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Speaking of RC and amateur devices, I'm surprised that they didn't just use APRS to keep track of the balloons. The power budget of a GPS and VHF transmitter are tiny and they can tie into the network (almost) no matter where, or how high, the balloon goes.

The transmissions aren't commercial in nature, so as long as there is a licensed ham there is should be all legal.

Quite often GPS also measures velocity directly. They typically do it by means of tracking the Doppler shifts, which they anyway need to do due to the high velocity of the satellite and position changes in the sky. By doing this, you get very accurate velocities, much better than what you'd get from differentiating position. It's very cool stuff, check it out.

Some description here:

http://www.aprs.net/vm/gps_cs.htm

A GPS typically calculates velocity from Doppler shift of the D-band signal. This give higher accuracy since the position reading is somewhat unreliable. It also means you can (in principle) get the velocity information virtually instantaneously without having to sample two locations. However, in reality a lot of averaging and filtering is going on, and I think many receivers weighs in both position deltas and Doppler shift in the equations, so the reading is going to have at least some lag.

(Reference)

APRS http://aprs.org/ http://www.aprs.net/ http://findu.com/ Just need to use it on an airplane frequency instead of ham, and get everyone else to do the same. Then again, isn't that what ACARS was supposed to be?

The advantage of using dumb old radios is that you can operate independent of any fixed infrastructure, so it's usable even where you don't have cell coverage.

Tracking something small like a dog (I've had inquiries about kangaroos, too) introduces the problem of antenna placement, though. APRS is typically used on the 2-meter band, which means a quarter-wave vertical antenna is half a meter long. I did once put a passive data logger on my cat, and found that she roams a little more widely than I thought, but that doesn't really count.

The advantage of relatively low frequencies and high transmit power is that you can cover a radius of 20 miles from one mountaintop digipeater (equivalent to a cell site), and they're not difficult to make solar powered.

There's a nationwide digipeater network in the US, and most of Europe is covered as well, along with much of New Zealand, Australia, and many other countries. I think there are at least two APRS-capable satellites on orbit too, though PCSAT-1 is dying. Internet gateways are all over the place, so you can map APRS stations online, and not have to maintain any receive-side hardware of your own.

I'm constantly surprised by the applications people come up with for this stuff. The most recent I heard was someone with a cable TV company who found that he could drive around and transmit at low power every couple of seconds and use a receiver back at the headend to plot ingress leaks in the cable system.

Add to that the fact that you can do two-way text messaging, weather, and telemetry, and it's more than worth the hassle of taking a simple multiple-choice license exam. It's this sort of thing that's going to save ham radio (if anything can) - talking to people around the world just doesn't interest people as much these days, when it's so easy to do on the Internet or the phone.

Ham radio operators have been doing this for quite a while. It's called Automatic Position Reporting System.

It was developed by a ham radio operator and the Naval Academy:

http://www.aprs.net/

http://en.wikipedia.org/wiki/APRS

- None of this would even be a question if the inventor hadn't patented it ... the invention simply wouldn't exist!

That's a fun hypothetical situation...but there were digital radio networks a long time ago.

I keep running into that...okay, I can see this compelling situation in which some guy spends years of work to come up with something decades ahead of its time, significantly advancing the state of the art. He doesn't have the resources to develop it, so he wants to go to a big company...but without patent protection, that big company will just swipe his idea.

The *problem* is that in the real world, every time someone seems to claim that they fit into this picture, their idea is nothing special -- they just (rationally) want to take a spin on the Wheel of Fortune (since the patent system allows them to do so) and see if they can get ahold of lots of money.

There are very, very few ideas that are revolutionary. Most are evolutionary. No big jumps, just building a little bit on the stuff beforehand -- ordinary engineering work. The people doing *that* kind of work, the stuff that matters a lot more to society, are being hurt by the people who are exploiting a system designed around funding the production of revolutionary ideas.

The patents were good until RIM bought enough congressmen and lobbyists.

Frankly, I don't think that anyone should even need to drag out prior art. This sort of nonsense should not be patentable, and the fact that can even be considered as such wastes the time of engineers who could be doing more productive things and siphons resources off production of actual good stuff into having a bunch of people sit around in suits and make ridiculous legal arguments.

However, that being said, I would dearly love to hear how you think that RIM "bought the invalidity of the patents". I haven't read all the patents -- just part of the first one -- but even by the USPTO's overgenerous rules, that patent is probably not valid -- people built wireless networks that sent email before that.

By anyone with familiarity with the subject's judgement, this probably shouldn't be patentable (even if the USPTO had decided that they were). For example, look at this. Digital radio networks among hobbyists in *'76*! Before the Apple II! These ideas are not new!

*My* take is that no software patent should ever be granted. The costs of the system far outweigh the benefits.

This has been done for years via APRS. http://www.aprs.net/ http://web.usna.navy.mil/~bruninga/aprs.html It would be much nicer if there was a Google Maps interface for this.

Come up with a new thing to wardrive for. Use a short range antenna to look for outgoing GPS datastreams. Instead of Geocaching, play hunt the transmitting GPS.

It could get interesting though -- if you knew that a specifc car was so bugged, you could go up to it, search it, find the bug, take it apart and find the frequency (or just use a frequency counter), and then start listening on that and similar frequencies. Assuming that the signal isn't strongly encrypted, you could then find every car so tracked in the entire city. In real time.

and from your journal: Next up, sending GPS data over a GPRS cellular modem to an SQL database via the internet and then pulling up the data with a GUI on an internet connected computer.

Why re-invent the wheel, so to speak. Try APRS: www.aprs.net and www.findu.com.

