why 406 beacons are bad

[SABRE17]

For the last 3 hours I've been listening to the search for an aircraft here on Cape Cod, I noticed that coordinates given by the aircraft's beacon were almost 10 miles from where they eventually found the pilot... the Coast Guard had several GPS coordinates that all turned out to be duds, it eventually took a citizen calling the Fire Department saying he saw debris in the water. where they eventually found the remains...

I think its safe to say Id like the hone in ability of 121.5 to save my life...

[Spaceman3750]

For the last 3 hours I've been listening to the search for an aircraft here on Cape Cod, I noticed that coordinates given by the aircraft's beacon were almost 10 miles from where they eventually found the pilot... the Coast Guard had several GPS coordinates that all turned out to be duds, it eventually took a citizen calling the Fire Department saying he saw debris in the water. where they eventually found the remains...

I think its safe to say Id like the hone in ability of 121.5 to save my life...

You still have that ability, the signal is just weaker.

[SABRE17]

allow me to direct you to the FCC attempting to get rid of the 121.5 capability

http://www.aopa.org/advocacy/articles/2012/120112elt-proposal-would-not-affect-availability.html

basically no NEW models can be made 121.5 meaning a phase out has in fact been initiated.

[Spaceman3750]

You understand that 406MHz beacons have a 121.5 homing signal transmitted at 500mW, right? The way I read this article, the FCC is trying to stop the sale of 121.5MHz-only beacons (a good thing, given that SARSAT doesn't listen for it any more), not 406 with a 121.5 homing signal.

If it only took them three hours, I'd say that's doing alright. Furthermore, the coordinates SARSAT gets is only as good as the GPS on-board the 406 (and many aren't equipped with GPS at all). Better GPS chip = better coordinates to SARSAT. No GPS chip = SARSAT takes a WAG, which is probably what was going on here.

[SABRE17]

two people died of exposure, before rescuers could get to their actual location, the coast guard helo could have been right on top of the plane if it had a 121.5 beacon...

not going to trust my life to some chip, furthermore, after being on several searches, every set of GPS coordinates we've been given, have been wrong, by a lot. 

[sardak]

allow me to direct you to the FCC attempting to get rid of the 121.5 capability
http://www.aopa.org/advocacy/articles/2012/120112elt-proposal-would-not-affect-availability.html
basically no NEW models can be made 121.5 meaning a phase out has in fact been initiated.

You've misread the change. From the FAA document:
1. This notice announces the FAA's intent to cancel TSO-C91a, Emergency Locator Transmitter (ELT) Equipment.
2. The effect of the cancelled TSO will result in no new TSO-C91a design or production approvals.
3. However, cancellation will not affect production according to an existing TSO authorization (TSOA). Articles produced under an existing TSOA can still be installed according to existing airworthiness approvals and
4. applications for new airworthiness approvals will still be processed.
5. This action does not impact operation of TSO-C91a ELTs, and these ELTs will continue to satisfy the 14 Code of Federal Regulation (14 CFR) § 91.207 ELT equipage requirement.

In other words, existing models of 121.5 MHz only ELTs can still be manufactured, sold and installed. If you want to design a new super-duper 121.5 only ELT that's never been TSO-C91a accepted, you're out of luck.

AOPA backs this proposed change and it is has been the biggest opponent to requiring 406 MHz ELTs. It is in favor of this change because the change does not require aircraft owners to replace their 121.5 beacons with 406 ones.

406 MHz ELTs are TSO'd to C-126. This TSO requires them to have a 50 to 400mW 121.5 homing signal. EPIRBs and PLBs sold in the US are also required to have a 121.5 homing signal.

If the beacon on the aircraft being searched for didn't have a 121.5 homing signal then either the beacon was faulty or it was not a model authorized for sale in the US. The Coast Guard is equipping all its aircraft and vessels with 406 DF equipment.

As for the GPS coordinates being off, that has nothing to do with the beacon, but the quality of the signal being received by the GPS in the beacon or the one connected to it externally. Not all 406 beacons have an internal or external GPS, in which case the location is Doppler determined, just like position was determined for analog, no GPS, TSO C-91a ELTs. Of course, Sarsat stopped listening to these old beacons in 2009.

As for "every set of GPS coordinates" being "wrong, by a lot," were they really GPS coordinates or were they Doppler derived locations? The Sarsat system spec states a minimum of 80% of Doppler derived coordinates are to be accurate within 20km (12 miles).

Mike

[EMT-83]

The 406 beacon got rescuers to within 10 miles of the crash site. Remember the days of 121.5 where each pass of the satellite put the signal on the other side of the state?

[TrevDog]

two people died of exposure, before rescuers could get to their actual location, the coast guard helo could have been right on top of the plane if it had a 121.5 beacon...

not going to trust my life to some chip, furthermore, after being on several searches, every set of GPS coordinates we've been given, have been wrong, by a lot.

Ok grandpa be sure to turn off your computer too and use snail mail.

All 406 MHz ELTs also have 121.5 beacon. Everything I've read through tests and actual emergency is that 406 beacons are very reliable. If a crash is so bad that the more powerful 406 MHz could only give last know position. Chances are that a 121.5 could not even be heard.

Or the Coast Guard is relying too much on the 406 gps coordinates and not even trying to DR 121.5

[RiverAux]

A three-hour find for an airplane that crashed into the water?  Seems like it would have been a miracle to find a target in that situation and I'm surprised that the beacon was transmitting anything at all. 

[Duke Dillio]

I used to live on Cape Cod BITD...  Sorry to hear that those poor souls died.

I personally think that they should have launched new SARSAT satellites instead of just abandoning the system altogether.  With today's technology, I'll bet a new SARSAT could locate the beacon, take a picture of it, and walk you right onto it...

[sardak]

personally think that they should have launched new SARSAT satellites instead of just abandoning the system altogether.

Uh, they didn't abandon the system. The most recent launch of a satellite with a Sarsat-Cospas payload was last month and there are three launches scheduled in 2012, with more beyond this year. There are currently six operational satellites in the LEOSAR (Low-Earth Orbiting) and five in the GEOSAR (Geosynchronous Earth Orbiting) systems.

The next generation system, MEOSAR, is already in development with initial operational capability planned for 2015. MEOSAR puts the Sarsat-Cospas packages on mid-Earth orbiting (MEO) navigation satellites - GPS, Galileo and Glonass. There are already nine GPS satellites in orbit with the packages undergoing test and evaluation. Return link (two-way comm) is an optional capability of MEOSAR. The US segment of this is called the Distress Alerting Satellite System (DASS).

http://searchandrescue.gsfc.nasa.gov/dass/index.html

http://www.sarsat.noaa.gov/future.html

Mike

[lordmonar]

For the last 3 hours I've been listening to the search for an aircraft here on Cape Cod, I noticed that coordinates given by the aircraft's beacon were almost 10 miles from where they eventually found the pilot... the Coast Guard had several GPS coordinates that all turned out to be duds, it eventually took a citizen calling the Fire Department saying he saw debris in the water. where they eventually found the remains...

I think its safe to say Id like the hone in ability of 121.5 to save my life...

Quite possible.....Assuming that the 406 did not have the GPS option...then the search area is a circle is 5KM (or 3 miles)...add some drift due to wind.  10 miles is not too far gone.

If it was equipted with the GPS option....it should be updating the position all the time.

Now here's the kicker.....when the equipment quits (sinks, burns, run out of power) it is gone....even if you have 121.5.

So let's look at the benifits.

