http://www.engr.sjsu.edu/rkwok/projects/UWB_antenna.pdf
How to convert a standard book-size battery-powered shortwave receivers to directional reception to reduce interference. Easy construction - can be home-built.
http://www.hard-core-dx.com/nordicdx/antenna/special/reducin1.html
basics of antenas and most commonly used antenna types.
http://www.personaltelco.net/index.cgi/AntennaInfo
Calculate quarter, half, and full wavelength.
http://www.k1dwu.net/antennacalc.phtml
There is significant impedance mismatch between most shortwave antennas and the receiver. With this antenna matching device you will get maximum signal to the receiver at most frequencies.
http://www.hard-core-dx.com/nordicdx/antenna/special/2010ant.html
Covers these antennas: arrays, corner-reflector, dipole, folded-dipole, ground-plane, long-wire, rhombic, turnstile, Vee, and Yagi-Uda.
http://www.tpub.com/neets/book10/42.htm
Radiation patterns and other properties for these antennas: dipole, horn, loop (circular and square), parabolic, whip, and Yagi-Uda.
http://www.rfcafe.com/references/electrical/antenna_patterns.htm
Various doule quad, yagi, parabolic dish, slot and horn antenna with nice picture.
http://lea.hamradio.si/~s51kq/ANTENNA.HTM
http://www.ee.surrey.ac.uk/Personal/D.Jefferies/antennas.html
Describes many different designs. Worth take a look.
http://www.qsl.net/on7yd/136ant.htm