Affinity were approached by British Antarctic Survey (BAS) to provide a suitable Microwave Link solution to aid their research work. The extreme environment of the winter months in Antarctica presented some challenges for reliability of operation.
After some engineering consultation with Karen Fowler – Communications Engineer at BAS, a solution from affinity partner SAF Tehnika was chosen to fulfill the requirement. A 1.4Ghz Marathon 11 microwave link featuring a totally passive antenna was seen as ideal, due to its relative ease of alignment, long range, excellent pedigree, and the fact that it does not possess any outdoor (ODU) electronics.
An antenna was mounted on the Halley VI research station, to provide wireless backhaul from the connecting antenna on a movable sled (seen in the picture below). Some initial profile work using what terrain based mapping exists for Antarctica with the help of SAF was undertaken for links ranging from 10 – 15km at different positions on the ice shelf.
Due to the location of the work, affinity engineers provided installation training for BAS engineers on the SAF equipment, prior to shipment out to Antarctica. On arrival in Antarctica the equipment was deployed for the first winter, and the results assessed.
Microwave Link – Assessing Results
Although connectivity was stable, the performance left us with some room for improvement. A conference call was suggested with SAF Tehnika, a member of our engineering team, and the communications team at Norfolk Constabulary (existing users of Marathon SAF equipment). They very kindly offered their help.
Due the unique nature of the environment the team suspected two possible issues. The received signal level (RsL) was being reduced by unseen ice obstructions, or a natural phenomenon know as ‘ducting’ was occurring due to the strong nature of the earth’s magnetic field at this latitude.
The team suggested a connecting cable change at Halley to reduce signal loss, and to consider the use of a larger 0.9m grid antenna. This was duly implemented and the results were very positive with much improved throughput. The link operated un interrupted through the following winter in antactica.
The Halley V1 research station was recently moved due to the northern movement of a chasm in the Brunt Ice Shelf (which had previously been dormant for around 35 years). The move was completed but a second crack (known as the Halloween crack) has appeared unexpectedly in October 2016, and continues to extend eastwards. Access to the station remains very difficult at present and a decision not to man the station in the winter of 2018, has been taken on safety grounds. Research will continue in the summer months affinity understands.
Affinity are an Independently owned, technology company founded in 2001 by entrepreneurial director’s. affinity provides wireless bridge and wired network infrastructure for clients throughout the UK. Our team of expert people provide the consultancy, design and support services our clients need to make technology work in their business. For more information visit www.affinity-comms.co.uk
About British Antarctic Survey
British Antarctic Survey (BAS), an institute of the Natural Environment Research Council (NERC), delivers and enables world-leading interdisciplinary research in the Polar Regions. Its skilled science and support staff based in Cambridge, Antarctica and the Arctic, work together to deliver research that uses the Polar Regions to advance our understanding of Earth as a sustainable planet. Through its extensive logistic capability and know-how BAS facilitates access for the British and international science community to the UK polar research operation. Numerous national and international collaborations, combined with an excellent infrastructure help sustain a world leading position for the UK in Antarctic affairs. For more information visit www.bas.ac.uk