Inital contact....121.5 before it was turned off...had a delay of 4-6 and up to 12 hours BEFORE they even had a fix to give to rescurers....  406...10 minutes........now that 121.5 is turned off......unless you are interfering with ATC or someone happens to be monitoring 121.5 you are screwed.

Winner?  406

Next.....121.5 gave you a 20KM radius search area.......406 gives you a 5MK radius...add GPS and you get 3 meter resolution.

Winner?  406.

False alarms......121.5 had to be seached by hand....406 can be resolved with a phone call from AFRCC.

Winner?  406.

It is a shame these people died......but the technology did not kill them.  If they were using 121.5 they would not have been better off.

[SABRE17]

Ability for ELT to be honed down to precise location:

Winner: 121.5

NO need for special equipment beyond an LPER

Winner 121.5

Ive even seen 406 beacons advertised WITHOUT the 121.5 honing ability, what's the use in that? nothing if your dying of hypothermia in the ocean while coast guard and state assets are only a mile away. (search initially started in the right area, only to be led the complete location by the magical 406 beacons GPS coordinates.)

quite frankly If you have a beacon without 121.5 capability in it somewhere, you're nuts.

keep a couple flares handy too...

[Spaceman3750]

Ability for ELT to be honed down to precise location:

Winner: 121.5

NO need for special equipment beyond an LPER

Winner 121.5

Ive even seen 406 beacons advertised WITHOUT the 121.5 honing ability, what's the use in that? nothing if your dying of hypothermia in the ocean while coast guard and state assets are only a mile away. (search initially started in the right area, only to be led the complete location by the magical 406 beacons GPS coordinates.)

quite frankly If you have a beacon without 121.5 capability in it somewhere, you're nuts.

keep a couple flares handy too...

You are certainly entitled to your opinion, however I'm not sure your opinions are based on today's operational reality.

[lordmonar]

Ability for ELT to be honed down to precise location:

Winner: 121.5

NO need for special equipment beyond an LPER

Winner 121.5

Ive even seen 406 beacons advertised WITHOUT the 121.5 honing ability, what's the use in that? nothing if your dying of hypothermia in the ocean while coast guard and state assets are only a mile away. (search initially started in the right area, only to be led the complete location by the magical 406 beacons GPS coordinates.)

quite frankly If you have a beacon without 121.5 capability in it somewhere, you're nuts.

keep a couple flares handy too...

the 406 has both of those things.  You don't really understand what the 406 is all about. 

[rustyjeeper]

Technology changes and we need to learn to accept the change. The 406 beacons do tend to leave us out of the equation which is unfortunate, especially in the area in which I live. The Coast Guard notifues local LEO's and Fire Departments but CAP was never involved. Even if we had been involved in this search, the outcome would not have changed. CAP does not and will not "self deploy" any longer as it used to long ago those days are gone. In reality if MAWG had called for a mission by the time and IC was called and teams alerted and deployed the end result would be the same.

The 406 does it's job and most of those also have the 121.5 capability; which still keeps us in business to a limited extent. Me, if I had an aircraft I would want the 406, and if I were in your shoes I would also have the 121.5 ELT as a backup just in case. Redundancy is a good thing

[lordmonar]

The 406 does it's job and mostALL of those also have the 121.5 capability; which still keeps us in business to a limited extent. Me, if I had an aircraft I would want the 406, and if I were in your shoes I would also have the 121.5 ELT as a backup just in case. Redundancy is a good thing

Fixed it for you.

[RADIOMAN015]

For the last 3 hours I've been listening to the search for an aircraft here on Cape Cod, I noticed that coordinates given by the aircraft's beacon were almost 10 miles from where they eventually found the pilot... the Coast Guard had several GPS coordinates that all turned out to be duds, it eventually took a citizen calling the Fire Department saying he saw debris in the water. where they eventually found the remains...

I think its safe to say Id like the hone in ability of 121.5 to save my life...

Some radio monitoring hobbyist reports indicate that public safety & the local CG was notified immediately when the tower/approach countrol lost contact with the aircraft.
USCG had 2 water craft, 1 Falcon Jet, & 1 Helicopter at the Scene searching.  Also the USCG Aux had a plane respond to the area. Additionally, State Environmental Police responded with at least 1 or 2 water craft.   Check the video out at:
http://www.necn.com/01/15/12/Coast-Guard-Were-just-happy-to-bring-clo/landing_newengland.html?blockID=631976&feedID=4206
Looks like the sea was not very smooth out there.   Also there were snow squalls in the area right at the time the aircraft disappeared.  Note in the video the survival time in the water without a proper insulated suit.

I don't think CAP was even alerted to provide any assistance for this response.
RM
 

[RiverAux]

Report I saw said that it crashed on the beach and if that was the case I withdraw my earlier comments.

[jpizzo127]

It's my understand that the 121.5 tone from a 406 is very weak and useless to any ground team beyond 1/2 mile.

Is this correct?

[Spaceman3750]

It's my understand that the 121.5 tone from a 406 is very weak and useless to any ground team beyond 1/2 mile.

Is this correct?

Correct; however, an aircrew should be able to put you within a reasonable distance from the target, if not right on top of it.

[lordmonar]

It's my understand that the 121.5 tone from a 406 is very weak and useless to any ground team beyond 1/2 mile.

Is this correct?

The 406 beacon gets you to withing 3KM....and then you use 121.5 to DF it to a find.

[Buzz]

Back when dinosaurs ruled the Earth, and I was a CAP cadet, the FAA came out with these fancy new radios they called "ELTs."  They were supposed to help us find downed aircraft within minutes, by screaming for help on the radio frequency which had been reserved for emergency use since the 1930s.

There was a minor problem, though -- the FAA-approved, super-flexible antennas had the annoying tendency to snap off in any impact where the ELT would be of any use.  This was eventually corrected.

Fast-forward 40 years, and now we have the 406MHz EPIRB.  This is an advanced system, which is supposed to help us find downed aircraft within minutes, by screaming for help on a radio frequency intended for monitoring by satellites.

The pros of the new system are that, when it works, it provides a faster and more accurate general fix.

The cons are that this frequency is used by many users (not just aviation), and it requires a special receiver, rarely found in aircraft, control towers, etc.  The low-power signal on 121.5 is all but worthless in most places that a plane will go down due to such factors as terrain, antenna orientation, etc -- and the antennas are tuned for 406, not 121.5. 

This means that the only people who can know that it's operating are those who either buy the special equipment, or have the frequency plugged into their scanner radios.  No more "casual" finds, where some pilot has 121.5 plugged into the B channel of his radio as he flies across the desert.  No more homing across the miles by a GT with an air-band handheld and a fox-hunt Yagi antenna.  No more multi-station fixes.  Worse, the weak signals on 121.5 will make the plane-in-a-hangar search harder, as the 406 signal punches through to the satellite but just rattles around at the airport. 

We can overcome most of these problems by changing techniques, but one problem which we CAN'T work out is that a battery running two transmitters will go dead long before that same battery if it only runs one, and as it weakens, the "homing signal" on 121.5 will go from being poor to being completely useless, in a matter of hours (at best).

One other issue is due to the vast number of users of the frequency.  Anyone who remembers their first CB walkie-talkie at Christmas will remember the joy of trying to pull your buddy's signal out from among the thousands of others on Channel 11.  Imagine the thrill of hunting for an actual missing plane or person, and discovering that the EPIRB in some nearby fisherman's tackle box has activated, is radiating into the boat's sunshade support, and has the strongest signal for miles around.  Or, worse, let's say we're looking for a plane and there are SEVERAL signals, from fishing boats, hikers' packs, kidfinders, etc, all on the same frequency.  Having a separate frequency for aviation ELTs has let us avoid this problem.

