Download or read book Experimental Investigation of High Frequency Antenna Arrays Having Reduced Ground Losses written by D. V. Campbell and published by . This book was released on 1972 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Compact, high frequency antennas have been combined to form efficient, closely-spaced arrays having greatly reduced ground losses. Under ideal circumstances, an array of N elements would reduce the ground loss by the factor 1/N. Experiments prove that only a small area is needed to erect an omnidirectional antenna array having significantly increased efficiency. (Author).
Download or read book Experimental Investigation of Compact Ground Based High Frequency Antenna written by D. V. Campbell and published by . This book was released on 1971 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: A compact, low silhouette, portable high frequency antenna (experimental) for ground-to-ground communication was developed, tested, and found to launch ground waves effectively. Tuning and matching can be accomplished over a large portion of the high frequency range by integrating loading inductors with the radiating element. Ground losses are minimized by exciting the radiator against a counterpoise. Feedline radiation and associated power loss are prevented by a broad-band cable choke. Radiation efficiency of the compact HF antenna is comparable to that of the much larger reference antenna. Compact HF antennas have been combined to for an efficient closely-spaced array having greatly reduced ground losses. (Author).
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements written by and published by . This book was released on 1974 with total page 1000 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ground Loss Reduction at High Frequencies Through the Use of Antenna Arrays written by C. M. De Santis and published by . This book was released on 1971 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: High frequency antenna arrays are shown to reduce the effect of conduction losses normally associated with an antenna operating on or in proximity to the surface of the earth. It is demonstrated that the normal directivity gain as a function of array element spacing is modified by the presence of the finite conducting earth, and that at the lower frequencies in the HF range the gain of the array increases rapidly as the element spacing is increased from zero (single dipole) to about 1/10 of a wavelength. At this spacing, the gain approaches a limit which for low conductivities is close to a theoretical upper bound equal to the number of elements in the array. (Author).
Download or read book Experimental Investigation of Ground Antenna Characteristics written by Jose Perini and published by . This book was released on 1966 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a report on an experimental program with the following objectives: (1) To develop a suitable antenna test range; (2) To determine how closely certain antenna array patterns can be realized and maintained with normal handling of array elements and under normal environmental conditions; (3) To study experimentally the problem of mutual coupling between array elements; and (4) To obtain preliminary experimental verification of side lobe reduction techniques for both equally and unequally spaced arrays. The antenna test range is described, and sample results are presented of measurements of the field intensity at the site of the test antenna. It is concluded that the test range is suitable for use in making antenna pattern measurements. A large amount of experimental data is presented, and the results are considered to be generally good. The patterns of the test antennas are in good general agreement with expected results, and the adverse effects of mutual coupling on the experimental patterns are discussed. Finally, the validity of various side lobe-reduction techniques is demonstrated, which paves the way for more advanced experimental studies of methods of array synthesis and side lobe reduction. (Author).
Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1984-05 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Index written by and published by . This book was released on 1972 with total page 1126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Influence of Non Homogeneous Earth on the Performance of High Frequency Receiving Arrays with Electrically Small Ground Planes written by and published by . This book was released on 1991 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance of ground-based frequency (HF) antenna arrays is reduced when the array elements have electrically-small ground planes. Performance degradations include: (1) a decrease in directive gain near the horizon (caused by earth multipath), (2) a decrease in radiation efficiency and an increase in internal noise (caused by ground losses), (3) an array RMS phase error (caused by exterior currents on element feed cables), and (4) an array rms phase error and beam pointing errors (caused by non-uniform Fresnel reflection RMS from a non-homogeneous earth). This paper models the degradation described in (4) above. Numerical results are presented for cases of randomly-distributed and systematically-distributed earth non-homogeneities where one-half of vertically-polarized array elements are located in proximity to one type of earth and the remaining half are located in proximity to a second type of earth. The maximum rms phase errors, for the cases examined, are 18 degrees and 9 degrees for randomly-distributed and systematically-distributed non-homogeneities, respectively. The maximum beam pointing errors are 0 and 0.3 beamwidths for randomly-distributed and systematically-distributed non-homogeneities, respectively.
Download or read book Keywords Index to U S Government Technical Reports written by United States. Department of Commerce. Office of Technical Services and published by . This book was released on 1962-06 with total page 1176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Scientific and Technical Reports written by United States. National Aeronautics and Space Administration Scientific and Technical Information Division and published by . This book was released on 1966 with total page 1440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications written by United States. National Bureau of Standards and published by . This book was released on 1960 with total page 762 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Supplementary List of Publications of the National Bureau of Standards written by and published by . This book was released on 1960 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications United States National Bureau of Standards written by United States. National Bureau of Standards and published by . This book was released on 1960 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications of the National Bureau of Standards written by United States. National Bureau of Standards and published by . This book was released on 1967 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications July 1960 Through June 1966 written by United States. National Bureau of Standards and published by . This book was released on 1967 with total page 770 pages. Available in PDF, EPUB and Kindle. Book excerpt:
