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

68 RGS-IBG Polar Expeditions Manual
VHF portable radios have a limited range of only a few miles over the ground,
subject to topography, but they can be used to speak to aircraft at greater distances. The
lack of scheduled airline traffic over the polar regions for the most part, means that this
system can only be used with accurate planning and agreements prior to departure.
The above systems are only as efficient as the person using them. It is
recommended that personnel be trained in all aspects of the above systems, to a level
where actions are automatic.
7.3.2 The ionosphere
The layers of ionised gases ranging from 90–600km above the earth are used as a reflective
medium for short wave radio signals.
Communications in the polar regions are extremely difficult due to the effects from
solar storms and the particles the sun emits being focused in the polar regions. This can
cause radio black outs or severe attenuation of radio signals for hours or days on end.
7.3.3 Radio procedures
• Check all equipment is connected properly; look for snow and ice in plugs and
sockets. Check security of wires and battery terminals;
• Set up your aerial with care as this has a great effect on reception. A dipole aerial
should be as far off the ground as possible (and connected by paracord to the ski
stick (or other stick) so it is not earthed. Make sure it is perpendicular to the
direction of transmission. Also make sure you have the dipole length suited to the
frequency in use;
• Double check frequency and mode, i.e. (LSB, USB, AM, FM);
• Always keep to your planned schedule time and frequency;
• Keep your transmissions short and to the point, don’t waffle;
• Discuss fully with your air charter company about pilot radio procedures for a pickup
situation.
7.4 Satellite communications
Long range communications in polar regions have generally relied on HF (short wave)
transmissions but these may suffer from temporary blackouts of up to a few days caused by
sunspot activity. Developing technology has brought down the size and cost of satellite
communications systems and made them a viable option for groups operating in polar
areas.
7.4.1 Iridium satellite communication system
Introduced in the late 1990s, the iridium satellite communication system offers very
reliable 24 hour coverage all the way to both the North and South Poles. A large number of
government operators, science and expedition teams use the iridium system in preference
to HF (shortwave) radio links. Iridium phone handsets are small, light and easily powered
from lithium cells or recharged with a solar panel.