Losing 121.5 will cost us a lot of effort, a lot of money for new equipment, and possibly even cost lives.

[Buzz]

The 406 beacon gets you to withing 3KM

Yeah, it says so right on the label.

[Ed Bos]

It's my understand that the 121.5 tone from a 406 is very weak and useless to any ground team beyond 1/2 mile.

Is this correct?

Correct; however, an aircrew should be able to put you within a reasonable distance from the target, if not right on top of it.

Not to mention, that even without integrated GPS, the 406 style beacons and new SARSAT appear to get us much tighter to the actual coordinates than the old 121.5 SARSAT.  Because teams seem to be starting much closer, the lower power of the 121.5 digital tone is far from the end of the world.

And for more delicious troll food... ... The USCG can DF several 406-range beacon frequencies. There's some ok reading on this capability at http://www.sarsat.noaa.gov/BMW%2008%20attachments/USCG%20406%20Df%20presentation%202008%20BMW.pdf

[lordmonar]

I just love the nay sayers.

The frequencies might get too busy because everyone and his brother will have a a beacon of some type!.......really? 
If......IF that ever happened.....then just look at how useful CAP will be!  We will have plenty of buisness and no one would want to get rid of us!

True....it is harder to DF on 121.5.

But the probablity area is smaller and you get notified within minutes of an activation instead of hours.

Add GPS.....which I thing should be required!.....and if everything goes as plan.....SAR is going right to your location no DFing or searching required.

And once again all together for the people who did not get the memo........if you are relying on 121.5......well unless someone is monitoring it or you are close to an ATC facility.....no one is going to hear you....hope you filed a filght plan.

[EMT-83]

And do you really think that ATC is listening?

We came across an ELT signal while flying in the vicinity of a towered field last year, and reported it to ATC. Their response? "Okay, we'll turn on the radio and see if we can hear anything." Very reassuring.

[blackrain]

It's my understand that the 121.5 tone from a 406 is very weak and useless to any ground team beyond 1/2 mile.

Is this correct?

Correct; however, an aircrew should be able to put you within a reasonable distance from the target, if not right on top of it.

Not to mention, that even without integrated GPS, the 406 style beacons and new SARSAT appear to get us much tighter to the actual coordinates than the old 121.5 SARSAT.  Because teams seem to be starting much closer, the lower power of the 121.5 digital tone is far from the end of the world.

And for more delicious troll food... ... The USCG can DF several 406-range beacon frequencies. There's some ok reading on this capability at http://www.sarsat.noaa.gov/BMW%2008%20attachments/USCG%20406%20Df%20presentation%202008%20BMW.pdf

I saw one interesting statement from the report you linked. "90 percent of EPIRB SAR cases are within 20 NM of shoreline." Anyone know if that still holds true?

[SARDOC]

And do you really think that ATC is listening?

I know in my area I haven't heard ATC reporting 121.5.  They Frequently relay the message from airliners flying over.  it's really surprising how many that do get reported.

[Larry Mangum]

Back when dinosaurs ruled the Earth, and I was a CAP cadet, the FAA came out with these fancy new radios they called "ELTs."  They were supposed to help us find downed aircraft within minutes, by screaming for help on the radio frequency which had been reserved for emergency use since the 1930s.

There was a minor problem, though -- the FAA-approved, super-flexible antennas had the annoying tendency to snap off in any impact where the ELT would be of any use.  This was eventually corrected.

Fast-forward 40 years, and now we have the 406MHz EPIRB.  This is an advanced system, which is supposed to help us find downed aircraft within minutes, by screaming for help on a radio frequency intended for monitoring by satellites.

The pros of the new system are that, when it works, it provides a faster and more accurate general fix.

The cons are that this frequency is used by many users (not just aviation), and it requires a special receiver, rarely found in aircraft, control towers, etc.  The low-power signal on 121.5 is all but worthless in most places that a plane will go down due to such factors as terrain, antenna orientation, etc -- and the antennas are tuned for 406, not 121.5. 

This means that the only people who can know that it's operating are those who either buy the special equipment, or have the frequency plugged into their scanner radios.  No more "casual" finds, where some pilot has 121.5 plugged into the B channel of his radio as he flies across the desert.  No more homing across the miles by a GT with an air-band handheld and a fox-hunt Yagi antenna.  No more multi-station fixes.  Worse, the weak signals on 121.5 will make the plane-in-a-hangar search harder, as the 406 signal punches through to the satellite but just rattles around at the airport. 

We can overcome most of these problems by changing techniques, but one problem which we CAN'T work out is that a battery running two transmitters will go dead long before that same battery if it only runs one, and as it weakens, the "homing signal" on 121.5 will go from being poor to being completely useless, in a matter of hours (at best).

One other issue is due to the vast number of users of the frequency.  Anyone who remembers their first CB walkie-talkie at Christmas will remember the joy of trying to pull your buddy's signal out from among the thousands of others on Channel 11.  Imagine the thrill of hunting for an actual missing plane or person, and discovering that the EPIRB in some nearby fisherman's tackle box has activated, is radiating into the boat's sunshade support, and has the strongest signal for miles around.  Or, worse, let's say we're looking for a plane and there are SEVERAL signals, from fishing boats, hikers' packs, kidfinders, etc, all on the same frequency.  Having a separate frequency for aviation ELTs has let us avoid this problem.

Losing 121.5 will cost us a lot of effort, a lot of money for new equipment, and possibly even cost lives.

And anyone who has chased 121.5 beacons, when multiple ones are going off, also knows they mask each other, so your point about the vast numbers of users on the 406 frequency is being a new issue, is just not valid, especially since 406 beacons transmit in bursts and not continously as 121.5 beacons did.  And sicne teh 406 beacon gets you nominally with 3 km of the target it is much easier to get a read off of the 121.5 homing signal among the clutter then it is with 121.5 only beacons.

[lordmonar]

And do you really think that ATC is listening?

We came across an ELT signal while flying in the vicinity of a towered field last year, and reported it to ATC. Their response? "Okay, we'll turn on the radio and see if we can hear anything." Very reassuring.

I know my last two ELT searches were started because ATC heard the tone over their radios. (one was 121.5 and the other was 436).

So yes they are listening.....but that's okay for about 10 miles or so.  Beyond that....good luck.

[bosshawk]

Here is an interesting situation for some of you guys to chew on.  On Saturday, I replaced the battery in my 121.5 ELT, tested it with my handheld radio and closed up the airplane.  I apparently forgot to set the switch to ARM and left it on ON.  From Sat at about 1530 until Monday around 1000, not a soul heard the signal.  Somebody finally heard it Monday AM and reported it to the airport attendent(I am on a non-towered airport and the nearest tower is roughly 50 miles away).  The airport attendent, a pilot, had no idea as to whom to report it.  He knew of my CAP background and called me(I was 80 miles away).  I suggested that he take a handheld and go to my hangar, since it struck me that I might have had a brain F----.   He called back and said, yep and the local mechanic turned it off.

Now, I suspect that the battery might have finally died had everyone waited for someone else to do something about it.  The local sheriff said "OK" and hung up, as they have no DF capability.  An airway goes directly over our airport and there are several others within radio range.  The attendent did call the FAA FSDO and got a guy who was checking the weather and he said, "everybody is off today, its a holiday".  That ended the FAA participation.

I suspect that a lot of 121.5 signals get ignored just like this, with nobody monitoring them.

