PLB alternative?

An acquaintance of mine described an aircraft locating system that sounded promising. As I understand it, a device on the plane periodically transmits GPS coordinates on ham radio frequencies, for which there are many repeaters that can presumably be reached by a flying aircraft. The gps coordinates are automatically entered into a database with a unique identifier. The database can be accessed on the internet, thereby allowing anyone to check the last known location of a plane providing they know the identifier.

Anybody heard of this - do I have the story right? Is there a web site reference? Is this system up and running? Is the database close to real-time?Effectiveness?

erich

(APRS) Automatic Position Reporting Service

It and variations thereof are used by ham radio ops, commercial operations, police/fire/rescue, hikers, etc. For amateur radio, involves transmitting GPS position to ground based repeater linked to internet, etc. Usually used with ground vehicles, personnel, as I'm not not aware of any method to auto switch repeaters as you fly in/out range. Would work fine without switch probably within 75-200 miles of a given repeater, subject to xmtr power and receive performance at each station.

Considerations.

Is the entire country covered by these repeaters?

What will activate a search? If you are flying alone and no one is watching out for you (my case), it could be days or weeks before someone starts asking questions and realizes that you are missing.

Ron Lee said:

Is the entire country covered by these repeaters?

What will activate a search? If you are flying alone and no one is watching out for you (my case), it could be days or weeks befor someone starts asking questions and realizes that you are missing.

Click to expand...

No and no.

Amateur packet radio is an interesting thing. It's a bit like the early days of what we now call the internet, circa 1986 or so. Random links of varying speed and reliability here and there, and no real backbones. For a time, the most reliable links for packet-based email were "store and forward" satellites (OSCAR-14 and -22, dating from 1990). APRS started to come on the scene in the 1990 and was tried with some success by groups like CAP. However, its success has been limited.

The 406 MHz PLB system is a robust, well proven one with lots of government funding and full-time professionals running it. Hits from PLBs are automatically authenticated (checked against the registry) and signals judged to be valid are passed along to AFRCC or others as appropriate. $450 for a PLB seems like a bargain price to access this resource, IMHO.

TODR

Interesting

This would be an interesting idea for aircraft. Of course you would have to obtain your amateur radio license first. There appears to be a national APRS frequency (144.39Mhz) so you would likely have coverage over most of the US. I don't think there is any automatic system that would start a seach if you went down though. There would however be a record of your last known position that could be used by family members or others to initiate a search. A quick Google search revealed TONS of info and websites including maps that show APRS stations that are transmitting at any given time. On one of the maps I even found an aircraft in flight with APRS in west Texas. The stations callsign was KC6SUS.
Here are a couple of links:

http://www.dfwaprs.net/
http://www.aprs.net/

These links show station KC6SUS's info while in flight.

http://www2.findu.com/cgi-bin/find.cgi?call=KC6SUS
http://aprs.he.fi/info/KC6SUS

I'm going to research this more.

Brian,
-KF7TG

PLB

I agree with Doug that amateur radio APRS in it's current state is not really a good alternative to the 406Mhz PLB's. While it can provide position, course, altitude and other info IF someone is receiving your signal, it doesn't let anyone know that you are having an emergency or dispatch search and rescue operations automatically. On the other hand it is sending out this information automatically every minute or so. If I had a choice I'd purchase a PLB first and use the APRS as an experiment.

Brian,
-KF7TG

If you get a 406 MHz PLB....

I strongly suggest getting it with GPS. No guessing about where you are. It should remove the "search" from "search and rescue."

I am pretty self-reliant, and have always felt that my ELT was there because the FAR's required it, and not because it would do much good....but I am amazed at how much more comfortable I am flying over desolate (or even just moderately remote) terrain now that I have the PS-equipped 406 PLB that Louise gave me. It rides on my shoulder strap, and like was said above - it will take the "Search" out of SAR.....

Ironflight said:

I am pretty self-reliant, and have always felt that my ELT was there because the FAR's required it, and not because it would do much good....

Click to expand...

Hang out with CAP for a while and you will learn how hard it is to find a 121.5MHz ELT. OTOH, using a 406mHz unit with a built-in GPS, AFRCC will have your position very quickly indeed.

TODR

For Fee service

As some one said there are commercial services that allow you to send a message to your family with location which they can retrieve via the web. The system I am thinking of can also call emergency or police with a location message request. Its a for fee system. It would be cool to give to the wife, kid for their protection and peace of mind if you want that service. For aircraft use? not so much. Besides a 406 ELT or PLB meets the regs the other does not. The comercial vendors have devices under the names of: Spot Inc. and TracMe.

