Edited by Rachel Duncan 4th Edition ISBN 0-907649-91-2 London ...

70 RGS-IBG Polar Expeditions Manual
penalties and should only be used in the case of real emergencies. Many countries now
require expeditions travelling in their remote areas to carry PLBs.
The satellite coverage of 121.5 MHz units will be stopped in 2009. Therefore, you
are recommended to only purchase a 406 MHz transmitter. The key advantages of the 406
MHz beacons is that they are more accurate and also transmit the unit’s unique reference
ID number. As they need to be registered to a government body after purchase (in the UK
the HM Coastguard’s EPIRB Registry), in the event of the beacon being used, a nominated
contact person is called to alert the contact that the beacon has been used. The most up to
date models now incorporate a GPS and can transmit the precise location.
For more information on how the system works, take a look at the COSPAS-SARSAT
website www.cospas-sarsat.org
7.4.3 Tracking and messaging systems – ARGOS
Argos is a system of Low, Earth Orbiting (LEO) satellites and the result of a joint venture
between the French and American governments. Argos provides geo-positioning services
worldwide. As well as supporting environmental related programs it also supports
industrial and private use of the system. For expedition purposes the system provides the
outside world with the ’expeditions’ location and status.
Lightweight portable beacons with the ability to transmit the expedition's position, current
temperature, current time, current status (16 code facility) and signal quality are available.
The signals are relayed by the satellite to earth stations where the data is made available to
the expedition headquarters, etc. Check the cost of using such units as the Argos system is
operated on a cost recovery basis. Argos units are hired for the expedition and the French
or US system operators can e-mail the latest information to nominated contacts every time
the unit is used.
It should also be noted that it clearly states in Argos literature that clearance to
operate on the up-link frequency of the unit must be approved by the authorities in whose
country the unit will be deployed.
7.5 Power supplies
Most electronic systems require some form of electrical power to make them work – dry,
alkaline and other cell types will give minimal power output when put in a –40°C
environment. Check your equipment for battery type. Some forms of Lithium battery will
give near 100% output at these temperatures but there may be restrictions on transportation
on aircraft without special packing or conditions of carriage. Solar cells are fine with static
expeditions but tend to break when given a day’s hard sledging as they are vulnerable to
damage.. Remember some systems have internal backup batteries as well as the main
battery.
7.5.1 Batteries – field radios and portable equipment
Low temperatures can prove problematical and specifications are such that a battery which
has the same capacity as a nuclear reactor and the physical strength of a tank weighs an
inordinate amount.