[Ed Bos]

The attendent did call the FAA FSDO and got a guy who was checking the weather and he said, "everybody is off today, its a holiday".  That ended the FAA participation.

That should be criminal.

[Buzz]

And anyone who has chased 121.5 beacons, when multiple ones are going off, also knows they mask each other, so your point about the vast numbers of users on the 406 frequency is being a new issue, is just not valid, especially since 406 beacons transmit in bursts and not continously as 121.5 beacons did.

While you are correct, consider that when you have multiple 121.5 signals, they all have to be found and killed anyhow.  When you have multiple 406 signals, same story, but when there were, say, 5 ELTs going off after a heavy storm or an earthquake, you will have 5 THOUSAND EPIRBS going off in the same conditions.

Consider also that the only people on 121.5 are aviation-related, while EPIRBS on 406 are being sold to a far greater number of potential users, most of whom won't have the same kind of understanding of what they are and what they are for.

Think about the ELT-in-a-flight-bag searches you've been on.  These are ALL for pilots, trained in communications and who understand the "the whole ELT thing" -- and the still forget to disarm the things when they take them out of the plane.  Now compare that to the average EPIRB purchaser.  These are generally NOT people with any technical understanding.  They buy them because they are told of all the wonderful things that an EPIRB can do for them, then handle them carelessly.  I've seen them clipped to the daypacks of kids walking to school, on the dashboards of pickup trucks, and I watched a guy at a gun show trip 10 of them, trying to find the one that had the audible tone -- while the salesman watched, made suggestions and NEVER TURNED THEM OFF (when I came around the tables and started shutting them off, they both wondered why I even cared).  As was pointed out by a different poster, this will provide job security for CAP!

The problem is that the person in REAL NEED has to compete with all of the false signals, as well as the other shortcomings.

The thing that I have against the 406 units is simply that the same advanced technology could have been added to 121.5, for less money, and still kept us away from those millions of other users.  We have been taken out of our own, special lane on the highway and shoved into rush hour with everyone else, for the convenience of government bureaucrats who have no understanding of SAR needs and capabilities.

[Buzz]

I know my last two ELT searches were started because ATC heard the tone over their radios. (one was 121.5 and the other was 436).

So yes they are listening.....but that's okay for about 10 miles or so.  Beyond that....good luck.
[/quote]

A few years ago, before SARSAT, an airline pilot went missing in his Cessna.  The word went out on company channels to every airliner in the state, who all listened on 121.5.  By the time we got to the airport, we already were getting reports of the ELT signal.  It took longer for a crew to fly to the search area than it took them to find the plane once they got there.

There's a lot to say for having beacons on a frequency that requires no special equipment to monitor.

There's a lot to say AGAINST removing a capability which saves lives, even when you think you have something better, especially when there is no valid reason to do so, much less an actual NEED to make the change.

[lordmonar]

I know my last two ELT searches were started because ATC heard the tone over their radios. (one was 121.5 and the other was 436).

So yes they are listening.....but that's okay for about 10 miles or so.  Beyond that....good luck.

A few years ago, before SARSAT, an airline pilot went missing in his Cessna.  The word went out on company channels to every airliner in the state, who all listened on 121.5.  By the time we got to the airport, we already were getting reports of the ELT signal.  It took longer for a crew to fly to the search area than it took them to find the plane once they got there.

There's a lot to say for having beacons on a frequency that requires no special equipment to monitor.

There's a lot to say AGAINST removing a capability which saves lives, even when you think you have something better, especially when there is no valid reason to do so, much less an actual NEED to make the change.

The 406's still signal on 121.5.....that has not changed.....the only difference is the power out up and how far you can receive it.

If a 406 equiped plane has gone now.....and the ELT is workign properly.....you would not have to do an "all call" sort of search.  The satellite will pick it up before the individual is even missing.  SARSAT will check the registration against any filed flight plans and will know right away if this is a real SAR or not (assuming a flight plan was filed).  If no flight plan....SARSAT makes a few phone calls if they can't get a hold of the registered owner they send it up to AFRCC as a SAR....with inital coordinates within 3Km.....all of this happens quicker then when the 121.5 was tracked by satellite.

[PHall]

Slightly Off Topic, but how many of you pilots out there monitor 121.5 when you fly?

[bosshawk]

me, on my #2 com

[peter rabbit]

our unit - using the Becker on the Aux input.

[PHall]

Now, how many "civilian" pilots do it? You would think organizations like the AOPA would be all over this.
"Monitor 121.5, you may save a life!"

I would say that this would be perfect for CAP PAO's to get out to the public. But I've seen the way many CAP PAO's go about their jobs...

[Buzz]

The 406's still signal on 121.5.....that has not changed.....the only difference is the power out up and how far you can receive it.

That difference is a MAJOR change, and it was UNNECESSARY.

The technological advances of the new ELTs are all "ahead" of the transmitter, and could have been paired with a 121.5 transmitter just as easily as pairing them with a 406 transmitter.  This one change would have ENHANCED capability, rather than reducing it.  Unfortunately for the people who will die because of that lost capability, some bureaucrat who has never been on a search for anything other than lobbyist gifts, and thinks that a "ground team" are the guys who mow his lawn, has decided how things are supposed to be done.

[Buzz]

Slightly Off Topic, but how many of you pilots out there monitor 121.5 when you fly?

Unless I need to talk to someone else, my radio is set to 121.5 because if _I_ ever need it, I don't want to have to dial it in.  I fly over an awful lot of empty desert when I'm on the mainland, and a lot of open water when I'm in Hawai'i.

I also have 121.5 as a priority monitor frequency on my scanner and on every ham rig I have that will receive it.

Back when I was growing up, the guy that taught my dad to fly ingrained this into him, asking "if you don't listen for the guy who needs you, who's going to listen for you?"

[davidsinn]

The 406's still signal on 121.5.....that has not changed.....the only difference is the power out up and how far you can receive it.

That difference is a MAJOR change, and it was UNNECESSARY.

The technological advances of the new ELTs are all "ahead" of the transmitter, and could have been paired with a 121.5 transmitter just as easily as pairing them with a 406 transmitter.  This one change would have ENHANCED capability, rather than reducing it.  Unfortunately for the people who will die because of that lost capability, some bureaucrat who has never been on a search for anything other than lobbyist gifts, and thinks that a "ground team" are the guys who mow his lawn, has decided how things are supposed to be done.

You can't transmit the data that 406's transmit on 121.5 because that is primarily a voice channel. No matter what you did you would have had to pick up a second channel to transmit the extra data.

[lordmonar]

The 406's still signal on 121.5.....that has not changed.....the only difference is the power out up and how far you can receive it.

That difference is a MAJOR change, and it was UNNECESSARY.

The technological advances of the new ELTs are all "ahead" of the transmitter, and could have been paired with a 121.5 transmitter just as easily as pairing them with a 406 transmitter.  This one change would have ENHANCED capability, rather than reducing it.  Unfortunately for the people who will die because of that lost capability, some bureaucrat who has never been on a search for anything other than lobbyist gifts, and thinks that a "ground team" are the guys who mow his lawn, has decided how things are supposed to be done.

We have not lost any capability.
The idea of going to 406 AND 121.5 is so the packet information going to the satellite is on a different freq then the GUARD voice chanel and the DF channel.

I suggest you go to the COPAS-SARSAT web page...and you will see the amount of engineering and thought went into this.

406 is better....BETTER then 121 on all accounts.....except price.

