Slashdot Mirror

The null spot is due to ground wave vs. sky wave differences and skywave propagation characteristics. Sky waves are completely propagated by refraction off of the ionosphere. Ground waves propagate along the ground in a fashion similar to propagation along a transmission line such as a wire or waveguide. The sky wave is received back on earth only because of Snell's Law of Refraction - remember "critical angles" from physics. Think of reflection in water that only happen at certain angles.

There are two factors in the case of the Boulder Null.

The first due to the fact that WWV transmitters and antennas are in Ft Collins while you are in Boulder with mountains in between. If you had a clear path to Ft. Collins (e.g. in nearby Denver) you could get a ground wave.

The second is due to antenna design. WWV is intended for world-wide time service so the antenna is designed to maximize sky wave and also minimize ground wave. The sky wave is optimized to have the lowest "wave angle" to maximize the propagation distance (to the other side of the earth, ideally).

However this also minimizes the local reception. You can't get a sky wave in Boulder because you are still too close to the transmitter to catch the first bounce off the ionosphere. At WWV's frequencies and likely antenna design, you'll usually catch the first sky wave reflection at distances not less than 250-500 miles from the antenna.

These combined help to create the null in Boulder.

The cover of this ARRL book "Your Guide to Propagation" has a diagram of exactly what's happening above: the antenna in the middle is Boulder; the antenna on the left is Ft. Collins WWV. The little arrow just to the right of Ft. Collins is the ground wave path. The arrows heading up into the sky are the sky wave paths. Then imagine a mountain between the left and middle antennas.

[Cover Image]

Some other clarifications for other comments:

1. The broadcast transmitters for WWV are in Ft. Collins, not Boulder. Front-end overload isn't a problem or cause.

2. Modulation doesn't affect propagation, per se - it doesn't matter if you use AM, FM or 64 QAM. Well, you could argue that sideband distortion is a propagation issue, but that's more of a 2nd order effect. You can subsume that as S/N ratio or Bit-Error-Rate (BER)spec. Only S/N ratio or BER is affected by modulation choice.

3. Atmospheric water doesn't have any effect on radio propagation until you get into VHF (30 MHz < f < 300MHz) and becomes a major component only at UHF and above (f > 300 MHz).

So FM radio (88-108 MHz) can be affected by the weather, but WWV (2.5, 5, 10, 15, 20 MHz) and broadcast AM (0.68 - 1.7 MHz) are not. The latter are affected by solar or geomagnetic weather i.e. sun spots and solar flares.

If you want to learn more pick up copies of the ARRL Antenna Book and the ARRL Propagation Handbook.

ARRL Books on Antennas & Propagation

JG

The null spot is due to ground wave vs. sky wave differences and skywave propagation characteristics. Sky waves are completely propagated by refraction off of the ionosphere. Ground waves propagate along the ground in a fashion similar to propagation along a transmission line such as a wire or waveguide. The sky wave is received back on earth only because of Snell's Law of Refraction - remember "critical angles" from physics. Think of reflection in water that only happen at certain angles.

There are two factors in the case of the Boulder Null.

The first due to the fact that WWV transmitters and antennas are in Ft Collins while you are in Boulder with mountains in between. If you had a clear path to Ft. Collins (e.g. in nearby Denver) you could get a ground wave.

The second is due to antenna design. WWV is intended for world-wide time service so the antenna is designed to maximize sky wave and also minimize ground wave. The sky wave is optimized to have the lowest "wave angle" to maximize the propagation distance (to the other side of the earth, ideally).

However this also minimizes the local reception. You can't get a sky wave in Boulder because you are still too close to the transmitter to catch the first bounce off the ionosphere. At WWV's frequencies and likely antenna design, you'll usually catch the first sky wave reflection at distances not less than 250-500 miles from the antenna.

These combined help to create the null in Boulder.

The cover of this ARRL book "Your Guide to Propagation" has a diagram of exactly what's happening above: the antenna in the middle is Boulder; the antenna on the left is Ft. Collins WWV. The little arrow just to the right of Ft. Collins is the ground wave path. The arrows heading up into the sky are the sky wave paths. Then imagine a mountain between the left and middle antennas.

