2010_04_11b_wbz_148 : 無料・フリー素材/写真
2010_04_11b_wbz_148 / Nfrastructure
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
|---|---|
| 説明 | WBZ's two towers in Hull, Massachusetts. The towers are phased to create a single deep null straight east (behind the right tower) toward the Atlantic Ocean, and increase strength beyond the station's 50,000 watts in other directions, especially toward the west. (Technical details, including a picture of the pattern, are www.fccinfo.com/CMDProEngine.php?sCurrentService=AM&t....) Standing in a salt water marsh surrounded by sea water on nearly all sides is also to the station's advantage, since salt water has maximum ground conductivity, which is essential for AM coverage. New England's ground has notoriously low conductivity, so having a good transmitter location is essential. WBZ's could hardly be better. The towers are 519.36 feet high, an electrical length of 188.5°, or somewhat longer than half-wave, or 180°, for its frequency of 1030Khz. This further concentrates energy along the ground.The tower height in fact is actually due to having been built for the station's original frequency of 990KHz, for which the towers were an exactly half wave. Read more about this landmark AM broadcast facility in Scott Fybush's 2005 report, which begins here. |
| 撮影日 | 2010-04-11 16:27:55 |
| 撮影者 | Nfrastructure |
| タグ | |
| 撮影地 | |
| カメラ | Canon EOS 5D , Canon |
| 露出 | 0.004 sec (1/250) |
| 開放F値 | f/9.0 |
| 焦点距離 | 28 mm |