On Thursday, June 11, 2015 at 10:56:44 AM UTC-7, danlj wrote:
Let's cut through the fog and quit kvetching about irrelevancies such as CAP arrogance.
406-mHz ELT or PLB: location accuracy 100 meters
ELT cost: $650+
PLB cost: $250+
(If you can afford to fly, you can afford one)
121.5 mHz ELT: location accuracy 12000 meters
ELT cost: your life

If you don't put a GPS-equipped 406 mHz ELT in your aircraft or PLB on your straps, don't complain about the CAP, your spouse, or God when you're lying broken and cold and in pain in the wreckage. Blame yourself.

References:
http://www.sarsat.noaa.gov/406vs121.pdf
http://en.wikipedia.org/wiki/Distress_radiobeacon
http://www.sarsat.noaa.gov/emerbcns.html

As other are pointing out the "121.5 mHz ELT: location accuracy 12000 meters" comment has no meaning. This is an old accuracy number from SARSAT/COSPAS Doppler ranging. But since SARSAT/COSPAS no longer monitors 121.5 MHz beacons at all the accuracy has no meaning. And the fact that it is not SARSAT/COSPAS monitored it the main reason you don't want to rely on just a 121.5MHz ELT. 121.5 is still monitored by airliners, etc. and can be homed to high precision (but that needs time) by just about every SAR organization. All 406Mhz ELTs and PLBs also include a 121.5Mhz beacon to make detection of and homing by SAR teams easier... which is important to remember, if you think a glider is down and they have any type of ELT or PLB you want to be checking 121.5 Mhz. PLBs (but not ELTs) in the USA also have more code "P" (dit dah dah dit) added to that beacon (that was an FCC idea to try to filter the expected onslaught of idiot consumers activating PLBs, but which did not happen...maybe because idiot (and smart) consumers brought SPOT and InReach devices instead :-)).

The issues with ELTs are they are hard to properly mount in a glider, hard to actually test (you can't drop the glider on the ground from height, break the glider in pieces, tip it on it's side and then see if the ELT actually worked and provided a good RF signal), and just do not reliably activate at all even in GA aircraft, let alone gliders. I think the ELT or PLB is best seen as an important/very useful back-up for InReach or Spot. And I'd do everything I could using modern technology to reduce any reliance on the weekend warriors in CAP... which today would start with InReach, high rate tracking and a savvy/well informed ground crew/club/FBO etc. with an agreed plan in case of concern/distress/loss.