Mar 14th, 2009, 07:17
|
只看该作者 #197 | |
|
Member
 
注册日期: Jul 2004
帖子: 58
声望: 108
 |
引用:
Important: Grounding At this point you must ground the antenna to protect your valuable HDTV equipment from electrical surges. First, make sure all of your gearis plugged into a quality surge protector, preferably one that's guaranteed for at least the amount of your equipment cost. Then attach a coax grounding block, available at any RadioShack, to a point near where the cable enters the building. Connect one length of your coax antenna cable between the block and antenna and a second length between the other end of the block and your HDTV receiver. Then run a length of grounding wire from the block to a suitable grounding point. Grounding points can be a true earth ground (defined as a length of pipe driven 8 feet or more into the ground) or a cold-water pipe. The best place to find true ground is at an electrical sub-panel, comms wiring closet or the building construction steel itself. If you use a pipe, make sure to remove any paint at the point to which you attach the grounding wire. Since in new construction many pipes are PVC along some of their lenghts instead of metal, they may not be reliable grounds. You also need to ground the antenna itself by running another length of grounding wire between the antenna and ground point. Your antenna itself may have special instructions for grounding; if so, be sure to follow them. If you're not sure you've grounded your antenna correctly, consult a professional experienced in installing antennas or the manufacturer of your antenna itself. With your antenna safely installed, you can now enjoy free over-the-air HDTV. 我已经用了coax grounding block,但看来还要ground the antenna itself by running another length of grounding wire between the antenna and ground point.请大虾指教这个是否必要. |
|
|
|
|
Mar 15th, 2009, 18:42
|
只看该作者 #198 |
|
Senior Member
 
注册日期: Jul 2004
帖子: 1,134
声望: 1990834
 |
需要单独的地线是房屋，还是布线的什么code定的，至少在美国是这样，必须遵守，这东西就和法律规定一样。否则一旦因雷击失火，保险公司不赔。另外会不会有连带责任就不知道了。 另外卫星天线据说也有同样的要求，但是据我估计没有几个直接把天线接地的。甚至还有不少coax都不接地的。好像也没有太大问题。 因雷击而起火的新闻，这几年我从来没有见到过。电坏电视机，到还是有可能的。在进线上装一个surge protector可能也将就，不过我没有试过，不知道是否会把信号衰减得太多。 总之，按规矩办最放心了。我的看法从技术角度看，不是一定要装一个单独的地线的，用其他办法效果也查不太多。但是从法规，规定的角度看，是一需定要的。法规考虑的即使是极小概率的情况也不能出事。比如说按规定grounding block一定要装在室外，但实际上，相当多的房子都把这装在室内。基本上所有的cable的grounding block也都是被直接装在室内的，按道理说也都是不对的。 |
|
|
|
|
感谢 cbitmap 此篇文章之用户： |
snk (Mar 16th, 2009) |
