Daniels in the Antarctic
Daniels goes to extremes to meet customer requirements. One of our extremes has been the Antarctic. The Antarctic is renowned for its cold temperatures where lows of -50ºC (-58ºF) are common and winds can exceed 185 km/h (115 mph). A Daniels transportable VHF repeater has been operational in the Antarctic since the mid 1990s providing communications from summer research camps a mile (1.6 kms) up on the Ross Ice Shelf back to McMurdo Station.
In this harsh environment the survival of scientists and other workers in these camps (like the one in the photo to the right) requires dependable communications with McMurdo Station, more than 50 miles (80 kms) across the Ross Ice Shelf. Helicopters provide the only access to these field camp sites, and very-high-frequency (VHF) transceivers provide the only communications.
VHF transceivers have proved to work well when the line-of-sight propagation limitation is overcome with transportable mountaintop repeaters. The repeater supports multiple communications channels and meteorological equipment. The system can be assembled easily and flown to the repeater site. At the site, the repeater is unhooked from the lifting rigging, the antenna and accessory cables are installed and connected, wind braces are rigged and the repeater is turned on. The system is then in operation and ready for use immediately. The open-frame structure has solar panels on all sides and an equipment case with four structure-leveling jacks, four deployable outriggers, and equipment shock protection (see photo below.) The equipment case contains a 19-inch equipment rack, the Daniels VHF repeater, the solar power subsystem the meteorological monitoring subsystem and the RF distribution subsystem.
The Daniels repeater includes a receiver, transmitter, 30 Watt power amplifier operating in the 136 – 150 MHz band and an audio control card. The solar power subsystem is composed of four 83W solar panels, a 30A charging controller, two adjustable low voltage disconnects and six sealed lead-acid (gelled) batteries. Each solar panel (side-mounted, to maximize sunlight incidence) provides power to the charging controller and then to the 12Vdc bus and storage batteries.
Since its first season (1993-1994) of deployment the repeaters have performed flawlessly and carry both aircraft and field party communications. For more information on how Daniels can meet your requirements for transportable repeaters contact the sales department at Daniels. .
This story is extracted from an article written by Tom Reiff for Mobile Radio Technology Magazine.