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Old 20-05-2015, 03:45   #151
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Re: Are EPIRBs dead?

FWIW, a 406 beacon doesn't transmit 406 MHz per se rather there are a range of channels that the manfacturer can use when designing their beacons.As they are all near 406 MHz, they are collectively known just as 406.

Therefore receivers have to either boadbanded or fast scanning or have multiple frontends.
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Old 20-05-2015, 04:41   #152
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Re: Are EPIRBs dead?

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Originally Posted by socaldmax View Post
………...
121.5 MHz isn't too hard to DF, but 406 MHz will give you tighter bearing accuracy, and the much greater signal strength really helps with initial acquisition. Even if both signals were equal strength, the 406 MHz signal is inherently the superior signal to DF, just based on it's frequency.
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I…………...
The only thing I was arguing against was the impression -- and maybe you didn't intend it -- that 121.5 mhz homing is obsolete. It's not obsolete; it's primary, and it's built into all modern EPIRB and PLB sets. ……...

I am guessing -- and it would be useful to hear from a USCG SAR pilot -- that this would be really needed when rescuing someone who was dumb enough to buy a 406 mhz EPIRB without GPS. There the longer range would be helpful since you won't get an exact position from the satellites.
My emphasis!

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Originally Posted by nigel1 View Post
………..
What we need is a USCG pilot to step in and either confirm or deny.
Gentlemen, I can't give you a USCG SAR pilot but I can give an Aussie SAR pilot. I trust that you will accept his word and experience to be as good as a USCG one.

When I asked him today if he used 121.5 or 406 as a primary homing aid, his reply was unequivocal, 121.5 only. When pressed about 406, he said (verbatim) "406 is bludi useless".

In essence his experience is that as the 406 suffers two major drawbacks, the bearing updates (every 50 seconds) are too infrequent to be useful when one is moving about 1.5 to 2 miles between updates and as there is no meaningful audio in the transmission, one has to eyeball the homer display to extract any information.

121.5 on the other hand gives continious real time and dynamic bearing data and the audio can also be used in lieu of looking at the homer display. In fact, he tends to use the audio thus keeping his eyeballs outside looking for the target and just has the occasional scan of the display for confirmation of what his ears are telling him.

As for the extended range of the 406, he felt this was of little importance. While it is true there is better range of 406, it really wasn't used in real life. Invariably they have the coordinates of the search area and fly direct to that. The 406 bearing is thus always on the nose on departure and by the time they close the area, they are in range of the 121.5 anyway.

As for night searches with NVIS (NVG), he has sighted airborne strobes at 80 miles and surface strobes are only limited by the curvature of the earth (LOS) and of course, moisture in the air (clouds).

Surely this should settle the 121.5 vs 406 homing debate aspect of this thread!
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Old 20-05-2015, 05:10   #153
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Re: Are EPIRBs dead?

This explanation makes perfect sense. The 121.5 beacon is a continuos tone. So the ears give instant feedback.

I doubt the satellite devices will ever have this capability. But there are a lot of retired 121.5 homing beacons in closets and back rooms. If you can find one that works it might be something for the satellite only crowd to consider adding to their kit for not much $.

Some time back we had a long haul pilot here that said flight crews often keep a radio watch on 121.5 when over open water just in case. So if you are in trouble it can't hurt to have the 121.5 capability on board in addition to satellite comms. But the EPIRB is the most important device to have when the chips are down.
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Old 20-05-2015, 06:37   #154
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Re: Are EPIRBs dead?

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Originally Posted by Wotname View Post
My emphasis!





As for night searches with NVIS (NVG), he has sighted airborne strobes at 80 miles and surface strobes are only limited by the curvature of the earth (LOS) and of course, moisture in the air (clouds).

!
I've done night time interdiction missions with the U.S. Coast Guard in the Bahamas on their HH60's (a helo) and one of the things that really impressed me was how far we could see strobes at night through the NVGs. The first thing I did after coming back from that mission, was to buy strobes to attach to the life vests on my boat.

We closed in on one boat one night at a remote anchorage in the Acklins with a masthead strobe that I know I could see from at least 20 miles away through the NVG's. When we radioed him, he found he had just turned it on by accident instead of his normal anchor light.

And, really any light shows up well at night through the NVG's from the air, especially in remote areas, but the strobes were impossible to miss.
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Old 20-05-2015, 07:29   #155
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Re: Are EPIRBs dead?

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Originally Posted by brianb00 View Post
the USCG is committed to a 95% response rate within 4 minutes of a ping from an EPIRB/PLB. If you push the little red button you can bet the USCG will react immediately with the highest priority. Did you know that in the San Francisco area they have rotors spinning on helo's within 7 min of a received EPIRB signal ?

