at each point on the array. The radio signal was then alternately switched between the two sets of dipoles, normally through a motor-driven mechanical switch. The return signal from one set was sent through a small delay, shifting its "peak" on the operator's oscilloscope slightly to one side. Since the switching was faster than the eye could follow, the result appeared as two well formed peaks on the display. Since each lobe was slightly off center, if the target was not centered down the middle of the antenna (as a whole), one of the two return signals would have greater strength than the other. Thus the operator could keep the antenna pointed at the target simply by moving it to make both returns equal height on the display. Since the lobes were arranged to overlap only slightly, there was only a very small angle where the two returns would be equal – even slight movements of the target out of the centerline would quickly make one signal much stronger. The resulting measurement was therefore much more accurate. Conical scanning was similar in concept to lobe switching, but as the name implies it was operated in a rotary fashion instead of two directions. This allowed the operator to get a 2-D view of which direction had the strongest return, and was much easier to operate as a result. Conical scanning could only easily be used on an antenna with a single feed horn, which is only practical with microwave radars. As such systems were introduced into service, lobe switching generally disappeared. Jamming It is possible to jam a lobe switching radar with relative ease if one knows the basic operating frequencies of the radar. In the case of a lobe switching set that switches lobes 30 times a second, a jammer can be constructed to send out a weak signal on the same frequency that also varies 30 times a second, but only sends out a signal when the radar's lobe is pointed away from the aircraft – which is easily found by looking for a low point in the received signal. At the receiver end the two signals are mixed, and the additional signal from the aircraft's jammer "smooths out" the strong/weak signal that would otherwise be seen. This denies the radar angle information, and can make anything but gross angle tracking difficult. Lobe on receive only One way to