[Cover Image]

Some other clarifications for other comments:

1. The broadcast transmitters for WWV are in Ft. Collins, not Boulder. Front-end overload isn't a problem or cause.

2. Modulation doesn't affect propagation, per se - it doesn't matter if you use AM, FM or 64 QAM. Well, you could argue that sideband distortion is a propagation issue, but that's more of a 2nd order effect. You can subsume that as S/N ratio or Bit-Error-Rate (BER)spec. Only S/N ratio or BER is affected by modulation choice.

3. Atmospheric water doesn't have any effect on radio propagation until you get into VHF (30 MHz < f < 300MHz) and becomes a major component only at UHF and above (f > 300 MHz).

So FM radio (88-108 MHz) can be affected by the weather, but WWV (2.5, 5, 10, 15, 20 MHz) and broadcast AM (0.68 - 1.7 MHz) are not. The latter are affected by solar or geomagnetic weather i.e. sun spots and solar flares.

If you want to learn more pick up copies of the ARRL Antenna Book and the ARRL Propagation Handbook.

ARRL Books on Antennas & Propagation

JG

Nitpick: 802.11b is generally Part 18, which is Industrial, Scientific, & Medical, vs Part 15 Radio Frequency devices. Phones, baby monitors, etc, generally fall in to the Part 15 space. The distinction is important; operators of Part 15 devices are responsible not to cause harmful interference with other users. Part 18 devices do not have the same requirements. To quote the ARRL's doc on part 15 & 18:

[...] if the ISM equipment is operating properly in its assigned band, any RFI it is causing must be accepted or corrected by the entity that is receiving the interference, including amateurs.

I don't think amateurs, or their main (US) organization, the ARRL, are against WiFi. I have a WiFi network at home and work, and hold an Extra class amateur license. I often sit at my radio with laptop and WiFi to hunt the net for rare stations on the air and to log. :-) I wouldn't be shocked if someone were to Netstumble around Newington, CT, they'd find a couple access points at ARRL HQ. Heck, I've seen initial discussions on a couple of mailing list whether putting an 802.11b device in space on an amateur satellite is doable from a protocol latency point of view, and from people who have put amateur satellites into space. :-)

In my ideal world, WiFi would get their own chunk 'o bandwidth to use that wouldn't interfere with anyone except themselves. I know the ARRL is pushing for amateurs to have a primary allocation in a portion of the amateur allocation at 2.4Ghz, but I don't think that would affect the standing with ISM devices. Anyone know differently?

Nitpick: 802.11b is generally Part 18, which is Industrial, Scientific, & Medical, vs Part 15 Radio Frequency devices. Phones, baby monitors, etc, generally fall in to the Part 15 space. The distinction is important; operators of Part 15 devices are responsible not to cause harmful interference with other users. Part 18 devices do not have the same requirements. To quote the ARRL's doc on part 15 & 18:

[...] if the ISM equipment is operating properly in its assigned band, any RFI it is causing must be accepted or corrected by the entity that is receiving the interference, including amateurs.

I don't think amateurs, or their main (US) organization, the ARRL, are against WiFi. I have a WiFi network at home and work, and hold an Extra class amateur license. I often sit at my radio with laptop and WiFi to hunt the net for rare stations on the air and to log. :-) I wouldn't be shocked if someone were to Netstumble around Newington, CT, they'd find a couple access points at ARRL HQ. Heck, I've seen initial discussions on a couple of mailing list whether putting an 802.11b device in space on an amateur satellite is doable from a protocol latency point of view, and from people who have put amateur satellites into space. :-)

In my ideal world, WiFi would get their own chunk 'o bandwidth to use that wouldn't interfere with anyone except themselves. I know the ARRL is pushing for amateurs to have a primary allocation in a portion of the amateur allocation at 2.4Ghz, but I don't think that would affect the standing with ISM devices. Anyone know differently?

There are a series of amateur radio satellites in orbit sponsored by members of The Radio Amateur Satellite Corporation and other organizations worldwide. They are free to use worldwide by anyone holding an amateur radio license. Most of these satellites are in low earth orbit, which means that they may make several passes a day. It does not take much to get started. You can communicate with other radio amateurs through these satellites with nothing more than a handheld antenna pointed at the sky and a handheld radio clipped to your belt. I use this antenna.

