have submitted numerous news stories to
/. about the flagrant bias toward BPL and the facts being covered up by the FCC. Oddly, none ever get posted. Mod me troll, I don't care; I think it's obvious what side of the issue the /. mods are on. -
Re:Bad Idea
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Re:The shutdown of future learningPatently false. Even as Amateur Radio charges into the digital radio future, it will almost certainly still have analog transmission modes. We are allowed (and encouraged) to make our own equipment and to provide emergency communications and advance the radio art, which are part of our justification for existence. Since digital modes will take a long time to become de rigueur around the world, AM, FM, and SSB will be around for a long time.
There are still tons of operators that run full double sideband, full carrier AM - although their signals are not the most spectrum-efficient on the air, their audio is usually great-sounding. -
Re:How is this different than what hams have done?
The ARRL Antenna Manual is probably one of the longest-standing references for antenna and feedline theory.
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Re:Time for the Electric Company to Jump in for Re
The problem with broadband over powerlines is that it wreaks havok on several of the HAM bands in the US. See http://www.arrl.org/tis/info/HTML/plc/bpl-deployment.html
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Take a look at ARRL's take on this report
The ARRL posted a story about this NTIA report. They took a good look at the parts dealing with BPL (broadband over power lines). It is definitely worth reading.
(ARRL is the American Radio Relay League - kind of like a lobbying organization for amateur radio)
http://www.arrl.org/news/stories/2008/02/01/101/?nc=1
ARRL has been watching BPL very closely as many of the BPL operations have been polluting the radio spectrum. BPL so far has been a huge failure.
They note that NTIA doesn't seem to know how many BPL customers there are. They estimate there are 200,000. Their projections for future usage are laughable. From the ARRL story, here are the FCC numbers along with an interesting comment.
"The FCC's data showing fewer than 5000 BPL customers -- a number that dropped in the six-month period covered by the report -- are taken from forms that service providers are required to submit"
In other words, we require you to provide the data. But, we will conveniently forget that if the numbers aren't flattering. Add to that an outdated map of BPL operations in the states. Many no longer exist. The BPL interests must have a heck of a lobby.
We need a real broadband strategy. BPL has no place in it. Neither does this absolutely silly and useless NTIA report. -
Plenty of FREE airwaves out there...(USA centric)
All you have to do is pass a wimpy test and get your ham license. No more Morse code.
Here's what you will get to play with upon passing your exams.
Here is a nice, slightly dated(2003) frequency allocation chart showing who's got what and where. -
Re:Mmm.. BBS over HAM
As I recall there was a lot of opposition to BPL because it interferes with the HAM radio spectrum.
Acutally, it interferes with the entire radio spectrum. When the plan was first announced, the military was one of the most vocal opponents of the plan. I don't know if they still are or not, as I haven't heard much about their opinion lately.
The ARRL, a sorta-NRA of ham radio, has recently filed a case with a federal court over BPL. The gripe is that the FCC relaxed their rules regarding Part 15 emissions (radiations from unlicensed transmitters) to allow BPL to operate.
Here's a page at the ARRL about BPL: http://www.arrl.org/tis/info/HTML/plc/
Here's a couple YouTube videos demonstrating the type of RF garbage these things emit all over the RF spectrum:
http://youtube.com/watch?v=HDSQJ8zOnhQ
http://youtube.com/watch?v=pdcY0Eetvsw -
Instruments of Amplificationtake that homebrew computer club! i'll bet none of those guys ever made their own transistors! Making integrated circuits (ICs) might be a better analogy.
Haven't read it but this book claims to show you how to make your own vacuum tubes AND transistors! -
Re:"steamed hams"?
Yeah, that kinda makes a 10m contest pointless, doesn't it? I worked hundreds of DX stations with a 25W mobile station in 1989 or '90. Those were hot sunspot years.
