Basejumper.com - archive

 

Nah.. If im alive I can scream to get attention, if I'm dead; who cares...

Carried one( ACR) around with me on several different occassions. If you plan on being in an area where cell coverage is questionable and you might need recovery from, they are worth their weight in gold.


Only if you are unconscious or can't turn it on. PLBs can only be activated manually and operate exclusively on 406 MHz. Some newer PLBs also allow GPS coordinates to be integrated into the distress signal.This GPS-encoded position dramatically improves the location accuracy. You can find more information HERE

 

You are thinking GPS RECEIVER. The PLB TRANSMITTER, sends out a signal on 406mHz that is picked up anywhere in the world, in any environment by the appropriate platforms be it a satellite,LEO or aerial . The RCC (Rescue Coordination Center) will pick up the beacon distress signal and they will tri-angleate your position. They have some really cool programs to figure for ellipse deviation and all the other gee-whiz stuff that goes into pinpointing the location of the transmition and they can narrow down the location to within a few hundred meters to a click depending on the terrain. The most I have seen it was a click but that was an airplane crash on a snow covered mountain side at nearly 16,000 feet with wreckage spread out. The times I have used the personal beacon during official military training, the signal was picked up immediately and the response was quick.As soon as you turn that thing on several locations around the world will know about it and will begin investigating the signal and making phone calls to determine if it is a real situation and to take the needed steps to effect a rescue. It may be awhile before someone shows up at your location but make no mistake, as soon as you turn it on bells and whistles are going off at the RCC and people are moving.

The commercially available PLBs are really quite simple, Buy one, register it with the authorities(so they know who they are looking for and this also authenticates that the signal is valid since the device is registered.This is very important), Turn it on if and when you need it, wait for rescue. You don't have to worry about satellites.

 

The GPS function is strictly internal and cannot be used like a typical GPS for navigation. It has no screen or buttons other than to turn the GPS function on so that your coordinates are transmitted with the distress signal. On the ACR unit with GPS, all that is visable is a little LED light letting you know that the GPS is active. If your PLB's GPS receiver can "see" enough satellites and has a fix locked in, those coordinates will be transmitted along with the distress signal on the 406MhZ frequency.

You need a Minimum of 4 satellites for a position solution with GPS (This is 3 coordinates (i.e. x,y,z) and time (you need a time measurement to solve for the satellite clock error and to solve for time- you know 4 unknowns, so you need 4 equations). The fourth satellite provides this. Depending on the receiver and accuracy required you may need more.


While It may be true that you only need one satellite to use a satellite phone, you will (as far as I know) not be able to get a position from it.

As far this application getting a position at the bottom of a canyon, right next to a cliff, for example, is still possible. Remember that this receiver would have to be out in the open, and not obscured. From my thinking, the Beacon sounds like it would be more dependable in a situation like this.

Keep in mind here that we are talking about PLBs. The satellites used for GPS and for Satellite phones are completely seperate and different from one another and the later 2 have absolutely nothing to do with how a PLB functions. When turned on, a PLB becomes an active TRANSMITTER for as long as it is turned on. The apparatus set up to facilitate the process from A to Z(your being rescued) is quite extensive. As long as you are not in a building or in a cave, the PLB signal will be received. The only place I belive they had some issues(along with other devices) was/is at portions of the planets Poles.

I hope the casing is very strong, and that the button is covered with something also very strong.

Edit to add: Also wondering about battery life?

it would be cool to have a base-friendly version where you activate it right before you jump, and if you dont deactivate it within, say, 8 minutes, it starts transmitting.

Great for those solo jumps when your out in the boonies

Just my opinion. Using a PLB would just put base in the eyes of the negative public. Just lay there and die like a man or jump with others and have a plan for self-rescue.