The trick turns your head into an antenna, says Tim Pozar, a Silicon Valley radio engineer.

这个 技巧把你的头作为天线，硅谷的无线电工程师蒂姆·波扎尔说。

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Another trend indicates growth in spam originating outside the U.S., according to Pozar, who cited South Korea as one of the current countries of choice for foreign spammers.

CNN: Next wave of attacks against spammers underway