An example of a cage <a href="https://en.wikipedia.org/wiki/T_antenna" class="extiw" title="en:T antenna">T antenna</a> on a private residence in Omaha, Nebraska USA, used as a transmitting antenna for a <a href="https://en.wikipedia.org/wiki/amateur_radio" class="extiw" title="en:amateur radio">amateur radio</a> station in 1924.  The top antenna, made of a "cage" of six parallel wires held apart with hoop-shaped spreaders with a "cage" feeder hanging down, is the T antenna, a common type used for transmitting on the <a href="https://en.wikipedia.org/wiki/longwave" class="extiw" title="en:longwave">longwave</a> band.  The "cage" construction serves to decrease the ohmic resistance and increase the capacitance to ground, increasing the antenna current and thus the RF power radiated.   The lower antenna, consisting of 6 parallel wires resembling a "clothesline" may be a separate T antenna or may be a <a href="https://en.wikipedia.org/wiki/counterpoise" class="extiw" title="en:counterpoise">counterpoise</a> which serves as a ground for the above antenna.<br><br><p>This picture was part of an article on a campaign in Omaha by Nebraska Power Co. to remove unsafe aerials and promote safe aerial construction, after a man was killed working on an antenna.  Radio broadcasting had just begun in 1920, and enthusiastic amateur listeners all over the country were constructing elaborate wire antennas like this necessary to bring in stations from distant cities.  Often thsy used unsafe techniques such as mounting antennas on utility poles near high voltage power wiring.  This antenna was given as an example of a safe one.<br><br></p>
Caption: "<i>This aerial shows how a person who is cautious and mindful of life and property can construct an aerial with perfect safety to all concerned. Every wire, with the exception of three, belongs to the aerial system.</i>"
Jack W. Marer
1924-11
Retrieved August 2, 2014 from <a rel="nofollow" class="external text" href="http://www.americanradiohistory.com/Archive-Radio-News/20s/Radio-News-1924-11-R.pdf">Jack W. Marer, "Dangerous Aerials" in <i>Radio News</i> magazine, Experimenter Publications, Inc., New York, Vol. 6, No. 5,  November 1924, p. 670</a>  archived on <a rel="nofollow" class="external text" href="http://www.americanradiohistory.com/">American Radio History</a> website