Practical_Antenna_Handbook_0071639586
C h a p t e r 2 5 : A n t e n n a M o d e l i n g S o f t w a r e 557 • Terrain analysis examines the effect of nearby (i.e., within a few miles) topographic features using principles of optical reflection and diffraction. In some countries, government or private topographical databases can be downloaded for automatic use by the software. If this is not the case in your country, manual entry is always possible. Terrain analysis is of great benefit when utilized prior to determining the height or location of antennas and their supports on a specific parcel of land, but it is probably of most benefit when used even earlier to compare the relative merit of multiple candidate sites for an antenna facility. • Ionospheric propagation programs carry the ball the rest of the way, providing statistical predictions of optimum working frequencies, the probabilities and times for communicating between two points at any given time of the day, and the propagation modes providing the most efficient path between those points. In addition, some will predict received signal levels at distant receiving locations anywhere on the globe for a given transmitter power level. See Chap. 2 (“Radio-ÂWave Propagation”) for additional information regarding these software tools. Summary Despite a plethora of caveats, “gotchas”, rules, and guidelines for users, today’s accurate yet inexpensive modeling tools are a boon to antenna experimenters everywhere. Hours or even days that might previously have been spent trudging through swamps, prickly brush, or deep snowdrifts to erect yet another configuration of wires atop the trees can now be put to better use, thanks to the power of the modern personal computer and the considerable efforts and accomplishments of a dedicated group of scientists, engineers, hobbyists, and entrepreneurs. Many examples of antenna modeling results from both EZNEC (for the PC) and cocoaNEC (created by Kok Chen, W7AY, for the Mac) can be found in the chapters of this book dedicated to specific families of antennas. Any errors in the results presented are the fault of this author, not the software packages or their authors. See App. B for a list of antenna modeling software vendors and the link for obtaining an NEC-Â4 license (U.S. users only).
This page intentionally left blank
- Page 527 and 528: C h a p t e r 2 2 : R a d i o A s t
- Page 529 and 530: Figure 22.9 Interferometer pattern.
- Page 531 and 532: CHAPTER 23 Radio Direction-Finding
- Page 533 and 534: C h a p t e r 2 3 : R a d i o D i r
- Page 535 and 536: C h a p t e r 2 3 : R a d i o D i r
- Page 537 and 538: C h a p t e r 2 3 : R a d i o D i r
- Page 539 and 540: C h a p t e r 2 3 : R a d i o D i r
- Page 541 and 542: Figure 23.9 Adcock array RDF antenn
- Page 543 and 544: Figure 23.11 Watson-Watt Adcock arr
- Page 545 and 546: C h a p t e r 2 3 : R a d i o D i r
- Page 547 and 548: C h a p t e r 2 3 : R a d i o D i r
- Page 549 and 550: C h a p t e r 2 3 : R a d i o D i r
- Page 551 and 552: Tuning, Troubleshooting, and Design
- Page 553 and 554: CHAPTER 24 Antenna Tuners (ATUs) Th
- Page 555 and 556: C h a p t e r 2 4 : a n t e n n a T
- Page 557 and 558: C h a p t e r 2 4 : a n t e n n a T
- Page 559 and 560: C h a p t e r 2 4 : a n t e n n a T
- Page 561 and 562: C h a p t e r 2 4 : a n t e n n a T
- Page 563 and 564: C h a p t e r 2 4 : a n t e n n a T
- Page 565 and 566: CHAPTER 25 Antenna Modeling Softwar
- Page 567 and 568: C h a p t e r 2 5 : A n t e n n a M
- Page 569 and 570: C h a p t e r 2 5 : A n t e n n a M
- Page 571: Figure 25.3B Bent dipole wire and s
- Page 574 and 575: C h a p t e r 2 5 : A n t e n n a M
- Page 576 and 577: C h a p t e r 2 5 : A n t e n n a M
- Page 580 and 581: CHAPTER 26 The Smith Chart The math
- Page 582 and 583: Figure 26.2 Normalized impedance li
- Page 584 and 585: A Figure 26.3 Constant resistance c
- Page 586 and 587: A Figure 26.4A Constant inductive r
- Page 588 and 589: C h a p t e r 2 6 : T h e S m i t h
- Page 590 and 591: C h a p t e r 2 6 : T h e S m i t h
- Page 592 and 593: D C B A Figure 26.5 Radially scaled
- Page 594 and 595: C h a p t e r 2 6 : T h e S m i t h
- Page 596 and 597: C h a p t e r 2 6 : T h e S m i t h
- Page 598 and 599: C h a p t e r 2 6 : T h e S m i t h
- Page 600 and 601: C h a p t e r 2 6 : T h e S m i t h
- Page 602 and 603: 0.165 Y ' 1.0 j1.1 G' 1.0 Y ' 0.2
- Page 604 and 605: C h a p t e r 2 6 : T h e S m i t h
- Page 606 and 607: C h a p t e r 2 6 : T h e S m i t h
- Page 608 and 609: CHAPTER 27 Testing and Troubleshoot
- Page 610 and 611: C h a p t e r 2 7 : T e s t i n g a
- Page 612 and 613: C h a p t e r 2 7 : T e s t i n g a
- Page 614 and 615: C h a p t e r 2 7 : T e s t i n g a
- Page 616 and 617: C h a p t e r 2 7 : T e s t i n g a
- Page 618 and 619: C h a p t e r 2 7 : T e s t i n g a
- Page 620 and 621: C h a p t e r 2 7 : T e s t i n g a
- Page 622 and 623: C h a p t e r 2 7 : T e s t i n g a
- Page 624 and 625: C h a p t e r 2 7 : T e s t i n g a
- Page 626 and 627: C h a p t e r 2 7 : T e s t i n g a
This page intentionally left blank
Change language