The Offshore Voyaging Reference Site

Review of Ocean Signal PLB3 Against MOB1

Ocean Signal1 have released the PLB3 Personal Locator Beacon that has both AIS and 406 MHz capability, as well a lot of other new features.

Let’s compare it to the Ocean Signal MOB1 that Phyllis and I have used since it came out and that I have written about extensively over the years (see Further Reading).

Feature / Specification MOB1 PLB3
AIS Alerting Yes Yes
406 MHz Alerting (satellite, same system as EPIRBs and COBs) No Yes
Return Link Service (confirms to the user that the distress signal has been received by the ground station; does not mean that a SAR mission has been launched) No Yes
121.5 MHz (older aviation distress frequency sometimes used by SAR assets to home in on an EPIRB) No Yes
VHF DSC alert (in countries where this is allowed) Yes No
Clunky, but usable, programming Yes No
Program and Monitoring with phone using Near-Field Communication No Yes
Visible Light Yes Yes
Strobe Yes Yes (IR)
Operational Life (hours) 24+ 24+
Height (mm) 134 200
Height (in) 5.27 7.9
Weight (grams) 92 160
Weight (lbs) .2 .42
Requires Registration No Yes
Street Price (US$) ~$335 ~$600
I have used bold type for the differences that I think are particularly important.

Ok, the new beacon has way more features and even works with our phones—queue gasps of delight—so it must be better.

Let’s all replace our MOB1s with PLB3s, and anyone who buys an MOB1 going forward is an idiot, right?

Nope, that’s the typical irrational decision making of us guys (women seem to have more sense) in which we automatically assume anything new and shiny with more features has got to be better, particularly if it has a companion phone app.

Let’s dig deeper: