雨傘礦石收音機遊日本大阪
本帖最後由 cheungbx 於 4-6-2013 20:19 編輯帶了雨傘礦石收音機遊日本大阪,在大阪城中波接收訊號強, 4 個當地電台,都很大聲.
Video link
http://v.youku.com/v_show/id_XNTY0NjU0NjIw.html
雨傘礦石收音機做法見
http://www.crystalradio.cn/thread-408183-1-1.html
也在酒店的房內用衣架構做了個簡易大環礦機,同様收到了4個當地電台.
也試了剛做的FM礦機,在香港收不了台,在大阪巿中心竟然收到3個台,聲小但是以及人聽清楚.
FM礦機電路
Video Link
http://v.youku.com/v_show/id_XNTY0NTk5NTM2.html
真厲害，你的礦石機選擇性很好，音質佳。
FM礦機在日本收到卻在香港收不到，很可能礦機的接收頻率偏低，因日本FM電台頻率是76MHz~90MHz而香港是88MHz~108MHz，試試減少線圈圈數看能否收到本地電台。 能否說—說 FM 礦石收音機的電路是怎樣把FM解調呢，讓我學習—下。謝謝！ 謝謝你的意见. 我改了個线路用直接單二极管极管检波,现可在香港也收到FM矿石机了.FM矿机的检波原电路和中波的一樣,只是加上了High Frequency Choke coil. 原理是斜率检波.
FM modulates by shifting frequency from a central broadcasting frequency.
Hence, we can use the same crystal radio circuit used in AM/MW crystal radio to turn the radio signal into audiable signal, the difference is AM/MW modulates by amplitude directly, FM modulates by shifting frequency back and forth from a central frequency. With FM crystal radio, this frequency shifting will also indirectly translate into a form of shifts in amplitude. Since off-tuned radio signal will be lower in volume by theory. This lower and higher volume will become the audiable signal.
香港玩矿机的人太少.了.没机會交流.
我都是從內地Discussion Forum 學的.
我也做了這個FM矿机,在高樓伸出窗外便收到,不用天地线.
http://www.crystalradio.cn/forum.php?mod=viewthread&tid=73497
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