| 摘要 |
PROBLEM TO BE SOLVED: To obtain a low noise down converter (LNB) in which radio wave is preventing from leaking or intruding through a housing by sharing the earth commonly, and to provide a method for assembling an LNB in which a circuit board is prevented from being damaged when it is fixed while lessening the influence of a received radio wave from a signal line onto the peripheral circuit part. SOLUTION: A circuit board 10 is contained fixedly in a housing 9 made of a conductor and the opening is closed with a frame cover of conductor to produce an LNB board unit. A rib 8 provided on the bottom face of the housing 9 is inserted into a slit made in the circuit board 10 and projected to the upper side thereof thus constituting a wall for partitioning a signal line 7 and the peripheral circuit part. Since an earth electrode 21 on the surface of the circuit board 10 and the housing 9 are equipotential through a rear electrode 23, earth can be shared entirely when the housing 9 is fixed to the chassis of the LNB body by means of screws, or the like.
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