[attach]5921[/attach]
From http://web.cm.nctu.edu.tw/Chinese/seni/dm/story2.htm
This model portrays a typical beam pattern of such an acoustic transducer (theoretical). The term “dB” corresponds to the widely used “decibel” term which permits the values to be expressed in a logarithmic way. Thus, the power at the 20-DB radiated along that angle would be 100 times less than the amount transmitted directly on the “beam”. Also, as in optics and microwaves, “minor lobes” are always present.作者: bx4abc 時間: 2012-3-2 22:31
想請教一下
定向天線平常是要怎使用? 知道對方的方位就還好,拿指北針、地圖量一下就知道
但如果是不知道方位的呢? 轉動天線去試能否接收信號嗎?