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FEMA & ARRL
The ARRL has an official agreement with FEMA to raise awareness, provide training, etc. You can read the actual agreement here: http://www.arrl.org/FandES/field/mou/FEMA-ARRL-SOA1.pdf. It didn't exist until 2003, however. I don't know if anything was in place prior to that, but my guess would be that there was not.
As you might expect, Amateur Radio's direct involvement with organizations like FEMA, as well as state, county and city agencies across the country, became much more formalized after 9/11. And even more formalized still after Katrina. For example, the ARRL now offers certification training for hams, and many local agencies require at least the first level of that training for hams to volunteer as communicators in their areas.
In some ways, Katrina had a bigger impact on all of this than 9/11. One of the things people realized after Katrina is that you can't necessarily rely on the local hams to come to the aid of the area -- they're too busy taking care of their own families! And unlike 9/11, which was localized to a few specific sites, Katrina covered a vast area. So help had to be called in from neighboring states, etc., and then the problem became figuring out who was there, who was qualified to do what, etc. The volunteers coming in didn't necessarily know the areas they were volunteering in either, and there weren't always enough local volunteers to help them figure it out, so coordination became a challenge.
The training classes that are being offered now -- both from the ARRL for communications related training, and the CERT (Community Emergency Response Team) programs that are offered by local agencies -- are aiming to solve not only the training of prospective volunteers, but also to keep track of who's available and what their expertise might be.
(By the way, the CERT training is aimed at anyone that wants to help... it isn't a ham radio certification, but a generic volunteer certification. I live in San Jose, CA, and you can't even volunteer for most public events (a parade or what have you) if you don't have basic CERT training and a City ID badge.)
I've been a ham for over 30 years, and I have to admit that all this formalized training is taking some getting used to; I'm used to just grabbing my gear and heading out the door when someone needs assistance. But I recognize that it's the right thing to do. And if hams are to continue to provide support when needed, we have to keep up with the times... even OM's (ham-speak for "Old Men") like me.
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Re:Ham's day is over, probably
If you're only "reasonably certain" of something, you might want to Google a bit. According to the ARRL, the reasonable accommodation rule applies to ham antennas too.
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Re:Ham's day is over, probably
Currently there are no licenses that require Morse code. PDF of announcement.
Got my Technician just last month. My grandpa was speechless (and not beceause he replied in Morse).
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Re:Ham's day is over, probably
Just to clarify, in the USA as of 23 February 2007, there is no Morse code exam requirement for any of the US amateur radio license classes. All that is required is to pass a written exam. Additionally, a 'no code' Technician license has been around since 1991.
http://www.arrl.org/news/stories/2007/01/24/100/?nc=1 -
Re:Thanks, guys!I'm pretty sure that among the long list of "served agencies" FEMA appears. I'm pretty also impressed by other agencies embrace of amateur radio- the elaborate radio room set up both at the National Weather Service office here in S.E. Wisconsin and at the downtown Red Cross building. In both cases, the staff of the served agency can't use the equipment. It just sits there until an emergency net is activated and the hams come a-runnin'. Of course there's drills, training, and other activity to keep any dust from settling on the gear.
Local ARES and RACES groups are often the core of the volunteer organizations locally/regionally. The Amateur Radio Emergency Service (ARES) consists of licensed amateurs who have voluntarily registered their qualifications and equipment for communications duty in the public service when disaster strikes.
Home page: http://www.ares.org/
Nice summary: http://www.arrl.org/FandES/field/pscm/sec1-ch1.htmlRACES (Radio Amateur Civil Emergency Service) is less active in my area and I think I heard that they were combining some activities with the local ARES folks. Administered by local, county and state emergency management agencies, and supported by the Federal Emergency Management Agency (FEMA)
http://www.races.net/And as I say whenever I get the chance, it has never been easier to be a ham. All morse code requirements have been removed from the licensing process, and anyone that can study for a test can pass the exam. Once that's done, there's a huge core of groups out there to help you get started. There's also groups that meet for training for the exams, if you like that idea better than studying on your own.
