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elt antenna

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icubob(at)newnorth.net
Guest

Posted: Sun May 28, 2006 5:27 am Post subject: elt antenna

hi all, this topic was recently discussed on another list. timely as i =

was installing my elt. a few facts came out of the discussion

 1]  elts fail to function in over 90% of accidents

 2] no matter where you mount an elt you have no control how the =

airplane will come to rest in a crash...upside down, right side up, on =

its nose.

 3] the best insurance for a quick recovery is filing a vfr flight plan =

if you can.

 after the discussion i quit losing sleep about where to put my elt =

antenna.



                          bob noffs

nuckollsr(at)cox.net
Guest

Posted: Sun May 28, 2006 7:01 am Post subject: elt antenna

At 08:11 AM 5/28/2006 -0500, you wrote:



 	  Quote: 	
		  



hi all, this topic was recently discussed on another list. timely as i =

was installing my elt. a few facts came out of the discussion

  1]  elts fail to function in over 90% of accidents


	


   I read a piece some time ago . . . I think in AOPA Pilot.

   The stats on ELT effectiveness were discussed. I'm think I'm

   recalling that the data being studied was for all ELTs which

   included a large population of the earliest 121.5, carrier

   plus modulation suitable only for aural i.d. of a beacon.

   The numbers were NOT encouraging.



   It's true that the earliest systems were hampered by the

   inability of a satellite system's rudimentary position

   calculation system to get a location on the beacon.

   It took multiple passes of satellites and some calculation

   to get a rough idea of where to look for you. Read HOURS



   ELT's are now available that report your GPS position

   so that your location is known upon first detection of

   the signal. The advantages of this feature are obvious.

   If ANY ELT is installed, I'd use one with the GPS reporting

   feature.



   Even without the reporting feature, ELT locating hardware

   and software is much more sophisticated. Your location

   is likely to be deduced in minutes and with much greater

   accuracy.



 	  Quote: 	
		    2] no matter where you mount an elt you have no control how the =

airplane will come to rest in a crash...upside down, right side up, on =

its nose.


	


    True . . . but being upside down is not an automatic

    turn-off of the ELT's ability to transmit. Remember,

    we're talking line of sight transmission where very

    small transmitters and relatively inefficient antennas

    are able to cross the gap. It's more important that the

    antenna and transmitter remain INTACT than to worry

    about perfect positioning. This is why a location in

    front of the vertical fin was chosen . . . for the

    any benefits that the fin structure might offer in

    keeping the antenna from being broken off.



 	  Quote: 	
		    3] the best insurance for a quick recovery is filing a vfr flight plan =

if you can.


	


    Every little bit helps. Having someone watch

    to see if you arrive at the expected time and location

    is yet another layer of risk mitigation . . . but simply

    knowing that you're not at the appointed place at the

    appointed time is a small piece of a huge puzzle.



    Having a beacon broadcasting your location to the world

    with a accuracy of a few meters is about the best risk

    mitigator we have in the current tool box.



    I would also carry a hand held and plenty of spare

    batteries. In the US at least, there are dozens of

    aircraft within your line of sight location at any

    given time. If I ran the FAA, I'd allocate a second

    emergency frequency, SEPARATE from 121.5 as a CRASHCOM

    service. Alerts for missing aircraft could be put out

    not unlike the Amber Alerts for missing children. If

    any en route air transport category airplane within

    150 miles of your location is listening, you'll be

    able to talk to them from your hand-held. Having a hand

    held GPS to back up your ELT's ability to report position

    is a good thing to have too.



    Bob . . .

craig(at)craigandjean.com
Guest

Posted: Sun May 28, 2006 11:32 am Post subject: elt antenna

As best I can tell feeding GPS coordinates into the new generation of ELTs

is a *very* expensive proposition - at least when sticking to Artex's

products. First you have to switch from their "cheap" model ME406 to the

G406 to get a unit which accepts GPS coordinates ($1456 vs. $839). Then you

have to buy their Nav/ELT interface box (455-6500), about $1358). And (from

what I can make out from the specs) the interface box only accepts serial

data in the form sent by expensive in-panel GPS receivers, not the NMEA 0183

format from cheap portable units.



The alternative is to buy a Personal Locator Beacon like the McMurdo

Fastfind. The model with a GPS built-in costs $573. But a PLB is manually

triggered, not by a G sensor. So it doesn't do any good if you are

unconscious. I live in the mountainous west where there are lots of out of

the way places to crash. I guess I can rationalize buying a PLB by saying

that if I remain unconscious too long to activate the PLB then I'll probably

be dead by the time I am rescued. The PLB would just get me found faster

after a crash where I am in relatively good shape.



-- Craig

rv8ch

Joined: 10 Jan 2006
Posts: 250
Location: Switzerland

Posted: Sun May 28, 2006 12:39 pm Post subject: elt antenna

 	  Quote: 	
		   ...  But a PLB is manually

 triggered, not by a G sensor. So it doesn't do any good if you are

 unconscious. ...


	


Couldn't you activate the PLB before you hit the ground, and hope it

survives the impact?



-- 

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

do not archive

_________________
Mickey Coggins
http://www.rv8.ch/

craig(at)craigandjean.com
Guest

Posted: Sun May 28, 2006 2:36 pm Post subject: elt antenna

I suppose I could but I'd be concentrating on flying the plane gracefully

into the ground 



These are hand-held units so I guess you would also want to toss it clear of

the plane. Also they are designed to be hard to (accidentally) trigger.



Maybe I'll install a ballistic recovery chute or move to someplace flat like

Kansas.



-- Craig 



--

gmcjetpilot(at)yahoo.com
Guest

Posted: Mon May 29, 2006 1:11 am Post subject: elt antenna

Here is why ELT's exist (first par): 

http://www.wsdot.wa.gov/aviation/SAR/ELT_History.htm

   

  The rest is extremely interesting and highlights the state of 

confusion with the new 406 ELT's. You may be able to use

your old 121.5/243 ELT after Feb 2009 but it may be even 

less effective than it's today. Clearly the 406 ELT can get 

your position within a mile or two to 100 yards with GPS.

 

  Faults alarms where addressed with TSO-C91a  (verse the old C91)  

  http://www.avionicswest.com/myviewpoint/boringarticle.htm

 

The newer TSO ELTs require small annunciator/control 

panel to be installed somewhere in the cabin and provide a 

visual indication via a blinking light when the ELT is 

activated and of course, turn off the ELT if need be. 

However the wsdot article says many ELT faults alerts 

are not even from ELT's!

 

The avionicswest article mentions the new PLB's as 

others have mentioned. I agree there awesome devices 

many should consider as a backup, especially if you are 

into outdoor sports of any kind. I remember stories of 

people going off the side of the road and not being 

found for many days just feet from a major freeway, hurt 

but alive. Many PLB's have built in GPS position!

   

  What I hear and  read the 2009 deadline may be extended. 

That's not a good thing since the satellites WILL? still stop 

monitoring 121.5/243 regardless!  AOPA is asking for a 

voluntary replacement program.  Reading the advantage 

of 406 ELT's it seems like a no brainier? 

   

  Before the satellites monitored for ELT's in the 70's ELT 

location method was with local DF only. Lets say 406 ELTs 

are not made mandatory. With out the satellites your 

chance of being found with old fashion DF is slim to none.

   

George

   

   



 __________________________________________________

rv8ch

Joined: 10 Jan 2006
Posts: 250
Location: Switzerland

Posted: Mon May 29, 2006 2:44 am Post subject: elt antenna

 	  Quote: 	
		     What I hear and  read the 2009 deadline may be extended. 

 That's not a good thing since the satellites WILL? still stop 

 monitoring 121.5/243 regardless!  AOPA is asking for a 

 voluntary replacement program.  Reading the advantage 

 of 406 ELT's it seems like a no brainier? 

    

   Before the satellites monitored for ELT's in the 70's ELT 

 location method was with local DF only. Lets say 406 ELTs 

 are not made mandatory. With out the satellites your 

 chance of being found with old fashion DF is slim to none.


	


I can argue both sides of the mandatory ELT issue.  With

my Libertarian hat on, I think it should be up to the builder

to decide if they want a PLB/ELT in their aircraft, and

they have to live (or die) with the consequences.  The

problem comes in when there are unwary passengers on the

aircraft, and/or public resources are used to try to find

the downed aircraft.



Of course, we could simply say that if you don't have a

PLB/ELT, then you need to placard this for passengers,

and if there is a search and rescue launched to recover

your body, then your spouse/estate will get billed for the costs.



Putting on the Statist hat (I don't have one - I'd have to

borrow it), if PLB/ELT devices are required, then they

will end up costing less, and search and rescue missions

will probably also cost less and be more effective.  We

may even find a survivor or two.



I fly with an ELT simply because I am required to do so,

and I plan to upgrade to a PLB "soon", but I wouldn't

want to impose my choices on anyone else.



-- 

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

do not archive

_________________
Mickey Coggins
http://www.rv8.ch/

BobsV35B(at)aol.com
Guest

Posted: Mon May 29, 2006 4:46 am Post subject: elt antenna

In a message dated 5/29/2006 5:46:30 A.M. Central Standard Time,  

mick-matronics(at)rv8.ch writes:



I fly  with an ELT simply because I am required to do so,

and I plan to upgrade to  a PLB "soon", but I wouldn't

want to impose my choices on anyone  else.



