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Old 10-05-2012, 04:48   #31
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Re: EPIRB

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Originally Posted by Wotname View Post
Which website was this from; it differs from significant other EPRIB sites. I don't have time tonight to link other sits but I can later!

I think you find that most if not all marine applications will have a clear view of the sky for the GPS component when activated!
SARSAT site I think..plus 20+ years as a USCG helo pilot/SAR watchstander...you can think whatever you like...me I'm going with practical in the field results...not what "some website" may say.

From another website..

The Cospas-Sarsat System design constellation is four satellites which provide a typical waiting time of less than one hour at mid-latitudes.

I will admit that certain areas of the globe without the LUTs will have longer aquisition times/degraded accuracy...but many of the highly travelled areas are designed to work just fine without GPS.
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Old 10-05-2012, 05:41   #32
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Re: EPIRB

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Originally Posted by psneeld View Post
SARSAT site I think..plus 20+ years as a USCG helo pilot/SAR watchstander...you can think whatever you like...me I'm going with practical in the field results...not what "some website" may say.

From another website..

The Cospas-Sarsat System design constellation is four satellites which provide a typical waiting time of less than one hour at mid-latitudes.

I will admit that certain areas of the globe without the LUTs will have longer aquisition times/degraded accuracy...but many of the highly travelled areas are designed to work just fine without GPS.
Thanks for the update, I don't believe or disbelieve anything posted here but I do use the information to form a full(er)picture.

I do push the point that given the current pricing, a GPS embedded EPRIB really makes sense and I note that you agree I don't recall ever suggesting that a non GPS beacon is unsuitable. If you read that into my posts, then that is possibly my poor writing skills or perhaps a american/ english translation issue.

I also note that I was incorrect with the 20 Km radius claim, this was for the now discussed 121.5 / 243 MHz units - my bad, must be getting old. As for position location time, this from AMSA :

Orbiting satellites will calculate the position if there is no GPS capability. These orbiting satellites take 90 minutes on average to receive the signal but it may take up to 5 hours depending on the conditions.

More information is needed to determine the real location. This usually means at least two satellite passes &/or independent intelligence is required to determine a location and this takes more time. Non GPS has an accuracy locator of 5km


Further reading on Wikipedia gave an interesting point which I have missed in the past:

EPIRB beacons with built-in GPS are usually called GPIRBs, for GPS Position-Indicating Radio Beacon or Global Position-Indicating Radio Beacon.
However, rescue cannot begin until a doppler track is available. The COSPAS-SARSAT specifications say [27] that a beacon location is not considered "resolved" unless at least two doppler tracks match or a doppler track confirms an encoded (GPS) track. One or more GPS tracks are not sufficient.


This has been referenced against COSPAS-SARSAT document A.001, 2005.

I hadn't come across this aspect before and I must check with some mates at the Australian RCC to get their view.

If it really makes any difference, I am always learning something new about beacons although I have been installing, testing and repairing them for 20+ years.
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Old 10-05-2012, 12:14   #33
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Re: EPIRB

Read wikipedia all you want...that's not how it really works in the US. Once a geosar sat gets the beacon ID ..the process starts. NOAA calls the approriate USCG area and they make the NOK calls...This is the same GPIRB or not. After some basic answers are answered...the rescue starts...ready crews are put on alet and if the NOK call produces the usual answer...yes...he/she's sailing from a to b, fishing at the"xxx", etc...etc...by now the ready crews have briefed and are ready to launch...again about the same for EPIRB/GPIRB....maybe about an hour after you set off the beacon...then based on info, a launch is authorized. By now...in many cases the beacon is "resolved" and everyone lives happily ever after.

It is VERY rare not to "find" an EPIRB in a little hour more than the flying time to get there...so all in all...there's not much of a delay because you don't have a GPIRB.

Again I will say...that's in the heavily travelled mid-latitudes and prominent routes in the Atlantic/Pacific....outside of those WAY better to have a GPIRB and be prepared to survive at least several days till rescue arrives.
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Old 10-05-2012, 13:25   #34
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Re: EPIRB

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What is your boat worth?

What is your life worth?

What is worth of your crew's lives?

What does it cost to change a battery?
Did not read the whole thread but.......my thoughts.
Change the bat........
Keep reg currant...........
Think about the men that are putting there asses on the line before you push the switch......If it is that bad do you want them there?
Can you live with a helo crew dead at sea and you live?
My thoughts
Mark
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Old 10-05-2012, 17:28   #35
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Re: EPIRB

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Did not read the whole thread but.......my thoughts.
Change the bat........
Keep reg currant...........
Think about the men that are putting there asses on the line before you push the switch......If it is that bad do you want them there?
Can you live with a helo crew dead at sea and you live?
My thoughts
Mark
if the helo crew dies....it wasn't your fault for punching the EPIRB.....

something else went wrong...but asking for assistance any time, any place is OK....they don't have to respond or push on. mechanical, error, something else can happen...but NEVER not request help if you need it.
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