However, the transmitters have a limited range, and so for a time along the forestry roads near the Nanshih River and the Tunghou River, one could often see someone driving back and forth through the mountains for no apparent reason.
不過發報器接收範圍有限，因此在沿著南勢溪、桶後溪林道，常可以看見有個人開著車沒事就在山路上繞來繞去，那正是在尋找可以收聽到黃魚鴞身上發報器傳出訊息角度的孫元勳。