In the David and Goliath(大卫与歌利亚，以弱胜强的典故) war between Ukraine and Russia, drones have proved a great equaliser(平衡器；使势均力敌的事物). Ukraine’s short-range aircraft are cutting Russia’s supply lines to its occupying(占领的；占据的) troops, while long-range versions attack oil refineries, airfields and warehouses as far afield as(远至……；远达……) Siberia.
在乌克兰与俄罗斯这场“大卫与歌利亚”式的战争中，无人机被证明是极好的平衡器。乌克兰的短程无人机正在切断俄军占领部队的补给线，而远程型号则攻击远至西伯利亚的炼油厂、机场和仓库。
Not all military drones, however, carry warheads(弹头). Many are used instead for spying and target location. A lot of these gather their data at optical or infrared frequencies. But some, involved in the field of signals intelligence, or SIGINT, listen out for(留心听；注意监听) radio waves. And within that category are those which seek not to understand what is being broadcast, but merely to identify and locate its source, the better to attack it—a field of endeavour called electronic support measures (ESM).(而在这一类别中，有些无人机并不试图理解广播内容，而只是识别并定位信号源，以便更好地攻击它——这一领域被称为电子支援措施（ESM）。)
然而，并非所有军用无人机都携带弹头。许多无人机被用于侦察和目标定位。其中大部分在光学或红外频率上收集数据。但有些无人机属于信号情报（SIGINT）领域，专门监听无线电波。而在这一类别中，有些无人机并不试图理解广播内容，而只是识别并定位信号源，以便更好地攻击它——这一领域被称为电子支援措施（ESM）。
According to Thomas Withington, an electronic-warfare expert at the Royal United Services Institute(皇家联合军种研究所，英国防务智库), a think-tank, the result has been an arms race in which the radio frequencies used to control drones have migrated(迁移；转移) ever further up and down the spectrum, in attempts to(试图；为了) evade(躲避；逃避) detection. Frequency-hopping radios, which skip from one wavelength to another thousands of times a second, are getting faster, so a transmitter may be visible only momentarily; signals are increasingly disguised to merge into background noise.(跳频电台每秒在数千个波长之间跳跃，速度越来越快，因此发射机可能只在一瞬间可见；信号也越来越多地被伪装，以融入背景噪声。)
智库皇家联合军种研究所的电子战专家托马斯·威辛顿表示，其结果是一场军备竞赛：用于控制无人机的无线电频率不断向频谱的高端和低端迁移，以试图躲避探测。跳频电台每秒在数千个波长之间跳跃，速度越来越快，因此发射机可能只在一瞬间可见；信号也越来越多地被伪装，以融入背景噪声。