@article{0c104d60a4de4a2aa657c3818d95fba5,
title = "A short history of geophysical radar at Arecibo Observatory",
abstract = "As Arecibo Observatory (AO) approaches its 50th anniversary, it is appropriate to review the many radars and ionospheric heaters that have been deployed on or near the 305 m dish and to summarize some of the innovative radar-based geophysical research that has resulted. The reasons William E. (Bill) Gordon developed the 305 m Arecibo dish are well known but are briefly reviewed. The early and then more recent radar/feed designs are reviewed as geophysical uses of Arecibo have evolved and as the full potential of the dish and nearby facilities was and is being realized from HF through S-band frequencies. This history surely has some gaps and there are a few mysteries. The community is encouraged to fill these gaps and to help complete the history.",
author = "Mathews, {J. D.}",
note = "Funding Information: Acknowledgements. The author gratefully acknowledges the following individuals for their input to this history: K. L. Bowles, D. B. Campbell, H. C. Carlson, D. F. Farley, S. Gonzalez, J. B. Hagen, T. W. Thompson, J. R{\"o}ttger, R. M. Robinson, Carmen G. Segarra-Saavedra, and M. P. Sulzer. Monica S. Mathews capably edited the many versions of this paper. The author also acknowledges the amazing opportunities, friends, and colleagues afforded him through his long – now nearly 44 yr – association with Arecibo Observatory and its staff. This association was due in large part to the kind and continuous funding from NSF for use of Arecibo Observatory in the author{\textquoteright}s research activities. This particular effort was supported under grants ATM 07-21613 and ATM 12-02019 to the Pennsylvania State University. Funding Information: The success of the original Bowles radar (Bowles, 1958) likely led to the decision to include a similar radar at AIO, though this is speculation and the mystery as to why this radar was installed at AIO remains. The proposal for this system was sent to AFOSR in early August 1962 and it was funded by 29 August 1962 (Gordon, 1962b). This radar, designed and built for AIO under ARPA funding (Gordon, 1962a), was initially to be installed in July 1964 but ultimately was commissioned in June 1965 (Gordon, 1965). This system employed four four-element Yagi antennas symmetrically arrayed around the 430 MHz feed at the appropriate position below the paraxial surface, as shown in Fig. 5. The peak antenna gain was 36.9 dBi and transmitted power was 1.2 MW peak (50 kW average power) with the power supply and actual transmitter located adjacent to the 430 MHz klystron and power vaults with RF delivered to the carriage house via 6-inch co-axial cable (Campbell and Muhleman, 1969; Thompson, 1970). Publisher Copyright: {\textcopyright} 2018 Copernicus GmbH. All rights reserved.",
year = "2013",
month = mar,
day = "13",
doi = "10.5194/hgss-4-19-2013",
language = "English (US)",
volume = "4",
pages = "19--33",
journal = "History of Geo- and Space Sciences",
issn = "2190-5010",
publisher = "Copernicus GmbH",
number = "1",
}