Yes, I know that I can whip out my cellphone and talk to anyone with much less effort. But I am a geek and this is much cooler (and fun!)

If you are in the U.S. check out the American Radio Relay League's web site for more information on getting licensed. If you are outside the U.S., check the above web site for information on getting licensed in your country. It's easy!

Digital modes (i.e. PSK-31) are becomming more popular. Who said you couldn't try to play Quake against the group on the next mountain over.

With more and more levels of technologies when using computers these days, it's neat to see radios work from coast-to-coast with little more than a wire strung between trees. Geek campouts at its most basic.

This is an Amateur Radio satellite, so you need an Amateur Radio license to work it.

See www.arrl.org/hamradio.html

for a general overview of Ham radio.

Then you can set up your radios and antennas.

A page was referenced, but posted by an AC so its only at 0. Here's the link again: www.qsl.net/vk3jed/1st_sat.html

As for books, look around the ARRL site, they have a vast collection of good books.

-----------
73 de K6LNX

Another good article can be found here, at the home of the American Radio Relay League, the north american Secretariat of the International Amateur Radio Union.

The ARRL has a quick guide to getting started. Buy Now You're Talking! All You Need For Your First Amateur Radio License ($19) from the ARRL or your local Radio Shack. Your local clubs may offer classes too. Read the book, get tested ($10), answer 35 multiple-choice questions that you've already seen in the book, and you will have a Technician Class license. Buy a hand-held radio (about $130) that you can use with repeaters for and you are in business.

The ARRL has a quick guide to getting started. Buy Now You're Talking! All You Need For Your First Amateur Radio License ($19) from the ARRL or your local Radio Shack. Your local clubs may offer classes too. Read the book, get tested ($10), answer 35 multiple-choice questions that you've already seen in the book, and you will have a Technician Class license. Buy a hand-held radio (about $130) that you can use with repeaters for and you are in business.

The newer event which you refer to, AMSAT FD, is world-wide, and lasts longer, satellite contacts only.

ARRL FD is mostly Region II (the americas). In prior years, only US and Canadian stations competed, but this year all Region II (NAM/CAM/SAM) stations may compete. Contacts with I & III count for the Region II station, if the DX gives (or can be prompted to give) a proper Exchange (1D mostly likely, if they're home on commercial power).

Many HF radio contests are worldwide in nature as you suggest. This one is not restricted to HF, but is MW-HF-VHF+, and is specifically termed an Operating Event. It is a mixture of a Contest and a wide-area Drill. It differs from a Simulated Emergency Test in not having a disaster scenario, and in having contest-rules and scoring; everyone is out in the field as if they were the affected area. We're demonstrating that we can restore communications locally and wide area from improvised positions. Other countries' national associations have their own Field Days on other weekends.

A FD station may participate in both. The first AMSAT contact with full ARRL exchange is 100 bonus points on the ARRL, and each additional is another QSO point, and doesn't count against band/transmitter limits.

73 de Bill N1VUX
I'll be operating at W1BOS VHF+ positions, and visiting other Metro-Boston sites for ARES

Site dedicated to ham radio contesting

ARRL DX Contest (soapbox comments

November Sweepstakes Comments

Contest Calendar

General Ham Radio Info

this is KF8QE

Site dedicated to ham radio contesting

ARRL DX Contest (soapbox comments

November Sweepstakes Comments

Contest Calendar

General Ham Radio Info

this is KF8QE

Site dedicated to ham radio contesting

ARRL DX Contest (soapbox comments

November Sweepstakes Comments

Contest Calendar

General Ham Radio Info

this is KF8QE

Here's a reasonable explanation from the ARRL

From the National Association for Amateur Radio:

Why Ham?

"Ham: a poor operator. A 'plug.'"

That's the definition of the word given in G. M. Dodge's The Telegraph Instructor even before radio. The definition has never changed in wire telegraphy. The first wireless operators were landline telegraphers who left their offices to go to sea or to man the coastal stations. They brought with them their language and much of the tradition of their older profession.

