用于某电台的FD-71管,三栅有较严重的二次电子发射,引起电台输出信号失调,造成通话无声的所谓“阻塞”现象,使电台工作失灵。经多次试验,获得了抑制三栅二次发射的有效方法,并对原报废的管子进行了返修复活工作,效果良好。经电台反复试验表明,凡与三栅二次发射系数δ=1(Ig8=o)相对应之三栅电压Ug_(30)小于135伏的管子在电台上工作就失灵,而 ED-71 FD-71 for a radio station, the tri-grid has more serious secondary electron emission, causing the radio output signal imbalance, causing the call so-called “blocking” phenomenon, the radio work failure. After several tests, an effective method of inhibiting the secondary emission of the tri-grid was obtained, and the originally scrapped pipe was reworked and worked well. Repeated tests conducted on the radio indicate that tubes with a triple-gate voltage Ug_ (30) of less than 135 volts corresponding to the quadratic emission coefficient δ = 1 (Ig8 = o) of the tri-