Tom, N9QQB, member of the Milwaukee 145.130 repeater, 1000 watts of RF goodness at your fingertips. IRLP node number 5590 - call us from anywhere in the world via internet link.
73 de N9QQB
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Re:Thanks, guys!
Yes DHS has a program. You can read about it here.
http://www.arrl.org/news/stories/2006/10/04/100/?nc=1 -
Re:Ham's day is over, probably
The Morse Code requirement was dropped for all classes of amateur radio license in the U.S. in February of this year:
http://www.arrl.org/news/stories/2007/01/24/100/?nc=1
It had been a requirement imposed by international treaties until a few years ago. The FCC kept this archaic requirement for a few years longer. The U.S. military dropped Morse Code a few years ago as well.
I agree, though, about the crotchety old farts. I had an Advanced Class license when I was in high school and college, but let it drop. A few years ago I bought a scanner and a cheap digital SW receiver to see if I might want to re-license. Listening to the local VHF repeaters was a hoot, listening to the geezers (OK, I guess they are my age...) get twisted in a knot.
While I never was able to copy the 25WPM needed for the Extra license, I still copy in my head when watching WWII war movies. They can be pretty amusing. Yes, they are usually sending real Morse code, but it isn't always in context. :)
While tuning-around with my recent toys, I had a brief fascination with QPSK, a very narrow-band digital technique used on shortwave frequencies. Typically done by running the audio output of your receiver into a computer sound card and running a DSP application on your PC. The PC applications are able to copy several conversations from around the world at once out of the slice of spectrum pumped into the sound card. Kinda like IRC on (slow) steroids.
While disaster communications is not the be all and end-all for amateur radio (it's just one of the justifications for it's existence - experimentation is another - some of the first communication satellites were designed and constructed by hams and launched as "ballast" by the U.S. Air Force and then NASA. Amsat Oscar I was launched in 1961.) and it's not something I've ever been involved in, my hat is off to those who've helped out in the NW floods. Most of the time, these people wait around and train for disasters that never happen, and then have to deal with officials who keep them on a long leash. In this case, they really were needed, and thankfully the officials weren't obstructive, and the training and innovative spirit of these hams appears to have been put to good use, and has been truly helpful and perhaps life-saving.
My favorite quote from my mother: "What's all this about radio? Television is the thing now!" If not for ham radio, I'd probably not have wire-wrapped that 8008 computer, and would probably be another out-of-work real estate agent.
(Ex-WB8DBN - "Detroit's Bad Novice", from my WN8 days...) -
Good job!
It's good to see some publicity about amateur radio.
Pretty easy to get your license, too. About a week's worth of studying will get you on the air. The ARRL (American Radio Relay League) has a ton of info about getting licensed.
It's exciting that you can IM someone through the internet and have it appear in a couple milliseconds........but how about sending a transmission through the air to someone on the other side of the world at the speed of light using something half the size of your laptop and an antenna as long as that crazy cat-5 wire you have stretched across 3 rooms?
73 de KB3OOJ -
Re:Ham's day is over, probablylicensing was more decentralised (why not have individual ham radio non-profits do the licensing?)
You mean something like this?
From that page:# The ARRL VEC program began in July 1984 (After the FCC stopped testing at FCC Field Offices, they created the VEC system in 1983). ARRL/VEC has over 20 years of Service to Radio Amateurs, operating as a knowledgeable information source for a wide-range of licensing issues.
# Today, the ARRL VEC is the largest of the 14 VECs, representing more than 65% of all exams given (at one point there were over 25 VECs). -
Entirely feasible
Entirely feasible, the Sputnik was basically a low power (QRP) transmitter. AFAIK it had no other payload. Ham radio operators have been making these for years:
http://www.arrl.org/tis/info/qrpprojs.html
It did beep faster/slower as temperatures rose/fell, I think, which you could basically implement using normal temperature variations in off the shelf resistors and capacitors. -
Re:Sum it up for me
Try exceptionally poor.