In those early days, spark was king and every station occupied the same wavelength--or, more accurately perhaps, every station occupied the whole spectrum with its broad spark signal. Government stations, ships, coastal stations and the increasingly numerous amateur operators all competed for time and signal supremacy in each other's receivers. Many of the amateur stations were very powerful. Two amateurs, working across town, could effectively jam all the other operators in the area. When this happened, frustrated commercial operators would call the ship whose weaker signals had been blotted out by the amateurs and say "SRI OM THOSE #&$!@ HAMS ARE JAMMING YOU."

Amateurs, possibly unfamiliar with the real meaning of the term, picked it up and applied it to themselves in true "Yankee Doodle" fashion and wore it with pride. As the years advanced, the original meaning has completely disappeared.

From the National Association for Amateur Radio:

Why Ham?

"Ham: a poor operator. A 'plug.'"

That's the definition of the word given in G. M. Dodge's The Telegraph Instructor even before radio. The definition has never changed in wire telegraphy. The first wireless operators were landline telegraphers who left their offices to go to sea or to man the coastal stations. They brought with them their language and much of the tradition of their older profession.

In those early days, spark was king and every station occupied the same wavelength--or, more accurately perhaps, every station occupied the whole spectrum with its broad spark signal. Government stations, ships, coastal stations and the increasingly numerous amateur operators all competed for time and signal supremacy in each other's receivers. Many of the amateur stations were very powerful. Two amateurs, working across town, could effectively jam all the other operators in the area. When this happened, frustrated commercial operators would call the ship whose weaker signals had been blotted out by the amateurs and say "SRI OM THOSE #&$!@ HAMS ARE JAMMING YOU."

Amateurs, possibly unfamiliar with the real meaning of the term, picked it up and applied it to themselves in true "Yankee Doodle" fashion and wore it with pride. As the years advanced, the original meaning has completely disappeared.

http://www.arrl.org/hamradio.html

From that article ...

"Amateur Radio is central to the whole flight," said Eric Knight, KB1EHE, of Unionville, Connecticut--one of the hams involved. He explained that the rocket's Automatic Position Reporting System (APRS), amateur TV and packet telemetry gear will enable the team to document its success.

Another ham band, 13 cm (2.30-2.31 GHz and 2.39-2.45 GHz), overlaps the Part 15 spectrum at 2.435-2.465 GHz.

Theoretically, hams (and everyone else) have priority over Part 15 devices, but just try explaining that to an angry neighbor.

The complete amateur radio regulations for the USA can be found here. The USA is in ITU region 2, except for some Pacific islands in region 3.

Please keep in mind that the poster is an Amateur Radio Operator and is not restricted by the regulations you posted. I don't mean to imply that hams are not bound by FCC regulation, just that it so happens that Amateur Radio is the Primary Service in the frequency allocation you refer to. The regulations you post apply to the Secondary Service in this frequency range.

Wrong. I operate regularly on 1.2 and 2.4 GHz. I have a friend that runs at 10GHz. Hams are primary on 2.4. Here is a handy link that shows the ham bands.

Ham Spectrum Allocation

From the FCC database:

TUTTLE, THOMAS J, KB1EVZ
88 WESTOVER ST
WEST ROXBURY, MA 02132

Lesson: If you are a licensed radio amateur in the U.S. you must keep your name, call sign, and address secret. If one is revealed, the rest might be too.

The real irony is the insanity of hams, who at qrz.com have been expressing their outrage at the very anonymity usually allowed on the web. Most of them think anyone who posts messages on web forums should reveal much of their personally identifying information, including full name, phone number, and street(!) address (for what reason? stalking, perhaps? maybe assault, or even murder?). This is why ham radio is dying.

Wouldn't these cameras be illegally interfering with amateur radio bands?

Here's a link: Earth-Moon-Earth

Further, section 97.115 places severe restrictions on messages that may be sent by an amateur station when they did not originate at that station.

That's what I mean by limited.

Of course, you sig, "Disinfect the GNU General Public Virus!", kinda tells us what you are all about.

Oh, really? What does it say to you? Probably not what you think it says. Hint: I'm not a M$ toady.

Further, section 97.115 places severe restrictions on messages that may be sent by an amateur station when they did not originate at that station.

