Find the ELT and have good breath to boot! Stumbled across this auction, had a nifty article for the description.
http://cgi.ebay.com/ELT-Radio-Direction-Finder-Civil-Air-Patrol-SAR-etc_W0QQitemZ280011704868QQihZ018QQcategoryZ1502QQrdZ1QQcmdZViewItem
Sounds Reasonable, does anyone have experience with one of these?
Assumingly, I've actually heard of the opposite.
I was speaking with a Capt. at my CLC, his past time is well, as many of ours, CAP. However, to narrow it down, he passes time by producing mini-ELTs, broadcasting 121.775. He goes out to Radio Shack, they do indeed have answers, buys a circuit board, with circuits and builds ELTs...
Obviously, they're small enough to hide in a Pringles Can, Coffee Cup, TV's, and of course Simpson's arcade games. The only real problem he stated is it is not a real refined signal (121.775/121.5 in themselves are sloppy, this is worse).
If you're interested, PM, I'll get more details.
So, in jist, on subject, this is entirely possible to perfrom, it's just a matter of knowing how to wire it and being nerdy enough to build it (...now to find the wiring diagram...).
And...the FCC has approved these devices, they have been tested for bleed-over, and are approved for use by CAP and the NTIA?
Try Here to build your own DF: http://webhome.idirect.com/~griffith/tdoa.htm (http://webhome.idirect.com/~griffith/tdoa.htm)
I think were talking transmitters and receivers here guys. The first post is for a "mini-LPER". Does anyone know if they work? Seems easy enough to make. A transmitter is a different story, and it's most likely illegal.
Quote from: Eclipse on August 01, 2006, 09:18:06 PM
And...the FCC has approved these devices, they have been tested for bleed-over, and are approved for use by CAP and the NTIA?
An article was recently written in the California Wing publication about this, in which the designer of these kits goes into more detail on them. Below is an extracted quote answering Capt. William's question, taken from the full article available here: http://cawg.cap.gov/ec/ec06-01.pdf (I believe there are also instructions on making your own, too)
QuoteA fully assembled DF device would require an FCC approval costing thousands of dollars and thwarting my objective to put a cheap, effective receiver into the hands of search-and-rescuers. Selling the device as a kit eliminates that problem, since experimenters can build any kind of receiver they wish, so long as it does not cause interference. And as the RF modules were designed for sale in the U.S. and Great Britain, they already pass FCC muster.
YMMV.
Quote from: Eclipse on August 01, 2006, 09:18:06 PM
And...the FCC has approved these devices, they have been tested for bleed-over, and are approved for use by CAP and the NTIA?
Receivers are not required to be NITA compliant. Maybe unless it's something like a $5000 AOR multiband receiver that is used in some sort of commerical purpose.
I know we all use scanners, air band radios etc...to DF a signal (I personally use a Icom IC-R3 with a digital DF unit programmed in from the factory) and that's fine, but it's always a good idea to keep that L-Per close at hand.
This is pretty cool I think, but personally....I would recommend that we leave things like this alone, at least on a REDCAP. Building something like this would be good for explaining RF/ DF for training purposes ONLY. What if someone's life is hanging in the balance and some kid with his homebrew DF unit causes the whole team to chase a VOR instead of the actual ELT? AFRCC would be very :clap:
Mind you I was not saying go out and buy/build one of these, I just found the article and concept rather amusing. ;D
Quote from: CLB on August 01, 2006, 10:25:19 PM
Quote from: Eclipse on August 01, 2006, 09:18:06 PM
And...the FCC has approved these devices, they have been tested for bleed-over, and are approved for use by CAP and the NTIA?
Receivers are not required to be NITA compliant. Maybe unless it's something like a $5000 AOR multiband receiver that is used in some sort of commerical purpose.
I know we all use scanners, air band radios etc...to DF a signal (I personally use a Icom IC-R3 with a digital DF unit programmed in from the factory) and that's fine, but it's always a good idea to keep that L-Per close at hand.
This is pretty cool I think, but personally....I would recommend that we leave things like this alone, at least on a REDCAP. Building something like this would be good for explaining RF/ DF for training purposes ONLY. What if someone's life is hanging in the balance and some kid with his homebrew DF unit causes the whole team to chase a VOR instead of the actual ELT? AFRCC would be very :clap:
The failure of several commercial radios to meet NTIA specs is due entirely to receiver specs. Having said that, this unit doesn't come under NTIA because it doesn't operate on a military owned freq. 121.5 and 121.775 are FCC assigned freqs.
