Ads
related to: 80 meter band linear loaded dipole
Search results
Results From The WOW.Com Content Network
The nominal "80 meter" band begins at 3.5 MHz (85.7 m wavelength) and goes up to 4.0 MHz (74.9 m wavelength).The upper part of the band, mostly used for voice, is often referred to as 75 meters, since in Region 2, the wavelengths in that section are between 80–75 meters (adjacent to or overlapping a shortwave broadcast band called by the same name: "75 m").
Also called a multi-dipole – a common broadband and / or wideband dipole variant that superficially resembles the bow-tie antenna, but is electrically different. It is a composite of pairs of dipole arms; both arms of one of the dipoles are equal-length, but each dipole pair is a different length from every other pair.
German physicist Heinrich Hertz first demonstrated the existence of radio waves in 1887 using what we now know as a dipole antenna (with capacitative end-loading). On the other hand, Guglielmo Marconi empirically found that he could just ground the transmitter (or one side of a transmission line, if used) dispensing with one half of the antenna, thus realizing the vertical or monopole antenna.
This simplified arrangement has several advantages, including a shorter ground distance between the ends. 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).
The nominal "17 m" band actually covers 16.6–16.5 m. The nominal "15 m" band actually ranges from 14.28–13.98 m. By common sense, the "15 m" band ought to be called "14 m", but that name has been in longtime use for a shortwave broadcast band. 80 metres or 80 / 75 meters – 3 500–4 000 kHz – 85.65–74.95 m actual
Loop antenna, receiver, and accessories used in amateur radio direction finding at 80-meter (260-foot) wavelength (3.5 MHz). As long as the loop perimeter is kept below about 1 / 4 wave, the directional response of small loop antennas includes a sharp null in the direction normal to the plane of the loop, so small loops are favored as ...