At and near the maximum of a solar cycle, the increased number of sunspots causes more ultraviolet radiation to impinge on the atmosphere. This results in significantly more F region ionization, allowing the ionosphere to refract higher frequencies (15, 12, 10, and even 6 meters) back to Earth for DX contacts. At and near the minimum between solar cycles, the number of sunspots is so low that higher frequencies go through the ionosphere into space. Commensurate with solar minimum, though, is less absorption and a more stable ionosphere, resulting in the best propagation on the lower frequencies (160 and 80 meters). Thus, in general, high SSNs are best for high-frequency propagation, and low SSNs are best for low-frequency propagation. (source)
Without the ionization provided by the sunspots, there is little to no reflection of radio waves by the ionosphere, and hence little to no propagation. -
Re:Ham radio has its day in court
See www.arrl.org for details
For those who want a direct link to the relevant section about BPL, here it is... http://www.arrl.org/tis/info/HTML/plc/
73
W9QNY -
Re:This, my friends....
ARRL Chief Executive Officer David Sumner, K1ZZ expressed appreciation for Motorola's approach to the thorny issue of radio interference from BPL systems. In an effort to minimize interference, particularly to the Amateur Radio bands, Motorola designed its Powerline LV system in close cooperation with the League's technical staff, Sumner noted. A test stand Access BPL system was in operation briefly at ARRL Headquarters. Measurements and subjective listening tests on the ham bands showed that Powerline LV was Amateur Radio-friendly.
complete article here http://www.arrl.org/news/stories/2007/04/25/102/?nc=1 -
Re:Much more versatile than bullets...Yes a civilian 45 KW generator is a moderately sized package, but we are talking about a military system
A crowd control system does not need to be of a military style. Military hardware is designed to function on its own far away from support bases, and be serviced by soldiers with only basic education. Police systems do not go more than a few miles from the base, not going to be air{lifted,dropped}, won't see temperature extremes of deserts and arctic, and qualified technicians are available.
and don't forget that you have to have a dual oiling systems so the oil can be changed without shutting down the generator engine
There is no need to do that, the ray gun would be used for minutes, not for weeks. You are approaching this from design positions of a backup diesel generator of a military communications facility. This gizmo is nowhere close to that.
there could always be a nuke going off
Then there is no need to zap anyone with this toy - the people would be already thoroughly zapped with the gamma rays. We are talking about civil disturbance in a city, not a war with a nuclear superpower!
why would they sell a $5.00 dish when they can sell a $10,000.00 electronically steered phased array emitter?
It's cool, that's why
:-) Besides, no moving parts - good for reliability. Also, nobody sees where you are pointing it (though a radome would take care of that as well.) Mere $10K is not an issue, trucks with those weapons will be purchased by the government[s] and distributed to police just as candy. Politicians will be at each other's throats to get a piece of the action.I think you are also under-estimating the engineering required to generate the a 95 GHz signal at the required power-density
Well, it had been engineered already, however complex it might be. I personally stay away from any signals that are above a few GHz. That work requires a completely different mindset. But I know people who are obsessed with anything between 10 and 110 GHz, and some do very well in this.
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Re:Is there an "entry-level" for radio astronomy?
There's a nice picture of the historical entry into radio astronomy here.
A repurposed TV dish with a decent microwave receiver ought to do you pretty well. Just remember that radio astronomy happens one pixel at a time. -
This contradicts wikipediaWikipedia says that it was possible for amateur radio operators to receive data:
On March 31, 2006, the amateur radio operators from AMSAT Germany tracked and received data from Voyager 1 using the 20 m dish at Bochum with a long integration technique. Its data was checked and verified against data from the Deep Space Network station at Madrid, Spain. AMSAT-DL article in German; ARRL article in English. This is believed to be the first such tracking of Voyager.
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The original equipment probabily just works...
