[v = 144 m/s θ = 33.7°] 7. How high above the person's head is the roof? The antenna? [roof: 59.5 m, antenna: 66.4 m] 8.
Yesterday, Dubai celebrated the opening of the world's tallest skyscraper -2,717 feet - more than half a mile high. But Dubai's glory is North Dakota's downfall. The KVLY television tower has for years held the title of the world's tallest structure, 2063 feet, rising out of the plains of Eastern North Dakota.
However in 2019, the top mount VHF antenna was removed for the FCC spectrum repack, dropping the height to 1,987 ft (605.6 m).
| KVLY-TV mast |
|---|
| Completed | August 13, 1963 |
| Owner | Gray Television |
| Height | 605.6 m (1,987 ft) |
| Design and construction |
NCC 2016 definition of effective height : “the vertical distance between the floor of of the lowest storey included in the calculation of rise in storeys and the floor or the topmost storey (excluding the topmost storey if it contains only heating, ventilation, lift or other equipment, water tanks or similar service
Television- and radio-transmitting towers are among the tallest and most fragile structures built, with some up to 2,000 ft. (609.60 m) in height.
The top of the net is 2.43 m (8 ft 0 in) above the center of the court for men's competition, and 2.24 m (7 ft 4 in) for women's competition, varied for veterans and junior competitions. The minimum height clearance for indoor volleyball courts is 7 m (23 ft), although a clearance of 8 m (26 ft) is recommended.
The tallest radio tower is the 650 ft (198 m) KSZR (97.5) tower in Oro Valley near Tucson.
The volleyball court is surrounded by a free zone. The free zone is the area outside the court that players may enter to make a play on the ball. The free zone should be at least 3 meters wide from the court.
Volleyball characteristics
| Circumference cm (inches) | Mass grams (ounces) |
|---|
| Standard indoor | 65-67 (25.5-26.5) | 260-280 (9.2-9.9) |
| Youth indoor | 63-65 (25-26) | 260-280 (9.2-9.9) |
| Beach | 66-68 (26-27) | 260-280 (9.2-9.9) |
The Attack line is the line that separates the front court(the area near the net) and the back court(the area between the attack line and end line. The Service area is the area beyond the service line where players serve the ball.
A volleyball antenna gives players and the referee a visual aid to judge if a ball is in play or out of bounds as it flies over the net. Choose between 2 fiberglass options in recreational folding or official competition styles.
If the ball makes contact with the antenna or ANYTHING outside of the antenna, the ball is dead and considered out.
In volleyball the ball must pass over the net between the sidelines, by using antennas a line judge or referee can clearly determine whether the ball travelled round or even over the antenna when crossing the net. If something like this does occur a fault would be called.
About Indoor Volleyball. Volleyball is an indoor non-contact team sport in which two teams have three hits to pass a ball over a dividing net. The aim of the game is for each team to send the ball to the opposing team's court. A team can hit the ball three times to return it to the opposing team.
1. The antenna is a vertical rod that is located on the top of each end of the volleyball net. The two vertical rods are usually red and white in color and are mounted on the ends of the net, above the sidelines and not in-play. The antennas are usually only used for indoor play and not on outdoor nets.
The height of an antenna has a major impact on its performance. Aspects including the feed impedance, radiation diagram, radiation losses, distance from interference, reduction in possibility of exposure to RF radiation, etc.
Reduction in the height of antennaFor the transmission of radio signals, the antenna height must be multiple of λ/4 ,where λ is the wavelength . Thus, modulation reduces the height of the antenna .
Base-station antenna height (h1) = 30.48 m (100 ft) Base-station power at the antenna = 10 watts (40 dBm) Base-station antenna gain Gt = 6 dB above dipole gain (6 dBd)
Antenna gain is the ability of the antenna to radiate more or less in any direction compared to a theoretical antenna. If an antenna could be made as a perfect sphere, it would radiate equally in all directions.