Does the Coast Guard in San Francisco really dispatch a helicopter immediately upon receipt of every EPIRB signal within range? Is there no screening process for false alarms or consideration of sending a less expensive SAR asset?
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Old 20-05-2015, 08:30   #156
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Re: Are EPIRBs dead?

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Originally Posted by CarlF View Post
I figured the title would get some attention. I actually do have an EPIRB (and a PLB) but they are now the backup. But after a year with my Delorme Inreach it is my primary offshore communications system (I believe the Yellowbrick is very similiar).

When the EPIRB's batteries reach EOL I may just get a 2nd InReach instead of replacing the EPIRB. I won't go offshore without an Inreach -- even on someone else's boat.

As a distress communication it beats the EPIRB hands down as it provides two way communication with a staffed 24/7 rescue center or anyone with an email address - like your family. The EPIRB just blinks. Waterproof and 4 day battery in a package the size of most PLBs can be clipped to the life jacket on the way to the liferaft. And it worries me that my EPIRB can't really be tested until I'm in a liferaft. I know the InReach works.

As a global offshore communicator, mine is always turned on (it works fine sitting on the chart table sending through the fiberglass overhead). If someone sends me a message, it beeps until I read it. An end to checking for traffic. And an end to coordinating once a day Ham or SSB schedules. While each email can only be 160 characters long, anyone under age 30 will tell you that's plenty.

In my experience it is far more reliable than Ham, SSB, or Sat phone. So far, the InReach has always found an Iridium satellite and sent the message within two minutes - regardless of weather, time of day, traffic, etc - No propagation worries. No dropped calls. No "try again later".

The only thing I miss are GRIB files. But it's easy to have a shore side friend send you abbreviated weather as needed in 160 character pieces - and Ocens will do it for $8 a month.

The Delorme costs $300 and the service starts at $15 a month and $0.10 a message with no contract. As I mentioned, I believe the Yellowbrick is very similiar.

Carl
One is not intended to replace the other.

An EPIRB transmission has as close to a guaranteed SLA for message delivery that you'll find. They also auto activate when submerged.

With any of the satellite based systems they are not much different to say email or sms. Neither if which have an SLA guaranteed delivery. If the service gets congested you have no comms.

Ham, ssb and epirb dont require an ongoing subscription be maintained.

I think having redundancy is the most important factor.

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Old 20-05-2015, 09:26   #157
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Re: Are EPIRBs dead?

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Originally Posted by leftbrainstuff View Post
One is not intended to replace the other.

An EPIRB transmission has as close to a guaranteed SLA for message delivery that you'll find. They also auto activate when submerged.

With any of the satellite based systems they are not much different to say email or sms. Neither if which have an SLA guaranteed delivery. If the service gets congested you have no comms.

Ham, ssb and epirb dont require an ongoing subscription be maintained.

I think having redundancy is the most important factor.
The EPIRB system as part of GMDSS is specifically designed to get a distress message through no matter what. It's a primary design parameter which is everywhere in the whole system. It doesn't mean it's infallible, but it does mean that the risks of the message not getting through are far less than with a consumer messaging system which is designed according to other values.

Besides that, GMDSS itself is a whole system which was also designed to avoid screwups and save lives. You really want that on your side, when the stuff hits the fan and you need rescuing. So of course, start off with the real, certified, GMDSS equipment and procedures, and don't confuse them with consumer messaging systems. A lot of people have been saying exactly this and we are maybe doing some dead horse beating here, but it's important.


I would quibble just a little bit with the statement that "having redundancy is the most important factor." Redundancy CAN be very valuable, but it is by no means the most important factor. If you go to sea with a rusty old VHF, a child's walkie talkie, a cell phone, and a sat phone with expired subscription, for example -- you've got lots of redundancy, but it's not doing anything for you. Much better a single in-date EPIRB than all that redundancy, if you had to choose. This is actually close to the Rebel Heart situation -- he had a sat phone, he had an SSB, hey I've got redundant comms, check that box and forget about it, I'm all set.

And he wasn't at all "all set" -- the SSB didn't work and/or he didn't know how to use it, and his sat phone subscription was expired. Which led to the loss of his uninsured boat. The idea that "redundancy is the most important factor" was in all probability exactly what lost Eric his boat.


So you should pick really robust true GMDSS systems as your primary method of emergency signalling, then by all means go with something else (Iridium phone, InReach, etc.) as a supplement and backup.

Yes, we're beating a dead horse, for which I apologize.
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Old 20-05-2015, 10:06   #158
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Re: Are EPIRBs dead?

