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I bought a PLB

Started by Stonewall, April 16, 2021, 03:20:58 PM

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Stonewall

I got a wild hair and purchased an ACR PLB-425 ResQLink View personal locator beacon (PLB).



I have become very curious about how the whole 406 MHz search and rescue response works so I was looking at DF equipment and then got into the process in which someone activates their beacon,  notification is made, teams/resources are activated, and ultimately, how is the person/target found.

Here is perfect diagram of how that process works:



Here's the interesting thing: it emits a 121.5 MHz signal.  My question is, at what strength?  Can that 121.5 signal be prosecuted by standard DF equipment such as the L'Per, Sniffer, or my favorite, the JetStream receiver?

In purchasing my PLB, it came with an official NOAA Registration Form, that I opted to complete online. You have to provide a lot of information (three separate serial type numbers) to authenticate that this is YOUR beacon and all three identifying number/letter sequences have to match. You provide as many phone numbers as you can, your address, and two emergency contacts. I opted to include my wife and my work's 24/7 operations center that, for at least the next two years, knows everything about me, to include my vaccine record, DNA, and whereabouts. You have to re-register (update) every two years.

In layman's terms, here's how  it works:
-   You're lost: turn on your PLB (it has pictures with how to do this)
-   Remain in the same place, do not move
-   SARSAT will pick up your signal and location (pinpointed to exact location +/- a few feet)
-   NOAA will contact the local (to your location) authorities  (could be LE/Fire/EMS or the fish and wildlife agency, or anyone)
-   They will move to your last known location as provided by NOAA
-   If you moved, doom on you, but you should be rescued
-   Go home, eat, rest, then go onto survivorclub.com and share your story
Serving since 1987.

Eclipse

Confused.

Who gets the ribbon?

"That Others May Zoom"

NovemberWhiskey

Quote from: Stonewall on April 16, 2021, 03:20:58 PMHere's the interesting thing: it emits a 121.5 MHz signal.  My question is, at what strength?  Can that 121.5 signal be prosecuted by standard DF equipment such as the L'Per, Sniffer, or my favorite, the JetStream receiver?

Typically 50-100mW. It's your standard 121.5 MHz AM "whoop-whoop" so absolutely, yes, you can localize it with standard DF equipment assuming you start off close enough.

BJD

Your PLB 121.5 output power is between 25mW and 79mw.  That is a weak signal that is hard to pick up unless close by.  Be sure to read the full owners manual (not just the quick start guide).  Operator errors can cause substantial problems with location accuracy.  Accuracy also depends on which of the SarSat systems picks up the signal.

Stonewall

Quote from: BJD on April 16, 2021, 06:31:48 PMYour PLB 121.5 output power is between 25mW and 79mw.  That is a weak signal that is hard to pick up unless close by.  Be sure to read the full owners manual (not just the quick start guide).  Operator errors can cause substantial problems with location accuracy.  Accuracy also depends on which of the SarSat systems picks up the signal.

I did all that before I ordered it.
Serving since 1987.

etodd

I got a Spot awhile back. Great reviews and over 7500 saves thus far. I'd bet with virtually zero CAP assistance.

Find Me Spot

Not only as a PLB, but will also send messages to people on your list to let them know you're ok. And will leave breadcrumbs so people can follow your progress online.  Nice system.
"Don't try to explain it, just bow your head
Breathe in, breathe out, move on ..."

NovemberWhiskey

SPOT is not a PLB. It is a satellite messenger with commercially operated emergency response centers which will escalate to SAR functions on your behalf.

etodd

Quote from: NovemberWhiskey on April 16, 2021, 10:11:05 PMSPOT is not a PLB. It is a satellite messenger with commercially operated emergency response centers which will escalate to SAR functions on your behalf.


True, which makes it even better. But all these types of devices have various uses which will suit people's needs. A good thing. Signals sent to satellites so centers can all the local folks quickly. Cuts response time considerably over the typical CAP time (Excepting the cell phone response team of course). New technologies replace the buggie whips. :)
"Don't try to explain it, just bow your head
Breathe in, breathe out, move on ..."

NovemberWhiskey

Quote from: etodd on April 17, 2021, 12:17:59 AMTrue, which makes it even better.
Well, it makes it different. Comparing satellite messengers like SPOT vs. PLBs, the following are noteworthy:

  • Messengers are multi-purpose devices that are useful for providing breadcrumbs trails and sending reassuring messages to friends/relatives when off-grid; whereas PLBs are single-purpose emergency usage devices
  • SPOT in particular does not have global coverage (the Garmin/DeLorme ones use Iridium which does), unlike a PLB
  • Messengers need a relatively good view of the sky to talk to their satellites due to lower-power operation, they're also useless if they can't get a GPS fix; PLBs are much higher power and can still provide a gross position to the satellites via Doppler location even if no GPS fix is available
  • PLBs usually have five-to-ten year primary cells, run continuously for a long period once activated and don't have subscription fees; your messenger may have rechargeable batteries you need to remember to keep charged and will have a monthly fee
  • PLBs tend to have other survival-relevant features like buoyancy, integrated strobe etc. which messengers do not
  • The Cospas/Sarsat system is governmentally-operated (e.g. notification will come into the AFRCC if you turn your PLB on in the U.S.) vs. a commercial service for the satellite messengers

This is definitely a case of "choose the right tool for the job".

Eclipse

Best practice:

"No bars, you've gone too far."

"That Others May Zoom"

Spaceman3750

Quote from: Eclipse on April 17, 2021, 05:17:42 PMBest practice:

"No bars, you've gone too far."
On your cell carrier, that was basically the case whenever I walked inside my home, office, or drove between two towns.

Eclipse

Quote from: Spaceman3750 on April 18, 2021, 02:46:35 PMthat was basically the case whenever I walked inside my home, office, or drove between two towns

Knowing where you live, this makes my point.

"That Others May Zoom"

PHall

I can get "no bars" in many locations in the Los Angeles Basin.

Eclipse

Quote from: PHall on April 18, 2021, 05:12:22 PMI can get "no bars" in many locations in the Los Angeles Basin.

Anyone who has been there knows it's not fit for man nor beast.  Best to steer clear.

"That Others May Zoom"