That's what I mean by limited.

Of course, you sig, "Disinfect the GNU General Public Virus!", kinda tells us what you are all about.

Oh, really? What does it say to you? Probably not what you think it says. Hint: I'm not a M$ toady.

First off you must be ham radio operator. Since these all operate above 50Mhz, this means you can get by with a Tech license which is no code, just study and pass the written test. Sites to check for ham radio licensing info include E-Ham and the ARRL.

Second, any system with more that 1 watt output must be under automatic control so that only enough power as required to compleate the communication is used. You just can't pump out 100 watts to go next door. Not that 100 watts at 2.4Ghz is easy to come by...

The nice thing is that is looks like you don't even have to touch some of the boards to do this. Talk to the manufacture, show them your license and they'll set you up with boards in the ham bands right off the bat! Nice!

BWP

They got permission.

http://www.arrl.org/news/stories/2000/10/18/1/#gar min

In fact, at some point, UWB will inevitably lead to interference. That is a simple fact of how radio works. The only question really is how much power and what UWB applications one can permit before UWB-related interference for non-UWB services becomes a real problem.

In fact, at some point, UWB will inevitably lead to interference. That is a simple fact of how radio works. The only question really is how much power and what UWB applications one can permit before UWB-related interference for non-UWB services becomes a real problem.

The correct fix would be a little 6-10db amp on the output of the Linksys, giving nice, clean power out to that 18db dish. Anyone have a source?

My suggestion would be Down East Microwave . They have lots of quality hardware. They say they won't sell 2.4 gHz stuff to non-hams but if you know enough to use the hardware, you can probably bluff your way along.

A 21dB pre-amp (for the RX end) is just $85 (and totally legal for anyone to use). If you are not a ham and want to break federal laws, check out their 2.3-2.4 linear amp. With one watt drive, it'll put out 15 watts. They make an amp that will put out 120 watts but it requires 10-20 watts of drive.

Trust me, folks, if you know a bit about electronics and want to do cool radio stuff, get a ham license. It'll cost you less than $20 (plus the cost of a book if you want to study first). In coolness alone, you'll be paid back many times over.

InitZero

don't forget the fact that during the sept 11th disaster that amatuer radio was found nearly essential when all major forms of communication - including cell phones, police and fire radio systems broke down.

interesting tidbit

For those moderators not paying attention, the parent post is an obvious troll.

This is precisely why we need the FCC to regulate people's use of this equipment.

Cringely's setup is regulated by the FCC and is within FCC specifications. There is nothing illegal (as far as the FCC is concerned) here.

Did Bob Cringely ask a single person living in downtown what they thought of his terrific internet access plan?

Why would he? Does the neighborhood get a vote every time someone turns on a cell phone? What about when a ham radio operator fires up his 1,500 watt amp? What about when someone turns on a microwave oven?

What about the those people who use approved wireless equipment (phones, wireless networking) and now have to deal with the background noise

Cringely was using an FCC type-accepted device well within its specifications. Did you miss that part of his article?

coming from his souped up repeater?

His 'souped up repeater', as you call it, is a couple of antennas back to back. It's passive. His antennas don't put out power, they just focus the energy. With 18db of gain, his 100mw signal is still under five effective watts.

Wait, I'm sure he did a thorough study of his setup to make sure that it didn't interfere with transmissions by public safety agencies, right?

Dude, take a basic radio class. He isn't changing the operational frequency. He isn't using an illegal amp that might cause out of band splatter. His third order distortion won't be affected by a passive antenna. There is harmless.

What stopped him from using a 10 watt transmitter, so that the connection would be even faster?

If he had a ham radio license, he could legally run up to 1,500 watts of power, operate an active repeater and use whatever antenna array he wanted all in the same frequency range he is using now. As an added bonus, he still wouldn't have to fill out any paperwork, get any government approval or take a poll of his neighbors.

Follow the rules and don't subject other people to your homebrewed technology.

Once again, other than unlawful use of a tree for the purposes of geekness, I he hasn't broken any rules.

If you want to learn something about radio (and, trust me, you're really ignorant now), why not surf on over to the American Radio Relay League. They represent hams across the world. They have some very good teaching materials. If you study hard, maybe you can even get a ham license. It really is pretty nifty.

