English: Transmitting
antenna of
amateur radio station 2BML and 2EH in 1922, belonging to the Radio Engineers Club of Riverhead, New York, USA. This type of wire antenna, called a cage
T antenna, was commonly used for transmitting on
MF and
LF frequencies. It consists of a conductor in the form of a "T", 60 ft high and 90 ft wide, suspended beween two masts. The conductor is made of a "cage" of six parallel wires held apart with wood spreaders. The vertical line extending upward from the transmitter shack radiates the radio waves, while the horizontal part is a capacitive "top-load" which increases the current in the vertical part. The multiwire "cage" construction serves to increases the capacitance to ground and decrease the resistance, further increasing the antenna current and radiated power. The ground of the transmitter was attached to a "
counterpoise", a horizontal wire suspended a few feet above the ground under the antenna. It achieved transatlantic contacts to Scotland on 200 meters (1.5 MHz) at a radiated power of 440W. The antenna resistance is 7 ohms and the efficiency is 67%.
Alterations to image: Removed dark tint to sky in left side of photo using GIMP editor, and colorized
This recently colorized version of an original black and white (greyscale) photograph is
WP:ORIGINAL RESEARCH and should not be used in Wikipedia articles; the original black and white photo
Amateur T cage antenna 2BML 1922.jpg should be used instead.