Appeared in IEEE MTT Transactions, Vol.45,No.12, pp.2267-2273 (December 1997).
100 years ago, just a few years after the first experimental demonstration of radio waves by Heinrich Hertz (1888), J.C. Bose carried out experiments at frequencies as high as 60 GHz. He invented various now-commonplace microwave components. The experiments were described in the professional scientific literature of the day. This article is based on material presented to the IEEE MTT-S International Microwave Symposium in June 1997, and includes photographs of some of his original equipment, taken at the Bose Institute in Calcutta.
The Stage is Set: (PDF File).
Presented to the GLOBECOM-2001 meeting of the IEEE Communication Society in San Antonio, Tx, November 2001.Developments before 1900 Leading to Practical Wireless Communication. An account of the experiments of D.E. Hughes, demonstrating wireless transmission nearly a decade before Hertz, is included.
The AMSAT Journal, Jan/Feb 1997, Vol.20, No.1, pp.1,4-11.
QST, published by ARRL. Part 1, Vol 80, No.6, June 1996, p.32-35. Part 2, Vol 80, No.7, July 1996, p.28-31.
QST, published by ARRL. Vol 79, No. 2, February 1995, p.21.
QEX, (published by ARRL) January 1994, p.17-24. Also appeared in the proceedings of the 11th AMSAT-NA Annual Meeting and Space Symposium, 1993, p.144. (published by ARRL).
The AMSAT Journal, Vol 18, No. 1, pp. 14-17, Jan/Feb 1995.
Antenna Compendium Volume 4, pp. 64-68, 1995. (ARRL)
Antenna Compendium Volume 5, pp. 87-99, 1996. (ARRL).
QST, Vol 81, No.6, pp.43-44, June 1997. Published by the ARRL.
The twelfth-wave transformer is a convenient alternative to the well-known quarter-wave transformer. This transformer uses two twelfth-wave lengths of cable, of impedances equal to the two impedances being matched. This normally means that, unlike the quarter-wave transformer, the characteristic impedances of the matching cables are quite standard.
I have collected together some of the correspondence with readers of the Twelfth-Wave Transformer article, in an attempt to clarify some issues.
Last changed April 29 2003
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