With all the talk going on about climbers and GPS, I thought this might be of interest. It was posted on CC by Iain, a member of the SAR team.
Hope some find it helpful:
Questions continue to be asked about the Mount Hood Locator Unit (MLU) after every search like this last one. Some of the media somehow still confuse them with PLBs and cellphones, and I have been asked to outline the program, so this is just to reiterate what the MLU does.
Availability-
REI, OMC, and the Mountain Shop all "rent" MLU transmitters to climbers. They are also available 24 hrs a day at the Mount Hood Inn at Government Camp. The rental shops test each transmitter in front of the climber renting it. Records are kept on battery life. A $5 rental fee covers the expense of this.
History-
The MLU program began back in 1986 in the wake of one of Mt Hood's largest tragedies, where a large group from the Oregon Episcopal School became trapped near White River Canyon, resulting in 9 deaths. It took three days to find the unmarked, buried snow cave, and by then it was too late for 7 of the kids and 2 adults.
The Mountain Signal Committee built and tested the technology, then went through the Oregon legislature to get enabling legislation to use the system. Currently the USFS and Clackamas County Sheriff control the system.
The MLU Transmitter-
MLUs are small VHF transmitters attached to a sash. When the "ripcord" is pulled and the MLU activated, it sends out a tone at 168.54 mHz. These transmitters are not monitored full-time. Once a rescue is initiated, PMR will do an initial sweep of the mountain for an MLU signal. There is a check box to say you are carrying one on the sign-in sheets at Timberline, but frequently PMR will do a scan just in case you forgot to check the box, or if you didn't register.
The MLU system is essentially a wildlife tracking system. During testing, MLU transmitters have been picked up 20 miles away. Transmitters deep in crevasses or under many feet of snow have been easily detected. However, line-of-sight rules apply. PMR can't find a signal on the opposite side of the mountain, behind a ridge, or deep in a canyon. The signal will also "bounce" off wet rock walls, making it confusing for the searcher at times.
Should you use one?
There is no doubt the MLU takes the "search" out of search and rescue. It has been used successfully in several winter operations on Mt. Hood. The technology, now 20 years old, still works well. It is not perfect, but it remains a powerful tool for PMR.
Carrying an MLU does not guarantee a rescue. Sometimes accessing your location is impossible due to weather, avalanche, rockfall, etc. However, it does allow all energy to be focused on accessing your location and getting you out of there, rather than trying to find you first, which as you have seen can take days.
Many climbers feel it is inappropriate to take technology along that replaces self-sufficiency. Many climbers do not bring cellphones with them for this reason. This is an understandable personal choice climbers make. Climbing is often viewed as an opportunity to escape society. This message is simply to let people know the MLU still does its job well, and if you wish to rent one, it is available as a tool for you to use, and will be used to find you if you get in trouble on Mt. Hood.