[Buzz]

You can't transmit the data that 406's transmit on 121.5 because that is primarily a voice channel. No matter what you did you would have had to pick up a second channel to transmit the extra data.

Nope, sorry, wrong answer.

A radio frequency is a radio frequency.  The only thing that changes is the payload.  APRS is digital data over a "voice channel."  Our P25 radios send digital data over "voice channels."  MODAT (the "burble-burble" ID code heard on a lot of public-safety systems) is digital data over a "voice channel."  All of the information sent by the beacon fits into a frame a fraction of a second in length, and could be sent during a periodic interruption in the ELT beacon squeal.  Since the bandwidth for data is narrower than for voice, it could even be sent on one side of the waveform, with the beacon running on the other, modulated BELOW the noise floor (as GPS does) to extend battery life.

If you have the advanced receiver, it will decode the data.  If you don't, you still have the beacon on 121.5, audible for miles and miles, with a half-second burst of data every ten seconds.  This means that existing equipment would still work as well as it ever has, and new equipment would have new features.

The 406 plan means that ONLY new equipment can be used for actually SEARCHING, with older equipment being used for pinpointing a target which as already been isolated to a small area. 

[Buzz]

We have not lost any capability.

Incorrect, Your Lordship.  A weaker signal on 121.5 means that our 121.5 equipment loses a lot of range.  We have lost the capability to pick up a signal on our existing equipment until we are much closer.  The ELT of today puts out a signal that can be picked up -- with a density sufficient for Doppler homing -- as far as 100 miles away.  The new one has a reliable radius of approximately 6.5 miles.  Doing the math, that means we've lost about 93% of our capability.

The idea of going to 406 AND 121.5 is so the packet information going to the satellite is on a different freq then the GUARD voice chanel and the DF channel.

And this does exactly NOTHING to help us.  A half-second burst of data, every 10 - 30 seconds?  What kind of problem would that pose on 121.5?  It could even be put in the head of every tone sweep, once per second, and not be in our way in the slightest.

The reason that this was done was because some fool arbitrarily decided that all emergency location was to be done on 406, rather than spending the $100 per satellite ($5 for the circuit, $95 to boost the extra two ounces to orbit) to put decoders on 121.5 and 243.0.

[lordmonar]

One reason for the freq change was so that ALL emergency beacons (marine, ground and aviation) were on the same frequency.
But your argument is kind of lame.

Even if they stuck with 121.5 as the only freq....then you would still have to buy new equipment.  Including DFers to process the digital encoded information.

End state.......exactly what we got now.  SAR agencies still needing to buy new equipment and pilots still having to buy new equipment.

Now here is the kicker.....

Unless you are an Airliner......no one is making you buy any new equipment.  AOPA successfully fought that.   

The 406's 121.5 signal is still audible for miles and miles.........just less then the old ELTs....the existing equipment STILL works.  Nothing in that respect has changed.....you can still do DF with the old Aircraft ELPER, still use VHF RDF equipment, still use wing masking....on the ground the old blue ELPER and the new orange ELPER still work.  You can still DF it with body masking.  None of that has changed.....you just have to be closer.....which the 406 signals does for you.......15KM closer and 3-4+ hours faster!......and if/when you do get the call you will not be out looking for some carrier only signal that turns out to be some defective TV tuner or a USB hard drive......because of the digital encoding.  So less false alarms, less wild goose chases for an ELT in a hanger.


Again....I still don't understand the heart burn about the new radios.  Except for the cost.....the system is better in every conceivable way.

[lordmonar]

The reason that this was done was because some fool arbitrarily decided that all emergency location was to be done on 406, rather than spending the $100 per satellite ($5 for the circuit, $95 to boost the extra two ounces to orbit) to put decoders on 121.5 and 243.0.

Yep....that's right....just because.  Forget that the fishing industry is the primary users of the SAR system......they are just some arbitrary fools.

Bottom line.....you are way to late to this argument to be bringing up "arbitary" changes as the reason why you don't like it.

Move on.

[JeffDG]

Slightly Off Topic, but how many of you pilots out there monitor 121.5 when you fly?

If you read NOTAMS, and have the capability, you are:

ALL AIRCRAFT OPERATING THE IN UNITED STATES NATIONAL AIRSPACE, IF CAPABLE, SHALL MAINTAIN A LISTENING WATCH ON VHF GUARD 121.5 OR UHF 243.0.

[CJB]

My opinion is that emergency beacons in aviation are generations behind compared to the maritime radio systems.  Why can't the aviation community upgrade to something comparable to the GMDSS, or share the same system?

Older 406 beacons chirp and can be located by their Doppler effect on SARSAT.  Unfortunately, this takes a while.  Newer 406 beacons contain GPS receivers and transmit a packet of data that identifies the ship (if programmed of course) as well as GPS coordinates.  This is why the last known position of EPIRBs is immediately sent to the Coast Guard.

[Spaceman3750]

My opinion is that emergency beacons in aviation are generations behind compared to the maritime radio systems.  Why can't the aviation community upgrade to something comparable to the GMDSS, or share the same system?

Older 406 beacons chirp and can be located by their Doppler effect on SARSAT.  Unfortunately, this takes a while.  Newer 406 beacons contain GPS receivers and transmit a packet of data that identifies the ship (if programmed of course) as well as GPS coordinates.  This is why the last known position of EPIRBs is immediately sent to the Coast Guard.

Exact same thing that's already in 406 ELTs and PLBs.

[PHall]

Slightly Off Topic, but how many of you pilots out there monitor 121.5 when you fly?

If you read NOTAMS, and have the capability, you are:

ALL AIRCRAFT OPERATING THE IN UNITED STATES NATIONAL AIRSPACE, IF CAPABLE, SHALL MAINTAIN A LISTENING WATCH ON VHF GUARD 121.5 OR UHF 243.0.

Oh, I knew about that. But how many of you know about it and actually do it?

Military aircraft have a little easier time of it because most of the UHF transceivers they use have an extra receiver built into the radio that does nothing but monitor the 243.0MHz (Guard) frequency.

Too bad they don't have something like that in civilian VHF radios...

[lordmonar]

Yes...but even on the military aircraft.....Ch+GRD is not always selected.  I know on the platform I maintain....they almost never select it except when actually doing CSAR or CSAR Training.

[PHall]

In SAC, MAC and AMC it was/is required that one radio will have the GUARD Receiver turned on at all times.
Of course we had 2 UHF, 2 VHF and 2 HF radios. :angel:

[Buzz]

One reason for the freq change was so that ALL emergency beacons (marine, ground and aviation) were on the same frequency.

And this is a good idea . . .why . . ?

But your argument is kind of lame.

Even if they stuck with 121.5 as the only freq....then you would still have to buy new equipment.  Including DFers to process the digital encoded information.

No, _I_ would not have to buy new equipment.  I don't need the information carried in the digital burst, all _I_ need is to be able to hear the beacon and get a fix.  I wouldn't have to spend a penny more to do that, if not for them putting aircraft ELTs on the same frequency as every kid with a backpack beacon.

End state.......exactly what we got now.  SAR agencies still needing to buy new equipment and pilots still having to buy new equipment.

Sorry, I refuse to accept your straw man as the baseline.

Now here is the kicker.....

Unless you are an Airliner......no one is making you buy any new equipment.  AOPA successfully fought that.   