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Originally Posted by Wotname View Post
FWIW, a 406 beacon doesn't transmit 406 MHz per se rather there are a range of channels that the manfacturer can use when designing their beacons.As they are all near 406 MHz, they are collectively known just as 406.

Therefore receivers have to either boadbanded or fast scanning or have multiple frontends.
Making a broadband receiver is actually easier than a narrowband receiver.
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Old 20-05-2015, 10:10   #159
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Re: Are EPIRBs dead?

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The EPIRB system as part of GMDSS is specifically designed to get a distress message through no matter what. It's a primary design parameter which is everywhere in the whole system. It doesn't mean it's infallible, but it does mean that the risks of the message not getting through are far less than with a consumer messaging system which is designed according to other values.

Besides that, GMDSS itself is a whole system which was also designed to avoid screwups and save lives. You really want that on your side, when the stuff hits the fan and you need rescuing. So of course, start off with the real, certified, GMDSS equipment and procedures, and don't confuse them with consumer messaging systems. A lot of people have been saying exactly this and we are maybe doing some dead horse beating here, but it's important.


I would quibble just a little bit with the statement that "having redundancy is the most important factor." Redundancy CAN be very valuable, but it is by no means the most important factor. If you go to sea with a rusty old VHF, a child's walkie talkie, a cell phone, and a sat phone with expired subscription, for example -- you've got lots of redundancy, but it's not doing anything for you. Much better a single in-date EPIRB than all that redundancy, if you had to choose. This is actually close to the Rebel Heart situation -- he had a sat phone, he had an SSB, hey I've got redundant comms, check that box and forget about it, I'm all set.

And he wasn't at all "all set" -- the SSB didn't work and/or he didn't know how to use it, and his sat phone subscription was expired. Which led to the loss of his uninsured boat. The idea that "redundancy is the most important factor" was in all probability exactly what lost Eric his boat.


So you should pick really robust true GMDSS systems as your primary method of emergency signalling, then by all means go with something else (Iridium phone, InReach, etc.) as a supplement and backup.

Yes, we're beating a dead horse, for which I apologize.
No apology warranted. A great sum-up to an informative thread about the usefulness of all these devices, especially for the non-techy laymen out there. I suspect there are many like Eric with SSB's they are not sure now to work, and satphones that haven't been properly tested. Then again, a two-way messenger like the DeLorme could have gone a long way in re-establishing comms. when they were dealing with a sick infant. But at the same time, I think I recall it was their EPIRB which ultimately saved the day.(??)
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Old 20-05-2015, 14:19   #160
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Re: Are EPIRBs dead?

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. . .Then again, a two-way messenger like the DeLorme could have gone a long way in re-establishing comms. when they were dealing with a sick infant. But at the same time, I think I recall it was their EPIRB which ultimately saved the day.(??)
Absolutely. I think that two-ways comms are invaluable and I especially like these satellite text devices. As we know from using regular mobile phones, text messages get through more reliably and consistently than voice. As we know from SMS messages, probably 95% of anything you want to say to someone can be put in 164 or whatever the number of characters there are in an SMS, or at worst two or three of them. I have never wanted a sat phone (actually I have a fixed mounted one which came with my boat, but have never activated it), but I definitely want a Yellow Brick or Delorme.

My Plan “A” for two way comms in the middle of the ocean would be HF radio and email by Pactor. But satellite messaging will definitely be Plan “B”. You can’t take the SSB in the life raft with you.
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Old 20-05-2015, 15:39   #161
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Re: Are EPIRBs dead?

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One is not intended to replace the other.

An EPIRB transmission has as close to a guaranteed SLA for message delivery that you'll find. They also auto activate when submerged.

p
I'm rather concerned at the number of people that think epirbs auto activate when submerged. They don't! Not unless you have them in an automatic deployment case. Those systems are roughly twice the cost as a plain Epirb.
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Old 20-05-2015, 16:04   #162
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Re: Are EPIRBs dead?

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I'm rather concerned at the number of people that think epirbs auto activate when submerged. They don't! Not unless you have them in an automatic deployment case. Those systems are roughly twice the cost as a plain Epirb.
I'm glad you brought this up as I own one that is currently out for service/batt. replacement, and I have some questions about its auto-deployment which I intend to ask the service center. Specifically, there's the module (Alka-Seltzer tablet) that I believe frees it from its case ($120 replacement fee!), and then there's its ability to automatically switch itself on. From looking at it, it seems like these are two separate functions but I'm not entirely sure. Although it is pressure rather than mere water-activated when submerged, installing it in a suitable location away from too much splash, but also allowing it to float to the surface, remains somewhat challenging (at least on my boat). The place I have chosen thus far was probably a poor one, but perhaps the aft rail/pushpit may be more suitable. I'd be curious to know what others with these types of units do.
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Old 20-05-2015, 16:38   #163
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Re: Are EPIRBs dead?