InitZero

ECAD is electronic computer aided design. There are low cost packages, some are even freeware. Get a package as soon as you can.

You will get schematics that are automatically legible, plus you will get automatically generated net lists telling you exactly which pins of which chips are supposed to be connected to each other. If you're wiring up a circuit by hand, this is amazingly good information to have, especially if it's accurate.

Here's a freeware package, I think it's good for 16 IC equivalents. Check McCAD . Perfectly adequate for hobbyist or student. Their shrinkwrap unlimited version is thousands of dollars and has more power than you have any idea how to use at this point.

Get a good basic set of hand tools, there are plenty of hobbyist kits.

In addition, include a decent wire-wrap gun if you plan to work in digital. Your technique of choice if you aren't buying a kit with a PCB is going to be wirewrap on perforated boards into which you've plugged lots of 8-64 pin wirewrap sockets into. Get the socket ID labels. These items, except for the (I said decent) wrap gun, you can get at Radio Shack. You might check ebay for a deal on a pro wire-wrap gun.

You need a DMM (Digital mulitmeter), an analog VOM (volt-ohmmmetter, this will generally have a current measurement range large enough to be of us, look for several amps measurement capability, and an oscilloscope, at least 100 MHz, look for a used Tektronix.

Look hard for a decent electronics surplus store in your area, you might get some spectacular deals on test gear and the more expensive tools.

Find out where the electronics "pro shop" in your area is, for the stuff that Radio Shack never did and never will sell. You'll pay a premium, but it beats waiting for shipping if you need it NOW.

The ARRL Handbook from the ARRL ham radio organization is a good starting point, as their other tutorial guides are.

For where/how to get electronics info that's actually useful, try the electronics section on my site http://www.ecis.com/~alizard/index1.html#electroni cs

Numbers are fun but tough without a bug.
one = di dah dah dah dah
two = di di dah dah dah
three = di di di dah dah
four = di di di di dah
five = di di di di dit
six = dah di di di dit
seven = dah dah di di dit
eight = dah dah dah di dit
nine = dah dah dah dah dit
zero = dah dah dah dah dah
Can't count these in your head above 13 words/minute. Got to listen for the rythym of the code (Anyone else remember that tape?)

Neither this article, nor the previous one posted on /. mention what the USNA plans to do with the satellite.

Ham radio operators all over the world (please view with Netscape; it doesn't load right with IE) use a nifty packet application, APRS through PCSat.

APRS is short for Automatic Position Reporting System. Basically, the satellite allows hams to send GPS reports (such as mine), short text messages, weather reports, etc. to a large number of users. The satellite acts as a 'digital repeater'. Any packet it hears, it send back to earth.

To hit the satellite, all you need is a hand held radio running less than five watts of power into the stock 'rubber duck' antenna. If you're a boater, hiker or whatnot that isn't in range of land communications, you can easily send your data through the satellite and have it relayed to a huge earthly footprint.

Over much of the populated world, there are land based digital repeaters that will relay these packets for hams. Many even gate the information to the internet where it can be viewed by anyone.

If you're the least bit technically and electronically minded, you can probably get the base level ham license (Technician) without any difficulty. It doesn't require a knowledge of Morse Code (CW) anymore. You can take the sample Tech test online. The sample test uses real questions right off the FCC exam. The test costs under $10 in most areas.

Using more than a dozen ham radio satellites for free isn't the only reason to get your ham license, of course. There's also that you can modify those 2.4 gHz network cards to run up to 1,500 watts of power legally instead of under half a watt as sold. Think what kind of distance you could extend your network! (And how many birds flying nearby will be microwaved!)

If nothing else, a ham radio license will get you another punch in your 'biggest geek' card. Who doesn't want that?

Matt (k4mls)

Don't tell Mr. Firstenberg, but Mendocino lists a good dozen hams, and I'd have to believe that Mendocino county hasn't been terribly effective in telling the FCC they're the boss.

According to the ARRL's callsign lookup for zipcode 95460, there are 14 hams listed in the community. The town also sports a amateur radio club - Willits Amateur Radio Society (look at their stated objectives for reference to their county).