Communication with different equipment has been done. http://www.arrl.org/news/stories/2006/04/25/2/
Proof that it's not a problem to receive and decode. Transmit can't be any harder. But why "upgrade" it if they don't have to? The old equipment probably works just fine, so there is no incentive. -
Re:Pointless"employment history, past residences and any illegal drug use."
... have absolutely nothing to do with integrity and loyalty. Although I'm sure they can be used to discriminate against people who don't fit into a certain right-wing profile.It's all a bunch of unnecessary, intrusive crap.
I once worked for a railroad which, having gotten the "right" to test train crews after accidents, gradually extended the tests to random screening, then extended it farther to include other employees, including a woman who was a programmer in some department. She refused, got fired, took them to court and won. Big -- $485,042. http://www.art.net/~hopkins/Don/hemp/drug-testing
- dead.htmlThe American Red Cross recently instituted a triple background check for all volunteers. The ARRL (American Radio Relay League, a national organization which represents amateur radio operators' interests), published a writeup on the procedures associated with this check. http://www.arrl.org/announce/ARRL-ARC-bg-check.ht
m lThey did not take a position on the check; they merely recommended that any operators who wished to work with the ARC as emergency communicators in any kind of disaster read the terms extremely carefully to determine what they might be giving consent to.
Three key paragraphs from the article read:
Initially, the Red Cross' requirements included more than a criminal background check. Volunteers were also to be required to grant permission for the Red Cross' background investigation company to conduct a "credit check" and a "mode of living" check as well. Additionally, the Red Cross indicated that the only criminal background check they would accept would be from its own investigation company, "mybackgroundcheck.com."
On February 6, 2007, the Interim CEO and the National Chair of Volunteers of the Red Cross jointly announced that the policy had changed; (1) that only criminal background checks would be required of Red Cross volunteers; that credit checks would not be required except where separate permission was granted; and that mode of living checks would not be conducted on volunteers under any circumstances. However, the Red Cross' investigation company consent form still includes consent to the conduct of an "investigative consumer report." The Federal Trade Commission's definition of that term specifically includes "mode of living" checks and certain credit checks. The consent form that is required by the Red Cross, therefore, would permit both credit checks and mode of living checks, and not just criminal background checks. (2)
The new consent form used by "mybackgroundcheck.com" does not disclose to the person consenting to the search that he or she is in fact granting permission to have a credit check or mode of living check performed, but only makes reference to a "consumer investigative report" (3) without explaining it.Even if the ARC has backed down with respect to radio operators, the whole situation bespeaks a sheep-like acceptance of the idea that any invasion of privacy is justified if any connection, no matter how tenuous, can be made to "homeland security".
As a further example of the "mission creep" going on in Amerika, consider the following:
A few years back, there was a comm workers' strike around San Francisco. A few wires were cut in a couple of B-boxes. Sure enough, a local police agency loudly trumpeted that, "If we catch the perpetrators, we're gonna go for the four-year terrorism enhancement on whatever sentence they get."
Presumably he then put his stallion-like organ back in his pants and went back to work on the investigation.
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Sorry
Were you pictured in one of the first 3? I am not the type of guy to put a man down and not help him back up. Here is some advice to bring balance back to your life. First, switch to this. It is a compromise (and not my first choice) but it will give you time to implement my other advice. Second, buy and start using this and these. Third, stop eating these and talk to these people. It is not everything but it is a start. Just imagine yourself as cool as this guy. Read the DISCLAIMER
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Packet radio
Anyone remember packet radio? Packet Radio predates richochet by at least 10 years.
Packet radio, however, is hardly dead -- yeah, it's not exactly impressive to tell people "hey, I'm on the internet...over a radio" anymore, but there are still a lot of people doing some very impressive mobile stuff with APRS on VHF, or long-distance connectivity over HF.