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I'm rather concerned at the number of people that think epirbs auto activate when submerged. They don't! Not unless you have them in an automatic deployment case. Those systems are roughly twice the cost as a plain Epirb.
Well, don't bang your head too hard, because in fact some type II models ("manual" Not hydrostatic) do salt water activate. They have two exposed pan head screws on the base or side, and if there is a salt water connection across those screws they activate. This specifically happened in the low speed chase incident - the Epirb got wet in the knockdown and fired off without being manually activated. Both ACR and McMurdo have type II models which do this. They both also sell brackets with built in magnets which hold reed switches open so they will not fire when wet, unless manually released from the housing.

This is copied out of a McMurdo type 2 users manual : "The two studs on the sides of the EPIRB are sea switch contacts. Submerge these in water to activate the EPIRB automatically." http://www.mcmurdomarine.com/images/...Murdo%20V2.pdf
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Old 20-05-2015, 19:57   #164
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Re: Are EPIRBs dead?

Carl-
"Does the Coast Guard in San Francisco really dispatch a helicopter immediately upon receipt of every EPIRB signal within range? Is there no screening process"
AFAIK NO ONE responds to an EPIRB without screening. That's why you register your beacon with the NOAA (not the USCG) or other national authority. The message is picked up by the COSPAS-SARSAT system, and depending on the beacon information, it is sent to the appropriate authority, who will then call down the list of emergency contact phone numbers you have given them, along with other posted information. (For instance, I can open my registration form online and add the note "FROM MAY 20 to JUNE 20, 2015, I WILL BE AT SEA AND ANY EMERGENCY TRANSMISSION CONSIDERED IMMEDIATELY VALID, PLEASE DO NOT WASTE TIME ON PHONE CALLS."
Procedure may still be to make the calls--but you can bet the USCG will be alerted without delay. It is only after NOAA or a similar national agency has passed on the alert message, that SAR assets are launched. Or so I'm told.
The 406 beacons are also very low power, and directional (aimed "up") making in unlikely that a ground station is going to get much out of monitoring them. False beacons of all kinds have always plagued rescue systems. In fact, an early Panasonic(?) large screen plasma TV triggered the system once, maybe 10-15 years ago, and there was hell to pay for that. The man watching his TV when all the uniforms showed up was not amused either.



Exile-
"but rather the guy sitting in front of it turning the dials & pushing the buttons! "
From a friend who is a pilot and aviation consultant:
"Only push the shiny buttons!"
Meaning, that if you have to fly a strange aircraft, you only push the buttons that obviously are shiny from heavy and regular use. The stuff that looks like it isn't usually touched? You just don't touch. That applies & works pretty well to everything that has more than one button on it.(G)


Coupla thousand years ago, I knew how to run my parent's Super8 (or was it just 8?) projector. Then I saw the Bell & Howell, the original company, AV projectors in high school. They all had a red enameled line running on the side of the projector, tracing out the film path, so there was no way any idiot could thread the film in the wrong sequence.
From that I learned "equipment" could be made damn near idiot-proof, IF the guys who built it weren't idiots. I call that red line "exquisite! damn fine engineering!" and while something like an SSB might need a "quick start book" to do the same thing...it certainly can be done. The "Dummies" books aren't the only way to go.
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Old 20-05-2015, 20:15   #165
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Re: Are EPIRBs dead?

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Does the Coast Guard in San Francisco really dispatch a helicopter immediately upon receipt of every EPIRB signal within range? Is there no screening process for false alarms or consideration of sending a less expensive SAR asset?
Because of the 95 % false rate, the RCC will take time (upto 40 minutes typically) to try to confirm that it is an actual emergency and not a false alert, before launching assets. And the actual USCG response time standards are :

"SAR Readiness: Each Coast Guard unit with a SAR readiness responsibility shall have a suitable SAR resource ready to proceed within 30 minutes of notification of a distress.

SAR Mission Response: No greater than a two-hour total response time for any one response unit within a Sector or unit’s AOR to arrive at any location within the AOR. This time is calculated from time of notification of the Coast Guard until the time of arrival on scene, including 30 minutes of preparation time (i.e. a total of 90 minutes from underway to on-scene). "

And on a prior topic of debate, not only can USCG assets home on 406 signals (as you all eventually agreed), but they can also in fact de-code and read the signals directly on board - so if it's a g-Epirb they are directly getting the real time location bursts and updating their waypoint.
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