Base of <a href="https://en.wikipedia.org/wiki/mast_radiator" class="extiw" title="en:mast radiator">antenna mast</a> of AM radio station KTBS (now KEEL) in Shreveport, Louisiana, USA, showing a <a href="https://en.wikipedia.org/wiki/counterpoise" class="extiw" title="en:counterpoise">counterpoise</a> ground screen.  The ground screen is a network of horizontal radial copper wires extending out from the base of the mast, suspended on posts above the white <a href="https://en.wikipedia.org/wiki/helix_house" class="extiw" title="en:helix house">helix house</a>, attached to the antenna's ground system.  Its purpose is to prevent excessive ground currents, reducing transmitter power dissipated in ground resistance. A <a href="https://en.wikipedia.org/wiki/counterpoise" class="extiw" title="en:counterpoise">counterpoise</a> is similar to a ground screen but extends out further, up to a quarter-wavelength, replacing the ground wires entirely.<br><br>
Alterations to image: lightened dark areas to bring out ground screen more clearly against sky.
Edmund A. Laport
1952
Retrieved from  <a rel="nofollow" class="external text" href="http://snulbug.mtview.ca.us/books/RadioAntennaEngineering/">Edmund A. Laport, <i>Radio Antenna Engineering</i>, McGraw-Hill Publishing Co., New York, 1952, p. 54, fig 1.14</a> on David Platt's webpage for this book