As for causing interference, they are pretty well shielded inside any metal container.
As for chasing a VOR, I think the narrow band RF module is pretuned to 121.5, which is far enough from the highest VOR freq to not be a problem.
Quote from: SarDragon on August 02, 2006, 07:10:23 AM
Quote from: CLB on August 01, 2006, 10:25:19 PM
Quote from: Eclipse on August 01, 2006, 09:18:06 PM
And...the FCC has approved these devices, they have been tested for bleed-over, and are approved for use by CAP and the NTIA?
Receivers are not required to be NITA compliant. Maybe unless it's something like a $5000 AOR multiband receiver that is used in some sort of commerical purpose.
I know we all use scanners, air band radios etc...to DF a signal (I personally use a Icom IC-R3 with a digital DF unit programmed in from the factory) and that's fine, but it's always a good idea to keep that L-Per close at hand.
This is pretty cool I think, but personally....I would recommend that we leave things like this alone, at least on a REDCAP. Building something like this would be good for explaining RF/ DF for training purposes ONLY. What if someone's life is hanging in the balance and some kid with his homebrew DF unit causes the whole team to chase a VOR instead of the actual ELT? AFRCC would be very :clap:
The failure of several commercial radios to meet NTIA specs is due entirely to receiver specs. Having said that, this unit doesn't come under NTIA because it doesn't operate on a military owned freq. 121.5 and 121.775 are FCC assigned freqs.
As for causing interference, they are pretty well shielded inside any metal container.
As for chasing a VOR, I think the narrow band RF module is pretuned to 121.5, which is far enough from the highest VOR freq to not be a problem.
Even still, I wouldn't use one for anything other than playing around.
I might have been thinking a NDB (Charleston's is 113.5, another close by is 111.0), under the impression some kid makes this thing, messes it up and has his unit chasing morse code TX from the identifier thinking it's the ELT they're supposed to be chasing.
VOR, NDB, AWOS, TAWS, SMOH....it's all Greek pilot talk to me. Ground pounder for life!
Hi, This is Capt. Lord, the designer of the "Altoids ELT Receiver". I sold a bunch of these units to SAR teams, Coast Guard and CG AUX, and of course, CAP people. The only complaint I have had about them is that they dont have the practice frequency on them. ( These are for "real" missions) You need a good directional antenna to get range out of it. I suggest the May 1000, folding Yagi by Diamond antenna. We are seeing if we can steal their design to build a 121.5 dedicated yagi.
As for CAP people building ELT transmitters, I would strongly caution them agains it, especially if they sell them. As I recall, you an get one year in jail and 10,000 fine for every day of illegal operation. Homebuilt units are very likely to bleed over on to 121.5 and set the SAR wolrd into motion. If you can't find a practice ELT, find an aviation handheld radio, and marry it to a foxhunt controller ( Ham radio people will know what I am talking about here) Of course, operate only on our practice frequencies, NOT 121.5.
Check out www.byonics.com for a Fox controller ( You might also look at my APRS transmitter, the Micro-Trak 300 while you are there....)
Capt. A. Lord
(Yes, I am Ian Lord's dad. He is in dirka-dirkastan right now having a good time)
Still won't use one on a REDCAP. Nothing against your engineering skills (which are admirable and certainly creative considering this little thing!)
Christopher,
I certainly understand. My first choice for actual SAR ELT missions is the old L-per. I don't have any personal experience with the new one. The switched antenna DF unit has great bearing resolution, and good sensitivity. A system utilizing a directional Yagi antenna is designed to provide signal acquisition over longer ranges. 4-5 greater range than a switched antenna RDF , but the bearing resolution is nowhere near as good as an L-per. Where a hand-held receiver really shines, is where you are trying to localize the signal to within a few feet. The Deputy Communication Ofcr from Florida Wing described warehouses (metal warehouses!) filled with boats and an Epirb going off inside, Try that with an L-per...Crikey!
I had one mission in Sequoia National Park, in which we had to climb snow covered mountains to acquire signals. having a hand-held would have been great!
My receiver is just a tool. In carrying out our SAR mission, having the tool in the toolbox just improves your flexibilty and responses. I am a big advocate of having the best tools you can find for mission critical applications. I also buy some tools at Harbor Freight, knowing that a tool is sometimes more useful when you know that dropping it down a well won't stop your project! I wish everyone who was ES qualified had access to DF gear, but I know that this is just not feasible. I am making it a little more affordable.
Capt. Lord
to resolve an ELT at an airport, ok, elt in the woods...stay with an L-Per.