And I'd have to bet the local luddites haven't been too effective in shutting off satellite reception, AM, FM and broadcast TV reception, licensed microwave, 800 MHz trunking (e.g. city/county police, fire and roads), etc.

So I'm terribly curious how this RF allergy is only affected by specific frequency bands - e.g. 900 MHz analog cellular (but not amateur use of 900), PCS around 1.8 GHz, 2.4 GHz ISM and 5.3/5.8 U-NII allocations?

Even more curious is that I don't see any reference to the pulsed microwaves emitted by microwave ovens - approximately 2.4 GHz devices that often carry 500 watt radios and leak significantly more RF than the receive end of a 2.4 GHz wireless ISP transmission (e.g. -55 to -85 dBm).

Apparently the energy crisis wasn't enough for these mysticism-led luddites. They probably won't be happy until the state is living in an ag commune...

*scoove*

I'd even bet that if we moved service into another frequency assignment, the allergy would follow.

Also, just as a totally useless aside, looking at my handy-dandy (three or so years old) frequency chart I have here, I find it interesting that that portion of spectrum used to be for amateur radio operators. Co-located, perhaps, or did they just take it away from the amateurs altogether?

It is still an amateur allocation. I believe part 15 devices (such as wap and cordless phones) are a tertiary allocation.

That band is used by amateurs. As a matter of fact, there was a recent incident involving an apartment building wired for 802.11 that was interfering with some amatuer use of the band. Another reasonb why you don't want to increase your output power without reason. All of this stuff can work together just fine as long as people realize that if 10mW does the job, you don't need to be running 1W of output power.

Excerpt from the ARRL Letter, Volume 20 Number 7

FCC QUERIES WIRELESS 'NET PROVIDER ABOUT INTERFERENCE TO HAMS

The FCC has asked a wireless Internet system provider what it intends to do
to eliminate interference to Amateur Radio operations in the Dallas, Texas
area. The FCC wrote Darwin Networks Inc on February 8, 2001, regarding
complaints of harmful interference to Amateur TV on 2.4 GHz that's said to
be a result of the company's deployment of Part 15 devices in an apartment
complex.

The SARA, ARRL or DX zone. You've probably done the google search for "amateur radio telescope"
Given that you have the hardware it would seem you need to find someone who has the skills to design the thing. My guess is that your local ham or astrology club would have people who have the knowledge and desire to help. Do you have a university close by, prehaps they might want to take it on as a grad project. But my first port of call would be SARA.
IMHO this is the sort of question that /. should post, I doubt there will be many posts but who cares. I want thought provoking or interesting questions. In short I want questions that make me go and hunt down some ideas.

Tune in the Universe -- Amateur Radio and the Search for Extraterrestrial Intelligence

I totally disagree with your comments. Amateur radio still provides a usefull service in more ways than one.

First of all, the amateur radio operators compose a network of communications that the most completely decentralized form of communication available. While cell phones, satalites, and internet connections are all very hi-tech, they all have central points for failure. It is virtually impossible to knock out amateur communications without killing almost every operator! One or two switching stations or a satallite and cell phones are dead.

Secondly, many of the 'ham-nerds' you speak of are some of the most brilliant electircal engineering type people I have ever met. Many technologies that we use today can be attributed to amateur radio, including the roots for wireless connectivity such as 802.11 (ever heard of packet radio?). You can also find the roots of cell phones in amateur radio.

Thirdly, amateur radio operators provide many valuable services to the community including community service, education, and Disaster Relief (WTC).

I totally disagree with your comments. Amateur radio still provides a usefull service in more ways than one.

First of all, the amateur radio operators compose a network of communications that the most completely decentralized form of communication available. While cell phones, satalites, and internet connections are all very hi-tech, they all have central points for failure. It is virtually impossible to knock out amateur communications without killing almost every operator! One or two switching stations or a satallite and cell phones are dead.

Secondly, many of the 'ham-nerds' you speak of are some of the most brilliant electircal engineering type people I have ever met. Many technologies that we use today can be attributed to amateur radio, including the roots for wireless connectivity such as 802.11 (ever heard of packet radio?). You can also find the roots of cell phones in amateur radio.