The 406's 121.5 signal is still audible for miles and miles
[/quote]

The new specification is for a 121.5 "supplemental signal" of 0.025 watts -- one fourth of the current 0.1 watt average output of ELTs.  That gives a maximum unobstructed and reliable useful range of about 5 - 7 miles at 121.5MHz, A3E modulation, compared to 30 - 50 miles at 0.1W.  Doubling that for best-case scenario give you 10 - 15 miles on the new unit, 60 - 100 miles on the current one

you just have to be closer.....which the 406 signals does for you.......15KM closer and 3-4+ hours faster!

The "406" part is the only complaint that I have.  If they had added this system to 121.5 ELTs, I would welcome it with open arms.  The only reason they chose to make the change was so that all beacons would be on the one frequency, like when all the kids in town got their Christmas CB walkie-talkies on Channel 11.  True, most SAR agencies would be buying 406 equipment anyway, to find EPIRBS, but the vast majority of locator equipment used in SAR for aircraft is bought and paid for by individuals, not by agencies.  Tests have repeatedly shown that the 406 beacon digital "fix" tolerance is significantly greater than the range of the 121.5 "supplemental" signal.  Some manufacturers of the new ELTs have opted to pair full-power 121.5 transmitters with the 406 transmitters because of this deficiency, but having two transmitters boosts battery drain (even though the 406 transmitter sends short bursts, they are also 5 watts, so drain is about the same as the 100 milliwatt constant squeal).

Sure, batteries are better now than they used to be, but if they had put the data burst on 121.5 there would be only one transmitter, thus longer operating time than powering two complete transmitters.

[Buzz]

Bottom line.....you are way to late to this argument to be bringing up "arbitary" changes as the reason why you don't like it.

Move on.

No, the bottom line is that we have lost a capability that is used to save lives, and it has been removed arbitrarily and unnecessarily, when the new stuff could have easily been ADDED.

But what the heck, I've only been doing SAR and communications since the early 1970s, both in CAP and professionally, so it's not like I actually know anything about it, compared to an expert such as yourself.

[Extremepredjudice]

if/when you do get the call you will not be out looking for some carrier only signal that turns out to be some defective TV tuner or a USB hard drive......because of the digital encoding.  So less false alarms, less wild goose chases for an ELT in a hanger..

how does a TV tuner or a USB hard drive send a radio signal? Just wonderin'

[RiverAux]

True, most SAR agencies would be buying 406 equipment anyway, to find EPIRBS, but the vast majority of locator equipment used in SAR for aircraft is bought and paid for by individuals, not by agencies. 

What?  I'd like to see some evidence to back that up.  While I'm sure there are a few personal DF units out there in CAP, I've never seen one in two wings in 15 years.  And if you're not talking about CAP, I'd like to know what group of individuals is doing missing airplane searches with personal DF equipment and that collectively have bought more DF equipment than CAP and a host of state and federal agencies combined. 

[Duke Dillio]

True, most SAR agencies would be buying 406 equipment anyway, to find EPIRBS, but the vast majority of locator equipment used in SAR for aircraft is bought and paid for by individuals, not by agencies. 

What?  I'd like to see some evidence to back that up.  While I'm sure there are a few personal DF units out there in CAP, I've never seen one in two wings in 15 years.  And if you're not talking about CAP, I'd like to know what group of individuals is doing missing airplane searches with personal DF equipment and that collectively have bought more DF equipment than CAP and a host of state and federal agencies combined. 

I have my own DF and I know two others in this wing who have their own as well.  I can give you the name of a group that was doing missing airplane/ELT searches with personal equipment but that haven't collectively bought more than CAP and the other agencies.  In fact, one member of my wing in particular has run into these yahoos more than three or four times.

http://www.pacifier.com/~nwelt/index.html

Don't know if they are still around but it is my understanding that they were a group of disgruntled CAP members who went out on their own.  That is my understanding anyways...

[lordmonar]

One reason for the freq change was so that ALL emergency beacons (marine, ground and aviation) were on the same frequency.

And this is a good idea . . .why . . ?

So the SAR agencies....only have to monitor one freq and only have to buy on set of equipment for all three type of ELT ememgencies. 

But your argument is kind of lame.

Even if they stuck with 121.5 as the only freq....then you would still have to buy new equipment.  Including DFers to process the digital encoded information.

No, _I_ would not have to buy new equipment.  I don't need the information carried in the digital burst, all _I_ need is to be able to hear the beacon and get a fix.  I wouldn't have to spend a penny more to do that, if not for them putting aircraft ELTs on the same frequency as every kid with a backpack beacon.

And you still have that function...nothing has changed.  THEY changed the ELT equipment and YOU still have the ability to idlely monityory 121.5 and report any signal hits.  You can still DF with your old stlye DF equipment, and you can still DF using body blocking methods with your on board NAVCOM radios.   Once again......other then signal strenght....nothing has changed for YOUR point of view.

End state.......exactly what we got now.  SAR agencies still needing to buy new equipment and pilots still having to buy new equipment.

Sorry, I refuse to accept your straw man as the baseline.

Not a staw man.....fact.  You are lamenting that YOU (as a Layperson Pilot) had to change equipment....but the bottom line is that the professional SAR agecies (which I include CAP into) are the only one's who count in this case....and of course the victums.....The increased reliabilty, unique signals, the digital encoding all equate to FASTER and more ACCURATE inital SAR information.  Something on the order of 3-6 hours faster and withing 5KM of the target instead of 20KM.  THAT IS SAVING LIVES!  Add the benifit of not having to chase a bunch of false alarms around.....

Now here is the kicker.....

Unless you are an Airliner......no one is making you buy any new equipment.  AOPA successfully fought that.   

The 406's 121.5 signal is still audible for miles and miles

The new specification is for a 121.5 "supplemental signal" of 0.025 watts -- one fourth of the current 0.1 watt average output of ELTs.  That gives a maximum unobstructed and reliable useful range of about 5 - 7 miles at 121.5MHz, A3E modulation, compared to 30 - 50 miles at 0.1W.  Doubling that for best-case scenario give you 10 - 15 miles on the new unit, 60 - 100 miles on the current one

Yep.....and?  On the old system you would be given an intial coordinate after 3-6 hours of the ELT activation with a search radius of 20Km.   Now you get an intial coordinate within 10 minutes with a search radius of 5Km.  The 121.5 signal is only included for the "terminal DF search" any ways.  It is not for intial notification, it is not for "I was crusing at FL300 and heard a signal"....it is for us to use the old DF equipment to find the ELT.

you just have to be closer.....which the 406 signals does for you.......15KM closer and 3-4+ hours faster!

The "406" part is the only complaint that I have.  If they had added this system to 121.5 ELTs, I would welcome it with open arms.  The only reason they chose to make the change was so that all beacons would be on the one frequency, like when all the kids in town got their Christmas CB walkie-talkies on Channel 11.  True, most SAR agencies would be buying 406 equipment anyway, to find EPIRBS, but the vast majority of locator equipment used in SAR for aircraft is bought and paid for by individuals, not by agencies.  Tests have repeatedly shown that the 406 beacon digital "fix" tolerance is significantly greater than the range of the 121.5 "supplemental" signal.  Some manufacturers of the new ELTs have opted to pair full-power 121.5 transmitters with the 406 transmitters because of this deficiency, but having two transmitters boosts battery drain (even though the 406 transmitter sends short bursts, they are also 5 watts, so drain is about the same as the 100 milliwatt constant squeal).

Sure, batteries are better now than they used to be, but if they had put the data burst on 121.5 there would be only one transmitter, thus longer operating time than powering two complete transmitters.

So your REAL problem is that we have share......or more appropriate we have change to share someone elses' frequency.

[lordmonar]

Bottom line.....you are way to late to this argument to be bringing up "arbitary" changes as the reason why you don't like it.

