A Mountain Locator Unit or MLU was a
radio transmitter
In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the ...
for use by
mountain climbers as an emergency
locator beacon when the wearer needs rescue.
The MLUs were simple radio beacons, and thus required
search and rescuers to use traditional
radio direction finding (RDF or DF) equipment to obtain a
bearing, but not a precise location, to the beacon.
Unique to
Mount Hood,
these devices could be rented for $5 at
Portland-area outdoor shops and the Inn, open 24 hours a day. The units were available from the late 1980s until 2017, but advances in technology now provide superior locating information by devices such as a PLB, InReach or Spot.
Groups scaling Mount Hood are recommended to carry an emergency signaling device and all climbers must register before climbing and sign out upon return.
The MLU was designed after a school group with two adults and seven children perished on Mount Hood in 1986. (See
Mount Hood climbing accidents.) The bodies of some of the group were found in a snow cave a day after the searchers had passed within fifteen feet of their shelter without noticing them.
According to Steve Rollins of
Portland Mountain Rescue Portland Mountain Rescue is a search and rescue organization based in Portland, Oregon, United States. It specializes in high angle mountain rescue and mountain rescue in northwest Oregon and southwest Washington, as well as providing educational ...
, the units could be worn on a sash across the chest and were relatively light.
Renting MLU's was less expensive than either purchasing or renting a
personal locator beacon, which typically cost several hundred dollars to buy, or rent from various sources for around $50 per week.
The Mount Hood MLU system was controlled and maintained by the U.S. Forest Service and Clackamas County Sheriff. Transmitters broadcast at 168.54
MHz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is sā1, meaning that one he ...
and provided good signals even when buried in snow. They could be received at up to , though the signal travels in line of sight, so they could not be received from behind a ridge or deep in a canyon. The technology is very similar to wildlife tracking systems.
A Mountain Locator Unit only transmitted a signal and did not initiate a rescue (when you activated an MLU beacon, there was no one monitoring for signals, the device only assisted rescuers in locating lost climbers once a rescue has been requested by other means and rescuers know to listen and search for the beacon's signal. They were also not designed to be used for avalanche safety (avalanche beacons are entirely different than what MLU's were designed for.)
The use of MLU Beacon technology was overtaken by availability of Personal Locator Beacons (PLBs) and other technologies such as "SPOT Satellite GPS Messengers". These newer technologies not only allow rescuers to determine your location, but they also have the ability to initiate a rescue by alerting authorities that you are in need of help.
In fact, most modern cell phones have built in GPS receivers. If a climber calls 911, the cell phone may automatically provide emergency services with the climber's GPS coordinates. Cell phones also allow the lost or injured climber to provide important information to rescuers, such as the nature of any injuries; however, cell phone coverage on Mount Hood can be spotty and they are therefore not necessarily a replacement for other technologies such as PLBs which leverage satellites overhead for communication.
Oregon State Representative
John Lim (R) introduce
House Bill 2509 which would require climbers to use an electronic signaling device when climbing above 10,000 feet between November and March. The
Oregon House of Representatives passed an amended version
[A-Engrossed House Bill 2509](_blank)
of the bill 33 to 22 on March 28, 2007 after a lengthy floor debate
and passed it onto the
Oregon State Senate where it died in committee.
[2007 Oregon House Measure History](_blank)
The bill was widely opposed by mountain rescue organizations for fear that it would cause inexperienced climbers to rely on rescuers to save them rather than learning to become self-reliant.
See also
*
Mountain rescue
Mountain rescue refers to search and rescue activities that occur in a mountainous environment, although the term is sometimes also used to apply to search and rescue in other wilderness environments. This tends to include mountains with tech ...
References
External links
Wilderness Protocol
Emergency communication
Hiking equipment
Mountaineering equipment
Rescue equipment