Ref http://www.equipped.org/home.htm

gmcjetpilot said:

...Besides a 406 ELT or PLB meets the regs the other does not. ...

Click to expand...

Personally I think a PLB is a great thing to carry in a GA airplane. I forgot mine the other day and felt naked. However it doesn't meet any FAA regs. The FAA doesn't care about it. Some FCC regs; yep.

even better idea!

Ron Lee said:

Is the entire country covered by these repeaters?

What will activate a search? If you are flying alone and no one is watching out for you (my case), it could be days or weeks before someone starts asking questions and realizes that you are missing.

Click to expand...

what about a system that transmits your gps position (accurately with WAAS) but instead of using ham, it uses a dedicated transponder frequency that the ATC is monitoring, it transmits your plane identification, and every plane retransmits this through a dedicated network, so the broadcast is shared by ground stations and airplanes alike. Furthermore, if your plane goes down the system has an accurate depiction and track of where you went down. Of course it is still true that if you are out of range you won't be in the broadcast, but it will have far greater range because of the inherent airborne receivers. Also the location accuracy will be an order of magnitude more accurate than current ELT technology (meters as opposed to 10s of kilometers). This track could easily be restored during search and rescue.

guess what, this describes one potential use of the ADS-B system you were knocking a couple days ago.

It isn't high tech, it is just a good idea for a standard with todays technologies. Yes it will require a more advanced transponder, but once the EFIS manufacturers start integrating the technology the price will come down below $5000.

Your letter to the FAA is a bad idea, this is one of their better ideas.

ajay

Yea your right

n5lp said:

Personally I think a PLB is a great thing to carry in a GA airplane. I forgot mine the other day and felt naked. However it doesn't meet any FAA regs. The FAA doesn't care about it. Some FCC regs; yep.

Click to expand...

You are right, I miss spoke, of course not, however its closer to an ELT (because it is an ELT) than the pay for services like Spot or TracMe. It's like flying IFR with a Garmin 496 handheld GPS, you can try it but it's not legal. A PLB is not an aircraft approved ELT, true enough. However why the FAA/FCC /GOV is screwing around, the PLB is a great adjuct, while keeping the old (121.5/243) ELT rocking a little longer.

FAA and the PLB

In their recent notice on 121.5 MHz, I believe that the FAA recommended carrying a 406 MHz PLB. Even if they did not, it makes sense.

erich weaver said:

An acquaintance of mine described an aircraft locating system that sounded promising. As I understand it, a device on the plane periodically transmits GPS coordinates on ham radio frequencies, for which there are many repeaters that can presumably be reached by a flying aircraft. The gps coordinates are automatically entered into a database with a unique identifier. The database can be accessed on the internet, thereby allowing anyone to check the last known location of a plane providing they know the identifier.

Anybody heard of this - do I have the story right? Is there a web site reference? Is this system up and running? Is the database close to real-time?Effectiveness?

erich

Click to expand...

wv4i said:

It and variations thereof are used by ham radio ops, commercial operations, police/fire/rescue, hikers, etc. For amateur radio, involves transmitting GPS position to ground based repeater linked to internet, etc. Usually used with ground vehicles, personnel, as I'm not not aware of any method to auto switch repeaters as you fly in/out range. Would work fine without switch probably within 75-200 miles of a given repeater, subject to xmtr power and receive performance at each station.

Click to expand...

I have been using APRS for weather spotting for some time. It works real well for that. Vehicles show up on the maps the National Weather Service uses so they don't have to constantly ask where everyone is.

There are big drawbacks to this system for aircraft like it has a lot of pieces and two more antennas and the system has a very low capacity because of low data rates and limited numbers of digipeaters. Also you don't know what the coverage area is.

I hadn't thought about it, until it was pointed out to me tonight, but the system Doug Reeves has been evaluating http://www.itzcomm.com/SPOT/SatelliteTrackers.html has most of the benefits without most of the drawbacks of APRS, for someone wanting that sort of thing.

For a government notification of serious trouble the PLB would still seem to be the way to go. You own it and the service is free, but it won't tell anyone where you are unless you make the major decision to activate it.

If you want someone to be able to tell where you are and how goes the trip, the Spot sounds great. It is all in one small, inexpensive package and the subscription is reasonable. It sounds like the coverage is everywhere in the US and quite of bit of other territory. Just throw it up on the glareshield.

Doug's experience suggests battery life, while transmitting, may be pretty limited. I would be interested in hearing more about that.

For me the PLB still seems like all I need, but if I was married or something like that, I'm pretty sure I would also get the SPOT.