If you know your desired frequency, gain, length of boom etc, then you can determine other parameters from the supplied excel sheet. For example, the author has built a short 13 element Yagi using one meter long 15 x 15 mm square Aluminum boom, elements are 4 mm hard aluminum wire.
http://df2ck.de/tech/23cm_yagi/23cm_yagi.html
It is capable of receiving the satellite's downlink practically from horizon to horizon, and despite the relatively weak downlink, it is possible to hear the downlink well before being able to access the bird with a couple of watts into a 5/8.
http://www.qsl.net/vk3jed/2m70cmant1html.html
Often one needs to improve reception of a particular radio or television station. One effective way to do this is to build a Yagi-Uda, or Yagi, antenna.
http://www.ee.washington.edu/circuit_archive/circuits/yagi.txt
http://www.qsl.net/n6bg/thunt/yagi.html