Thirdly, amateur radio operators provide many valuable services to the community including community service, education, and Disaster Relief (WTC).

I totally disagree with your comments. Amateur radio still provides a usefull service in more ways than one.

First of all, the amateur radio operators compose a network of communications that the most completely decentralized form of communication available. While cell phones, satalites, and internet connections are all very hi-tech, they all have central points for failure. It is virtually impossible to knock out amateur communications without killing almost every operator! One or two switching stations or a satallite and cell phones are dead.

Secondly, many of the 'ham-nerds' you speak of are some of the most brilliant electircal engineering type people I have ever met. Many technologies that we use today can be attributed to amateur radio, including the roots for wireless connectivity such as 802.11 (ever heard of packet radio?). You can also find the roots of cell phones in amateur radio.

Thirdly, amateur radio operators provide many valuable services to the community including community service, education, and Disaster Relief (WTC).

Amateur radio operators still have access to huge amounts of valuable spectrum. While HF (shortwave) bandwidth is somewhat limited, it is successfully shared with a multitude of other services: military, industrial, broadcasters. Hams also have access to TONS of VHF and UHF bandwidth, especially in the GHz and up range, that are prime experimenting ground for whatever your heart desires. The price of entrance is passing a straightforward license exam. My point is that the RF spectrum is not entirely "owned". If you want to play, you don't necessarily have to pay. More information about becoming a ham here.

FYI, "frequency" has little to do with "range". Pick up an ARRL handbook at your local library.

The biggest obstacle to amateur radio being used for this purpose is licensing. Everyone who operates a transmitter on this theoretical network would need to be licensed. It might be possible for your kids or wife to use the system if you are present (third party traffic), but that's no good when you're not around.

I'll reiterate that no encrypted connections would be tolerated, but if you send your music in MIDI form, some people would consider that acceptable. As far as "commercial stuff goes," recent rulings have suggested that everything except the actual sale may be conducted online; some clubs run "Swap n' Shops," etc.

Yes, I am a licensed amateur radio operator. No, do not take this as gospel; I have study books from various years that contradict each other. Amateur radio frequencies likely won't be up for grabs anytime soon; they are used for emergency management and are partially regulated by the International Telecomuncations Union.

For more information on Internet and ham radio, visit ampr.org. Everything 44.*.*.* online has been an amateur radio station since the 1970's. Note that most of these (to be legal) do not allow you access to their systems. That could qualify as unauthorized operation of a radio tranmitter on their part.

And if you want to know how over 350 amateur radio operators worked over 5000 man-hours helping in the aftermath of September 11th, go here.

By law, these devices can only emit 100 mW at peak. In addition, they must not cause harmful interference.

Right now, with 11a, you may have less to worry about; however, there are a LOT of users of 11b's radiospace. Cordless phones primarily, but you have to also worry about the neighboring services, like wireless broadband and DBS/DSS reception (which grabs a fairly sensitive signal).

Not to mention radio amateurs, who have a bit more priority over the spectrum than you do. (If you're a ham, and can figure out a way for the stations to emit callsigns in a clear, common, and unencrypted way, then game-on.)

Link: Part 15 Rules

I'm not sure of the exact speeds yet, but we are going to be experimenting with using laser for linking APs in Brismesh. Here's some links:


http://www.qsl.net/wb9ajz/laser/laser.htm

http://www.arrl.org/tis/info/laser.html

http://www.gbonline.com/~multiplx/wireless/laser /

http://www.emn.org.uk/laser.htm

http://www.n1bug.net/tech/laser/alc_wa6ejo.html

That last link explains how to get around the modulation problems that can slow down standard laser diodes. You find some of these links useful.

David

If all goes well, you should be able to at least hear the downlink packets with a VHF scanner and 1/4 wave vertical antenna (YMMV). You will need a AX.25 TNC and terminal or comparable sound-card software to see the telemetry from the satellite and APRS position reports that get relayed through the satellite. Note that locations in the US will have to wait about 9 orbits before they can hear anything.

More info on the PCSAT web page. You can learn more about amateur radio at the ARRL web page and about amateur satellites at the AMSAT web page.

73, KA1LM