Not long ago I went to a lecture by a ham who had spent some time down in Central America building an email system based on packet radio for some humanitarian workers down there. It was a pretty neat system -- VHF connections for the local links, and then an HF connection for the long haul back to the 'States. Given that the previous system had involved writing down messages and handing them to a ham operator to transmit via CW or SSB voice, even a few hundred baud (transmitting 24/7) was a pretty dramatic step up.
Only thing I didn't like about the system is that the software is all very Windows-centric, and some of the protocols they want to use are proprietary and/or patented (which I think is anathema to the entire concept of Amateur Radio and ought to be prohibited generally), sometimes requiring very expensive hardware modems. Not cool.
But anyway, if you haven't looked into packet in a while, and this goes not only for current hams but also anyone generally interested in computers or communications, it's definitely worth a look. Amateur radio in general is in the midst of a transition, where a lot of the people more resistant to change are dying off, and there's a lot of room for software hackers to get in on the ground floor and do some neat stuff. -
Sorry, been done before and topped...
Check out http://www.arrl.org/qst/worldabove/dxrecords.html for the Amateur Radio DX records. This was achieved long ago and at higher frequencies. Highest RF frequency used for a confirmed two-way communication was 403 GHz between WA1ZMS/4 (FM07ji) and W4WWQ/4 (FM07ji) on 21-Dec-2004 over a distance of 1.42 kilometers. Achieving a frequency is one thing but being able to use it is another.
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solar minimum
From the article:
"Last Updated: Tuesday, 6 July, 2004, 16:07 GMT 17:07 UK"
Come on guys, this is really old news.
If you want something more relevant, perhaps the fact that solar minimum still hasn't happened and the predictions are still being moved further out into the future. Last year at this time, solar minimum was expected in Sept. to Dec. 2006 now Feb. to May 2007 is the latest NOAA prediction.
http://www.arrl.org/news/stories/2007/04/06/100/?n c=1 -
Don't forget RF as an introduction to electronics
Don't forget RF as an introduction to electronics. If you want to know about series and parallel circuits and light bulbs, stick with DC and batteries. You mentioned capacitors and other components...understanding the behavior of RF circuits is part and parcel of understanding what a capacitor is for. Even digital designers need to know about RF circuits, so starting there can complement the understanding you probably already have of digital logic from programming.
Of course, I think the best way to learn about RF is through ham radio. Many hams are currently active in QRP (low-power or simple radio) operation, including design and construction. The circuits are small enough that you can breadboard them, and the people who design them often take great care to describe how things work, and how to hack them.
In fact, a formal course with a book written by Prof. David Rutledge of Cal Tech ("The Electronics of Radio") uses a simple ham radio transceiver as the basis for its introduction. The book at the kit are both still available.
Other simpler Kits and projects are available at
http://qrpkits.com/
http://www.njqrp.org/ (try their CD ROM of back issues of HomeBrewer magazine)
http://www.norcalqrp.org/ (which is having an informal meeting this Saturday in Sunnyvale, CA if you're in Silicon Valley)
http://4sqrp.com/
For online peer groups, you might try reading the archives of some of th Yahoo groups; there are about 4500 on amateur radio. Or try these:
http://mailman.qth.net/mailman/listinfo/qrp-l
http://qrp-l.org/
Getting a ham radio license can be an entre to a group of people who do this kind of thing and are used to helping each other. Now that the morse code requirement is lifted, you may find it easier to get a license. If you've gone through Forrest M Mimms III's books, you probably know about half of what you need already. See here for some roadmap info, or here for practice versions of the real tests, or here for a tutorial approach to the tests. -
Re:Pretty much the bible for EE's...
Yesss!!! The Art of Electronics is all you need to start with, in fact is "All You Need" (r). From there on just play yourself, experiment, read, burn capacitors, have fun!.
There are tons of more or less detailed projects in internet, ask Mr. Google
For a starter's microprocessor kit, I'll go fo Arduino it's cheap (22 euros plus shipping), all included (no need for a programer), and it's Open Source (well, that's slashdot, what else could you expect?;-).
