Photocopy of a valid restricted certificate of competency in radiotelephony of the radiotelephony operator on board 船上无线电话操作人员的有效限用无线电话资格证书影印本。
3.
Methods of measurement for radio transmitters ; part 4 : amplitude frequency characteristics and non - linearity distortion in transmitters for radiotelephony and sound broadcasting 无线电发射机测量方法.第4部分:无线电话和播音发射机
4.
Methods of measurement for radio transmitters . part 4 : amplitude frequency characteristics and non - linearity distortion in transmitters for radiotelephony and sound broadcasting 无线电发射机的测量方法.第4部分:无线电话和播音发射机的幅频特性及非线性失真