Move on.

No, the bottom line is that we have lost a capability that is used to save lives, and it has been removed arbitrarily and unnecessarily, when the new stuff could have easily been ADDED.

But what the heck, I've only been doing SAR and communications since the early 1970s, both in CAP and professionally, so it's not like I actually know anything about it, compared to an expert such as yourself.

So....if you were such an expert....why did they just ignore your wisdom? 
Dude....I can do the Ad Homins too.

Let's agree to disagree okay?

[Buzz]

if/when you do get the call you will not be out looking for some carrier only signal that turns out to be some defective TV tuner or a USB hard drive......because of the digital encoding.  So less false alarms, less wild goose chases for an ELT in a hanger..

how does a TV tuner or a USB hard drive send a radio signal? Just wonderin'

A TV tuner receives the over-the-air frequency, then converts it to an "intermediate frequency" (or sometimes more than one), the same as your satellite TV box.

A computer operates at several different radio frequencies.  A USB drive can act as an antenna for the frequency which it's operating on, and most are pretty much unshielded.

[Buzz]

So....if you were such an expert....why did they just ignore your wisdom? 

They ignored the wisdom of several hundred people wiser than I, who wrote and testified on the subject during the (brief) decision-making period.

Let's agree to disagree okay?

The ONLY place that we disagree is on the FREQUENCY.

Consider 406 to be Beacon Superhighway, the beautiful, smooth new 21-century 8-lane with onramps and offramps for everyone.  Compare this to Route 121.5, ELT Road, the four lanes laid down in the 1940s, with dips and the occasional pothole.  This decision takes most of the traffic from Route 121.5 and puts it onto Beacon Highway, with every other user in the world, simply because it saves a couple of thousand dollars for the Highway Department.

When you had a flat on Route 121.5, the tow truck from the nearest town would come out and find you, often assisted by the local hot rod club.  If you get the same flat on Beacon, the Freeway Authority Recovery System is the only resource.  They promise to give you faster service, but they are the only game in town. 

There is no reason, technologically, to put all traffic onto Beacon.  Anyone who has ever worked with digital communications will tell you that there are several major reasons that a 406 beacon might be operating properly but doing no good.  A burst of static that trashes the first part of a data frame will result in the entire frame being disregarded.  Likewise a collision between multiple frames from different transmitters.

In computer networking, an acknowledgment is sent from the recipient to the sender -- if it isn't received the frame is sent again.  In the 406 system, there is only one-way error checking (a checksum in the data frame).  This is fine, if yours is the only signal being sent, and the weather is good.

Planes don't crash unless the weather is good . . .right? 

By putting the digital on 121.5, the chance of frame collision is miniscule compared to putting it on 406 with the massive number of accidental activations, lost kids, out of gas backcountry Jeepers, hikers, etc.

Of course, we should be involved in some of those searches, but the ideal would be a separate beacon frequency for each person in need, with second best being a frequency for each TYPE of users (aviation, kids, hikers, boaters etc), the same as an idea highway would give each vehicle its own lane (with second best being bus lanes, truck lanes, car lanes, etc).  Instead, we have Radio Rush Hour, with all of the possible nasty scenarios, and the Highway Department wants to make it the ONLY ROAD IN TOWN, reducing Route 121.5 to a bike path.

[Extremepredjudice]

if/when you do get the call you will not be out looking for some carrier only signal that turns out to be some defective TV tuner or a USB hard drive......because of the digital encoding.  So less false alarms, less wild goose chases for an ELT in a hanger..

how does a TV tuner or a USB hard drive send a radio signal? Just wonderin'

A TV tuner receives the over-the-air frequency, then converts it to an "intermediate frequency" (or sometimes more than one), the same as your satellite TV box.

A computer operates at several different radio frequencies.  A USB drive can act as an antenna for the frequency which it's operating on, and most are pretty much unshielded.

What! Stop making stuff up sir!

I'm not an expert on TV tuners, but they transmit it via CABLE.

The USB drive thing is hogwash.

[Buzz]

True, most SAR agencies would be buying 406 equipment anyway, to find EPIRBS, but the vast majority of locator equipment used in SAR for aircraft is bought and paid for by individuals, not by agencies. 

What?  I'd like to see some evidence to back that up.  While I'm sure there are a few personal DF units out there in CAP, I've never seen one in two wings in 15 years.  And if you're not talking about CAP, I'd like to know what group of individuals is doing missing airplane searches with personal DF equipment and that collectively have bought more DF equipment than CAP and a host of state and federal agencies combined.

Reread -- my fault for not making myself more clear -- and you will see that I mean equipment used for SAR INVOLVING aircraft, not equipment IN aircraft used for SAR.

You're thinking Doppler gear.  I'm thinking aircraft radios, HTs, radio scanners, etc., not only those used by CAP but also by other aviators or volunteers.  Now all of those resources are going to be rendered less effective -- most to the point of uselessness.

"For lack of a nail, a shoe was lost . . ."
 

[JetDriver777]

Ok mr know it all
"Buzz". 406 dosent use just one freq .  There
Are now 10+ freqs being used to send the data. Since 406 only can be used for distress data
Communicatiins the likely hood that the data will get to the bird is much greater than also having voice on the same freq like 121.5.

But you already know that!

It amazes me how little cap folks know about the system that they supposedly interface with every day!

[PHall]

Ok mr know it all
"Buzz". 406 dosent use just one freq .  There
Are now 10+ freqs being used to send the data. Since 406 only can be used for distress data
Communicatiins the likely hood that the data will get to the bird is much greater than also having voice on the same freq like 121.5.

But you already know that!

It amazes me how little cap folks know about the system that they supposedly interface with every day!

So sayeth Mr Anonymous. And your bonefides are what?

[JetDriver777]

Well I'm not an old crotchety fart that knows everything there is to know " becouse I've been around since the 70's"

So you are
Stuck in the old days, and for whatever reason don't like the 406 system.  WHO CARES? You don't like the freq so it's bad? BuzzThe new self proclamed master on RF has spoken!  The FCC and FAA are Morons now because they didn't talk to Buzz first!

And we wonder why knowbody takes CAP seriously!

[Buzz]

if/when you do get the call you will not be out looking for some carrier only signal that turns out to be some defective TV tuner or a USB hard drive......because of the digital encoding.  So less false alarms, less wild goose chases for an ELT in a hanger..

how does a TV tuner or a USB hard drive send a radio signal? Just wonderin'

A TV tuner receives the over-the-air frequency, then converts it to an "intermediate frequency" (or sometimes more than one), the same as your satellite TV box.

A computer operates at several different radio frequencies.  A USB drive can act as an antenna for the frequency which it's operating on, and most are pretty much unshielded.

What! Stop making stuff up sir!

I'm not an expert on TV tuners, but they transmit it via CABLE.

The USB drive thing is hogwash.

The only part of what you wrote that is true is that you're not an expert.

I dunno where you live, but I'm sure that if you look around, you'll see a little bitty round thing on someone's house, with "DISH" or "DirecTV" written on it.  This picks up microwave radiation, and downconverts it to a freqency that your TV can use.  If you look a little farther, on a mountaintop or a tall building, you will find a big tall Erector-set kind of stick thingy, probably painted red and white.  There is a highly-technical term used to describe this -- we electronics folks tall this an "antenna tower."  Stay with me now, this gets pretty technical, but things called "over the air television signals" are transmitted from these.

Neither of these is "transmitted via CABLE." 