If you're after audio look into DIY Audio & Video the cricket amp is a good starter project, and sounds nice (provided you do have an electric guitar). Or may be you prefer to assemble your own mp3 player or this other .
If you're after radio applications, ARRL is your place to go.
If you like robotics, the list is endless, try Kronos Robotics, DIY robotics (in UK), BEAM walkers , etc.
And for lots of ideas,as well of lot's of references, read Make , or just keep reading slashdot
;). -
Re:Thosands of times faster than electronics?
90%+ is possible for waveguides, and for open-wire feedline, but is usually lower for coaxial feedline.
VF is 1/sqrt(dielectric constant). Interestingly, the velocity itself is VF*c=1/sqrt(L*C) where c=speed of light in a vacuum, and L and C are the series inductance and shunt capacitance of the feedline, so those values are directly related to the velocity factor. Finally, given L and C we can calculate the characteristic impedance Z=sqrt(L/C).
The characteristic impedance of the coax is important to achieve maximum power transfer.
Another interesting thing nobody mentioned from the paper is that they say you can create an antenna by extending the center line out of the coax; presumably this is done with a 1/4 wavelength, though they specifically refer to this as matching to the impedance of free space, which we all know is 120*pi = ~377 Ohms. This number again is calculated by the sqrt(L/C) formula, but using L/m (magnetic permeability) and C/m (permittivity) which are both constants, so it's a little unfair.
You can do other fascinating calculations using transmission line equations. In fact, the paper says that the experimenters verified some of their findings by using larger scale components and microwave experiments.
So, if you're interested in the math behind, you can do it at home using standard coax and RF yourself, and get a flavor. Now that there's no more morse code test involved for getting a ham radio, it would be a good time to check out getting your ham license with just written tests of knowledge, and start doing experiments with practical results. -
Re:Shortwave
Ham radio builders and ham radio operators are very numerous and short wave will always be their domain.
http://www.arrl.org/ -
A few others
Some of these were pretty good, but I would have liked to see some better shots
... I personally found Top 10 Best Space Stories of 2006 more interesting, and some of the pics in Most Amazing Galactic Images ever were pretty good too.
Here's a couple other pics that I thought were top 10 material:
Man in space
Earth from Satellite -
Ham radio to celebrate 100 years of broadcasting
The ARRL is sponsoring an on-the-air celebration of the centennial of broadcasting. The Hello Radio campaign has been celebrating the upcoming event throughout most of 2006.
How many broadcasters will let this event go unremarked? That is sad indeed. -
Ham radio to celebrate 100 years of broadcasting
The ARRL is sponsoring an on-the-air celebration of the centennial of broadcasting. The Hello Radio campaign has been celebrating the upcoming event throughout most of 2006.
How many broadcasters will let this event go unremarked? That is sad indeed. -
Re:As a relatively new ham operator...
Woah, don't get me wrong. In my ideal world, the requirement would *still* be that an applicant submit the schematics of a proposed xmtr/rcvr, and subsequently, construct it themselves. I find articles such as http://www.arrl.org/tis/info/pdf/9708033.pdf very important. I'd go on, but it's quite late; please realize that I understand your sentiments. The problem is, we (the ham radio community) are losing potential members to the compsci/IT field at an alarming rate. Simply put, as much as I wish the situation was different, the ham community can't afford to be that exclusive anymore. Although I'm too young to have experienced it properly, I still regret the passing of a previous age, in the same way that I miss the age before Windows was standard (even though I've only really known the days of DOS, win2.11, and later.)
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Re:HAM radio license requirements
It's not that you have to know enough to build a radio. On the electronics front it's mainly knowledge about how basic circuits work, like oscillators and amplifiers. Much of the exam is on FCC rules and is simple memorization. Probably the most complicated thing you'd have to do is calculate the resonant frequency of a simple oscillator circuit or the proper length of an antenna for use on a given band, although I'm guessing a little here, since it's been fifteen years since I got my license. The license manuals teach you everything you need to know to pass the exam.
