How Antennas Work

... loss–RF waves tend to spread away from the source of the signal (the antenna) 1 7How Antennas Work Understanding antennas requires in-depth knowledge of physics, mathematics, and electronics 18Summary•Gain ... larger antennas 10Antenna Sizes and Shapes (continued)•Omnidirectional antennas Used to transmit and receive signals from all directions with relatively equal intensity–Longer...

Ngày tải lên: 13/09/2012, 10:52

... communicative objectives. 2.3. Group work in speaking lesson2.3.1. Definition of group workThere are some definitions discussing about group work: Doff (1988:137) defines group work as a process that “the ... pairs and group work in English speaking lesson into account. The results did show that the success of communicative pairs and group 17 work activities is often determined by th...

Ngày tải lên: 07/11/2012, 14:50

... useless. But his coworker Art Fry used it to stick bookmarks into his hymn book. The bookmarks wouldn’t fall out, but they could be moved around. And so the sticky note was born! How long does ... 66-67 64 How much oil can the largest oil rig store? Most of the energy we use comes from burning fossil fuels. But these fuel sources won’t last forever, so we need to start thinking ab...

Ngày tải lên: 25/12/2013, 16:34

... here: favorite programs; disks on the network to which you often connect; a document you're working on every day; and so on. Folder and disk icons here work just like normal ones. You can drag ... small-office network, right there in every window, without any digging, connecting, button-clicking, or window-opening. But here it is: a complete list of the other computers on your netw...

Ngày tải lên: 21/01/2014, 04:20

... Folder trick really turns into a high-octane timesaver if you use auto completion. Here's how it works: After each slash, you can type only enough letters of a folder's name to give Mac ... right-clicking (or Control-clicking, or -clicking) the name of the window to access the menu shown in Figure 1-5 . (You can release the Control or key immediately after clicking.) By choos...

Ngày tải lên: 21/01/2014, 04:20

... Section 1.2.10 .) GEM IN THE ROUGH How Much Is That Doggie in the Window? The status bar shows you disk-space information for the entire disk, but not how much disk space this particular window's ... graphics, or music). If your monitor isn't big enough to show all the icons in a window, the zoom box resizes the window to show as many as possible. In either case, a second cl...

Ngày tải lên: 21/01/2014, 04:20

... begins allover again. How Computers Used to Work At the beginning of the 21 st century, computers are such com- plex beasts-despite their relative youth-that it's difficult to imagine how such elaborate ... larger, five-pin round port on older systems. EIJ Network Connector: The network connecter allows you to connect your PC to a local area network (LAN) or a broadband cable or DS...

Ngày tải lên: 19/03/2014, 13:35

Ngày tải lên: 28/03/2014, 20:20