Did you sleep through the whole "HDTV transition" thing?  This only affects over-the-air broadcasting, NOT TV sets hooked up to cable.

And if you don't know that a computer and USB interface pump out RF interference, you might want to study the issue before you decide that it's "hogwash."  Try this article from Compliance Engineering Magazine, (http://www.ce-mag.com/archive/1999/julyaug/usb.html).  Or you can do what I do, and use a spectrum analyzer to sweep around computers to chart the electromagnetic footprint (required by one of my clients, who is involved in radioastronomy and satellite communications).

[lordmonar]

The USB drive thing is hogwash.

I tracked a carrier only 121.5 signal to a house in Las Angeles...it was comming from a USB MP3 stoage unit plugged into a computer.

Unsheilded cables with a dirty motor or frequency generator can make all sorts of noise. 

[RiverAux]

True, most SAR agencies would be buying 406 equipment anyway, to find EPIRBS, but the vast majority of locator equipment used in SAR for aircraft is bought and paid for by individuals, not by agencies. 

What?  I'd like to see some evidence to back that up.  While I'm sure there are a few personal DF units out there in CAP, I've never seen one in two wings in 15 years.  And if you're not talking about CAP, I'd like to know what group of individuals is doing missing airplane searches with personal DF equipment and that collectively have bought more DF equipment than CAP and a host of state and federal agencies combined.

Reread -- my fault for not making myself more clear -- and you will see that I mean equipment used for SAR INVOLVING aircraft, not equipment IN aircraft used for SAR.

You're thinking Doppler gear.  I'm thinking aircraft radios, HTs, radio scanners, etc., not only those used by CAP but also by other aviators or volunteers.  Now all of those resources are going to be rendered less effective -- most to the point of uselessness.

No, I think I understood and you still don't have a leg to stand on.  Yes, there is some private gear used for searches involving airplanes, but there is no way in heck there is more of that which has been purchased by private individuals than public agencies and CAP.  No one is more involved in missing airplane search than CAP and there certainly aren't many private individuals buying equipment to locate them. 

[Buzz]

Ok mr know it all
"Buzz". 406 dosent use just one freq .  There
Are now 10+ freqs being used to send the data. Since 406 only can be used for distress data
Communicatiins the likely hood that the data will get to the bird is much greater than also having voice on the same freq like 121.5.

But you already know that!

It amazes me how little cap folks know about the system that they supposedly interface with every day!

Go read the latest Channel Assignment Table.  Those "10+ freqs being used" are actually FOUR "being used," and are aging out, the same way our radios have aged out due to NTIA transition schedules.  One is only for firstgen beacons, designed before 2002 and made until the end of 2006.  Two others offered a production window averaging 7 years.  ONLY ONE is available for beacons approved after January of this year (this window has already been open for two years, with tens of thousands of units produced), and will include the aviation ELT replacements.

There are several RESERVED frequencies, but they are not in use and no projected operational date has been released to the beacon manufacturers.  Following current pattern, this production window will be for the next 5 years, and ALL beacons not currently approved will use this ONE frequency.

[Buzz]

No, I think I understood and you still don't have a leg to stand on.  Yes, there is some private gear used for searches involving airplanes, but there is no way in heck there is more of that which has been purchased by private individuals than public agencies and CAP.  No one is more involved in missing airplane search than CAP and there certainly aren't many private individuals buying equipment to locate them.

If YOU have bought any radio equipment for use on 121.5, that is "individually purchased."  Every radio in every non-corporate plane flown by CAP on a search is "individually purchased."  Every radio tuned to 121.5 by someone flying somewhere in their private plane is "individually purchased."  Unless you want to claim that CAP and other official agencies have bought more of these radios than have all of these other users, I'd say that I'm standing pretty solidly.

[RiverAux]

Every radio in every non-corporate plane flown by CAP on a search is "individually purchased." 

Basically, that system hasn't existed for 20 year or more.  In those extremely rare situations where a non-CAP plane is flown by a CAP member on a CAP mission its going to be used for transport and isn't going to be out flying a grid and other their radio ain't going to be used for anything other than comm. 

[Buzz]

Well I'm not an old crotchety fart that knows everything there is to know " becouse I've been around since the 70's"

Neither am I.

I'm a crotchety old fart that knows everything there is to know because I've been DOING these things since the '70s. 

This is why I stay anonymous out here in cyberspace -- I know a lot of people, in a lot of different fields, and don't want someone doing a web search on my name to know that I'm in CAP (or any of the other things I'm involved with) unless I have chosen to tell them.  It's a lot easier for me to get my consulting fees when clients can't just look up my comments to others and extrapolate from them. 

This crotchety old fart recently was asked by a company to reverse engineer a patented device, because they don't want to deal with the one company which currently holds the license for the original.  I succeeded, and will make not only the original contract amount, but got a performance bonus for bringing it in so quickly, and I hold the patent on the new device.  It actually cost them more to have it reverse engineered than to have bought it from their competitor, and the patent holder would have made a fraction of what I got for doing the project.

In effect, I got paid twice for the same work because the people who hired this this crotchety old fart couldn't just go online and see that I'm the same crotchety old fart who holds the patent on the original.

People pay me a lot of money for what I know.  CAP is my way of giving back to the country, but they might not understand.  I'm sorry that I come off as a smartass, but at least I'm a COMPETENT smartass.  After one launch several years back, at the debrief I noted that, of the 100 or so people there, I had offended probably half.  I apologized to the rest for not having had enough time to rub them the wrong way, too.  I get frequent calls from people that I've irritated over the years, so I have to say that I really MUST be good at what I do, or they wouldn't want repeat engagements.

[Buzz]

Every radio in every non-corporate plane flown by CAP on a search is "individually purchased." 

Basically, that system hasn't existed for 20 year or more.

Not quite true.  The capability is still "on the books" even in areas where all SAR is corporate.

In those extremely rare situations where a non-CAP plane is flown by a CAP member on a CAP mission its going to be used for transport and isn't going to be out flying a grid and other their radio ain't going to be used for anything other than comm.

Also not quite true, but an argument for another time.

[SarDragon]

if/when you do get the call you will not be out looking for some carrier only signal that turns out to be some defective TV tuner or a USB hard drive......because of the digital encoding.  So less false alarms, less wild goose chases for an ELT in a hanger..

how does a TV tuner or a USB hard drive send a radio signal? Just wonderin'

Almost all receivers - radio, TV, radar, you name it - have one or more local oscillators, which can, under the right circumstances, radiate a signal. These signals can cause interference on various frequencies. Sometimes the interference shows up as a carrier-only signal on 121.5, and steps on other transmissions.

Computers also have oscillators that can cause similar problems.

[CJB]

if/when you do get the call you will not be out looking for some carrier only signal that turns out to be some defective TV tuner or a USB hard drive......because of the digital encoding.  So less false alarms, less wild goose chases for an ELT in a hanger..

how does a TV tuner or a USB hard drive send a radio signal? Just wonderin'

Almost all receivers - radio, TV, radar, you name it - have one or more local oscillators, which can, under the right circumstances, radiate a signal. These signals can cause interference on various frequencies. Sometimes the interference shows up as a carrier-only signal on 121.5, and steps on other transmissions.

Computers also have oscillators that can cause similar problems.

Seems like the skeptics on here aren't too familiar with intermod distortion.  An offending device doesn't have to operate on 121.5MHz to cause interference on that frequency.

[SarDragon]

Here's another example - I can tune a cheap FM radio to a freq 10.7 MHz away from specific TV channels, and totally screw up the TV audio. RF emissions are strange things to work with.