Look here for an amateur radio association in your area. The members are usually happy to help someone get their license. It's been said that every ham is responsible for bringing someone else into the hobby. -
Re:What the Morse?
It's probably worth mentioning an organization that works towards that end, for people that are not HAMs or want more info.
Check out the Amateur Radio Relay League's website: http://www.arrl.org/
- Rob - KE6FTH -
Re:So what happens to Technicians?
Excerpted from http://www.arrl.org/news/stories/2006/12/15/104/:
... the FCC's action in WT Docket 05-235 appears to put all Technician licensees on an equal footing: Once the R&O goes into effect, holders of Technician class licenses will have equivalent HF privileges, whether or not they've passed the 5 WPM Element 1 Morse examination.
So, it sounds like they're promoting Technicians instead of demoting Tech. Pluses. -
Shouldn't FCC drop ham radio completely ?
After all, ham radio is no more what it used to be: try listening to the frequencies used by radio amateurs, and ask to yourself if these frequencies shouldn't be used for something more useful (emergency services managed by real professionals, wireless networking, broadcasting, etc.). There is no more real experimentation being done today by radio amateurs, and internet offers a better way to communicate, without the trouble of getting a licence, buying a station, raising an antenna, and so on.
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Re:I might become one.
I, too, just received my Tech. license. I did get one of the formentioned books from the ARRL which focused on the FCC licencing requirements needed. Somewhat disappointed in the text (it wasn't as in-depth as I would have liked, especially from a "how to operate" standpoint), but that can be made up from other sources like the aformentioned books and listening to people actuallying operating (ok... maybe not so much...)
I also found some good online websites (I've lost the references...) that will quiz you using the question pools available to see if you know your stuff. Resist the temptation to memorize the question pool unless you understand the "why" behind the questions asked.
Having said that, if you have a technical background (doesn't NEED to be electrical... this ChE passed easily), and can use some common sense (which helps remebering many of the simple FCC regulations), the test is a simple multiple choice exam. With the online study, and what you learn studying for Technician, you may even be able to pass the General exam as well (I came short by 3 questions...and I didn't even study for it!).
As for the Morse requirement, I am having a hard time with it. I can hear the differences, but the brain is not doing so well in tying the rhythm with a letter. So, I'm happy that I can progress without knowing it, but at some point I will force myself to pick it up. (Been trying to decode a beacon on 6M around here... I know what it should be saying, but I haven't been able to pick up anything past VVV)
Good luck!
KC2QLC -
Re:I might become one.
The ARRL Handbook, as good as it is, gets dense rather quickly. ARRL publishes a number of good introductory books. A couple that might be of use are Basic Radio and Understanding Basic Electronics.
Another good book, long out of print but maybe available used in various places, is Understanding Amateur Radio. I picked up a copy of it back in the early '80s and it helped my self study of electronics immensely. -
Re:I might become one.
The ARRL Handbook, as good as it is, gets dense rather quickly. ARRL publishes a number of good introductory books. A couple that might be of use are Basic Radio and Understanding Basic Electronics.
Another good book, long out of print but maybe available used in various places, is Understanding Amateur Radio. I picked up a copy of it back in the early '80s and it helped my self study of electronics immensely. -
Re:I might become one.
The ARRL has plenty of books on how to study for the FCC exams. I recently just received my technicians license, which is the most basic license. There are books there that will teach you all of the requirements that you need to learn to pass the FCC exam. However, if you want to learn about electronics, then any Ham will tell you to pick up a copy of the ARRL Handbook.
I own the Handbook and am an electrical engineer by trade. The Handbook is certainly a book that will give you examples of how to build radios yourself without bogging the explanations down with a lot of math. If you like explanations with more mathematical rigor, then you will have to go elsewhere. However, the book does an effective job of explaining circuits with some very creative examples.
The ARRL web site also has a directory of local clubs and events. Usually there is a point of contact associated with the club and they can give you a hand.