Me Too 

(Sorry Matt, I just couldn't resist!)

 

Do Not Archive

 

Happy  Skies,



Old Bob

AKA

Bob Siegfried

Ancient Aviator

Stearman  N3977A

Brookeridge Air Park LL22

Downers Grove, IL 60516

630  985-8503

nuckollsr(at)cox.net
Guest

Posted: Mon May 29, 2006 6:26 am Post subject: elt antenna

At 01:26 PM 5/28/2006 -0600, you wrote:



 	  Quote: 	
		  

<craig(at)craigandjean.com>



As best I can tell feeding GPS coordinates into the new generation of ELTs

is a *very* expensive proposition - at least when sticking to Artex's

products. First you have to switch from their "cheap" model ME406 to the

G406 to get a unit which accepts GPS coordinates ($1456 vs. $839). Then you

have to buy their Nav/ELT interface box (455-6500), about $1358). And (from

what I can make out from the specs) the interface box only accepts serial

data in the form sent by expensive in-panel GPS receivers, not the NMEA 0183

format from cheap portable units.


	


   Here's an opportunity for some of you byte thrashers out there.

   A $1 PIC microcontroller and a handful of jellybean parts could

   probably be crafted to convert NMEA 0183 into the golden format.

   GPS engines are about $50 each. You could craft a stand-alone

   GPS enhancement adapter for the bare-bones GPS capable ELT.



   Bob . . .

w_sweet(at)comcast.net
Guest

Posted: Mon May 29, 2006 10:30 am Post subject: elt antenna

I feel much the same as Bob Nuffs. However I NEVER file an VFR flight =

plan. UHHHH...... OOOOHHHH

I ALWAYS use flight following and have been refused service rarely and =

only in high density areas around Class B airspace. If one has a problem =

while under radar contact, you get immediate assistance in the form of =

radar vectors if needed.  AND more importantly, they know precisely =

where you are. Only in very mountainous situations is radar contact =

lost, but at least the area of crash landing is known. Too many =

searches, when there is one, begin searching nearly a whole state. More =

important than that is the search will be put in motion right then at =

the time of radar contact lost. ATC can even be an aid in vectoring =

search aircraft to the general area.=20

ELT's need a quantum jump is technology to provide the needed =

information and reliability to be truly useful.

Wayne

Bill Schlatterer

Joined: 09 Jan 2006
Posts: 195

Posted: Mon May 29, 2006 11:19 am Post subject: elt antenna

Mickey, I think the PLBs are a better option as well but have not seen any

data on them in actual use.  Do you have any info that would suggest that a

PLB signal is more likely to be received than a ELT if the PLB is inside an

upside down metal aircraft ??  (typical Vans) Would the burst signal that a

PLB generates, be more likely to radiate out or be contained by the

structure?  I assume the PLB to be a line of sight signal.



Thanks Bill S

7a wiring 



--

craig(at)craigandjean.com
Guest

Posted: Mon May 29, 2006 12:19 pm Post subject: elt antenna

Since ELTs are required (and not a bad investment either) I see PLBs as an

addition, not an alternative. And my expected mode of use would be after

extracting myself (if possible) from the plane. Certainly as a general plan

those of us flying planes with bubble canopies should plan ahead for ways to

get ourselves out of an inverted plane on the ground. Or have a tool at hand

that can at least cut or break a hand-sized (and PLB-sized?) opening in the

canopy.



www.ch601.org/stories.htm



-- Craig

rv8ch

Joined: 10 Jan 2006
Posts: 250
Location: Switzerland

Posted: Mon May 29, 2006 1:57 pm Post subject: elt antenna

 	  Quote: 	
		   Mickey, I think the PLBs are a better option as well but have not seen any

 data on them in actual use.  Do you have any info that would suggest that a

 PLB signal is more likely to be received than a ELT if the PLB is inside an

 upside down metal aircraft ??  (typical Vans) Would the burst signal that a

 PLB generates, be more likely to radiate out or be contained by the

 structure?  I assume the PLB to be a line of sight signal.


	


Hi Bill,



No, I don't have any data on how effective the PLB will

be in the real world.  Hopefully some of the gurus can

chime in and give us an idea if they think it will be

better.



As I understand the PLB, they talk to one or more

satellites, so that would need to be line of sight.



Their frequency is higher, which should allow a

shorter antenna.  Hopefully they will get small

and cheap enough that we could afford to put in a

few of them in the aircraft, so no matter what part

survives, there is an PLB/ELT in there.



-- 

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

do not archive

_________________
Mickey Coggins
http://www.rv8.ch/

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