I've got an '03 Murano that I'm winding up to hack. Got the stock GPS and the SAT-ready Bose. Nissan won't sell you a satellite cable for the '03s but there are ways to get them. OTOH, this place is about to release a device that fakes out the radio to accept aux audio in via the unused SAT radio port. The radio controls (next/prev channel, next/prev preset group, presets 1-6) are all passed through their adapter to accessories, and text data is returned to the head unit for display as if it were RDS text. My current idea is to run CAJUN as the jukebox since I'll be able to use the RDS text area to navigate the jukebox menus and browse the music collection. I'd like something no bigger than the new low-profile Linksys routers, with just power, data, audio, a PCMCIA slot, and an internal laptop drive bay. Any suggestions?

Efforts are also underway to document the pinouts of the RGB display so that hopefully an mp3car-like device could share the entire display with all the stock gear. Until then, the 1x20 text line will have to do. Finally, it would also be nice if I could eventually get NMEA GPS **in** since ham radio uses a protocol to place icons on GPS-based maps showing hams' current locations and those of important events. I'd like to have icons automatically appear on my map to indicate the locations of car accidents. That function currently works with Garmin units, but I seriously doubt it will ever work with my Zenrin unit.

Non-hams can try it out with a police scanner tuned to 144.390. If you hear data, you can decode it and display live position data yourself. Linux has had soundcard radio modems for years.

D'oh!

http://www.aprs.net

My bad entirely.

Check out APRS. You will need an amateur radio license, a GPS, a 2m radio and a small interface circuit. If there is a digipeater in your area with an internet link, you will show up on findu.com, and you won't even need a Python script.

"RMS and FSF are seeking power, not freedom."
-Steve Dimse

That from a guy who can't even spell the name of his alma mater. Either that, or he was suckered into getting a degree from a copy-cat diploma mill in malibu.

I have been doing APRS since 1996 or 1997.

But I guess it's nice to know that there is a commercial version avaliable.

You can transmit your position to other units so they can hear you and see where you are.

I have been doing it since 1997. :)

Since I am a ham radio operator, I typically use APRS (Automatic Packet Reporting system), in which many hams have their own weather stations attached to, so you not only get the weather data from the nearest airport, etc. But you get it from many, many locations, and it is plotted on a map which can help alot during a fast moving storm.

The station I use is the Peet Bros. Ultimiter 2000. This company is very helpful, and they even publish the format of the RS232 data!

There are several sites on the net that you can get APRS, such as http://www.aprs.net and if you're not a ham, you can still usually get data from the 'net since many fixed stations gate their data to the net. There are versions for DOS, Linux, JAVA, Windows, MAC, and possibly more. Also, those "trained weather spotters" you hear the news talk about? Most are hams. Go to http://www.skywarn.org to find out more.

73's -.. . -. ---.. ...- .. --

In a related story the FBI has raided the ARRL ham radio HQ looking for antennas and radios that could be used to listen to frequencies, they also confiscated secret PSK31 transmitters that could be used by spies to send signals to spy agencies.

Also discovered was a secret world wide system to track people, cars, boats and planes without the knowledge of the passengers. The secret program, called APRS, violates USC 3, 21 and Janet Reno indicated today that all licensed ham radio operators will be investigated. You may remember that the Branch Davidians used ham radio during the seige at Waco.

I don't see anything new in this. It is basically just a modified APRS setup designed to fit in airplanes, and to be approved by the FAA. Technically, it would be very easy to implement. It could just use standard packet radio operating on aircraft frequencies.

The only realistic way that someone could try to crack the system would be to report an additional plane, or to be actually on a plane and crack the hardware to make it report the wrong position. The system probably wouldn't be used to replace the current system, but to make it more accurate. GPS data at altitude should be very accurate. Most of the inaccuracy of the GPS system is caused by the atmosphere. A mile or two up there is a whole lot less atmosphere to worry about.

Now, what we really need is for the standard ELT's (Emergency Locator Transmitter, one of the black boxes, it is a beacon that goes of when a plane crashes) to include a GPS receiver with a transmitter to report the location of the accident.

Since I am a ham radio operator, I typically use APRS (Automatic Position Reporting system), which many hams have their own weather stations attached to, so you not only get the weather data from the nearest airport, etc. But you get it from many, many locations, and it is plotted on a map which can help alot during a fast moving storm. There are several sites on the net that you can get APRS, such as http://www.aprs.net and if you're not a ham, you can still usually get data from the 'net since many fixed stations gate their data to the net. There are versions for DOS, Linux, JAVA, Windows, MAC, and possibly more. Also, those "trained weather spotters" you hear the news talk about? Most are hams. Go to http://www.skywarn.org to find out more.

This is just another pie in the sky thing that will never fly. The author seems to want something that will 'save' Ham Radio. Well, I'll give him two, both of which have already happened:

Kill the "Old Geezer" Licensing System

Tie Amateur Radio and the New Geekdom together

The first happened April 15th when the FCC (in the United States) decided to eliminate for all practical purposes the testing of Morse code proficiency. (N.B., other countries have done it already.) All you need now to get 99.99995% of the frequencies is knowlege of radio theory and electronics. And, people responded--the FCC was deluged with 20,000 applications for new licenses and upgrades.

The second, which is FAR more important, is the leverage of the Internet savvy, /.-reading, computer-programming, gizmo-hacking crowd into amateur radio. A new mode of Ham Radio operating, the Automatic Packet Reporting System (APRS) ties HF, VHF, UHF, and microwave radio, satellites, the Internet, Palm Pilots, GPS, real-time mapping, and nomadness into one juggernaut of technology. Interested? Check out www.aprs.net and www.tapr.org

/rant QuantumHack, alias KA9MVA, Ham radio guy