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For example, a dipole antenna for the 80 meter band requires a ground length of about 140 feet (43 m) from end to end. An inverted vee with a 40-foot (12 m) apex elevation requires only 115 feet (35 m). For radio amateurs living on small parcels of property, such savings can make it possible to use the lower frequency amateur bands.
Louis Varney (G5RV) invented this antenna in 1946. [4] It is very popular in the United States. [5] The antenna can be erected as horizontal dipole, as sloper, or an inverted-V antenna. With a transmatch, (antenna tuner) it can operate on all HF amateur radio bands (3.5–30 MHz). [5] [6]
Inverted-'V' antenna When the two arms of a dipole are individually straight, but bent towards each other in a 'V' shape, at an angle noticeably less than 180°, the dipole is called a 'V' antenna, and when the dipole arms' end closer to the ground than their center branch-point, the antenna is called an inverted-'V' . The inverted-'V' is ...
A 20-meter-long T²FD antenna, covering the 5-30 MHz band. The T ilted T erminated F olded D ipole ( T²FD , T2FD , or TTFD ) or B alanced T ermination, F olded D ipole ( BTFD ) - also known as W3HH antenna - is a general-purpose shortwave antenna developed in the late 1940s by the United States Navy .
The vertical plane is used to plot an antenna's relative field strength perpendicular to the ground (which directly affects a station's coverage area) on a polar graph. Normally, the maximum of 1.000 or 0 dB is at the side (unless there is beam tilt ), which is labeled 0°, to 90° at the top and −90° at the bottom.
The best TV antennas deliver shows, sports, news and movies, with no monthly bills. Here are the best HDTV antennas on the market. The best TV antennas of 2022: Tested and rated
Vivaldi antennas are useful for any frequency, as all antennas are scalable in size for use at any wavelength. Printed circuit technology makes this type antenna cost effective for microwave frequencies 1 GHz or higher. An inexpensive Vivaldi antenna is etched upon a printed circuit board and fed with a soldered-on coaxial cable and SMA connector.
The antenna's feed point is at the center of the disc. It is usually fed with 50-ohm coaxial cable, with the center conductor connected to the disc, and the outer conductor to the cone. The cone: The length of the cone should be a quarter wavelength of the antenna's lowest operating frequency. [2] The cone angle is generally from 25 to 40 degrees.