By Bill Jankowski and Lt. Mike Grochowski
USCG RDC
ANCHORAGE, Alaska - One of the unique challenges of operating in the Arctic is staying in touch. With enormous distances involved in traveling to high latitudes and the sparse population, communications is a challenge. Traditional radio circuits such as Very High Frequency and Ultra High Frequency require that the communicants be within radio line of sight with each other, which is why transmitters are frequently placed on radio towers, allowing VHF and UHF communications up to tens of miles.
In other areas of the world where the Coast Guard may be operating far from civilization, the service uses communications satellites. These are typically in a geostationary orbit, high above the equator. However, as the Healy approaches the North Pole, the ship moves out of the footprint of these satellites due to the increased thickness of atmosphere through which it must pass.
Imagine peeling an orange - if you cut straight into the orange, you quickly pass through the skin of the orange and into the pips. However, if you cut at a shallow angle, you can carve off a long strip of skin before you hit the pips. Nearer the equator, satellite communications only have to transit 100 miles of measurable atmosphere. As one moves further north or south of the equator, the angle to the satellite makes it necessary to pass through more and more atmosphere, attenuating the signal strength.
In the Arctic, the Coast Guard often falls back to the first long-distance radio technology, High Frequency. High Frequency transmissions can bounce off of the earth’s ionosphere, the charged layer of particles that shield us from the solar wind, and complete communications circuits across continents.
The U.S. Coast Guard Research and Development Center, in conjunction with the crew of the Coast Guard Cutter Healy, are taking advantage of this trip to conduct additional experimentation of HF propagation at high latitudes, taking measurements of solar activity and using those measurements to improve models of link performance with the Coast Guard’s network of repeating stations.
Lt. Mike Grochowski and Bill Jankowski from the RDC have had exceptional support from the Healy’s crew and the Coast Guard Auxiliary, who have been conducting preliminary testing throughout the summer. The entire District 17 communications team, especially the crew at Communications Station Kodiak have been supporting the testing by exercising an existing communications network.
The goal of this experiment is to validate results from a modeling project that the RDC conducted, which will then be used to assist in evaluating any potential changes to the Coast Guard's system.