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Baker Lake, NWT
Baker Lake is part of a meridional chain of six observatories running from Gillam, Manitoba, in the south to Resolute Bay in the north. These are: Gillam, Churchill, Arviat, Baker Lake, Taloyoak, and Resolute Bay. For periods of time, identical receiving instrumentation has been operated simultaneously at all six sites. See Data Availability Chart.
Three example results from this chain:
Instrument: Dartmouth Programmable Frequency Receiver (PFR) | Top
This receiving system consists of a loop antenna of approximately 10 square meters. The antenna response is a dipole, with the null in the horizontal plane oriented such as to eliminate the largest source of local interference. A low-noise preamplifier at the antenna has frequency response 100 kHz to above 5 MHz, and transmits these signals through a 50-ohm coaxial cable to the observatory as little as a few hundred feet or as much as a mile away, depending on the station.
The PFR is a superheterodyne receiver tunable to 0-5 MHz using IF frequency of 10.7 MHz and crystal filter with bandwidth 7.5 kHz. The local oscillator is controlled directly by a PC running DOS. In the standard mode, frequency is stepped from 30 kHz to 5 MHz in 10-kHz steps, repeating the 498-frequency sequence each 2 seconds. Other programs are used on occasion, including faster frequency switching. In the standard mode, data are collected 20-24 hrs/day, archived on disk in the PC at the station, backed up onto CD-ROM monthly by a local operator, and mailed to Dartmouth (except at Arviat and Taloyoak, where data are backed up annually onto tape by visiting personnel from SED Inc.)
For more information, see Weatherwax, A.T., Ground-based observations of auroral radio emissions, Ph.D. thesis, Dartmouth College, Hanover, N.H., 1994.
Selected Publications | Top
66. LaBelle, J., Review of recent ground-level observations of terrestrial auroral radio emissions, Planet. Radio Emissions IV, ed. by H.O. Rucker, et al., Austrian Acad. Sci. Press, p. 283, 1997.
70. Hughes, J., and J. LaBelle, The latitude dependence of auroral roar emissions, J. Geophys. Res., 103, 14910, 1998.
76. Shepherd, S.G., J. LaBelle, C.W. Carlson, and G. Rostoker, The latitudinal dynamics of auroral roar emissions, J. Geophys. Res., 104, 17217, 1999.
87. Greenberg, E.M., and J. LaBelle, Measurement and modeling of auroral absorption of HF radio waves using a single receiver, to appear in Radio Sci., 2002.
90. LaBelle, J., and R.A. Treumann, Auroral Radio Emissions, 1. Hisses, Roars, and Bursts, to appear in Space Sci. Rev., 2002
Also Note: Most abstracts are freely available through NASA's Astrophysics Data System Bibliographic Services (ADS). Some are available locally. Full texts are only available to users within institutions that subscribe to the corresponding web-based journal.
Photos | Top
Photos courtesy of Larry Newitt
Photos courtesy of Peter Balagus