Even when stealth technology was deadly secret and the F-117A did not officially exist, there was counter-stealth radar.
Textbooks told us radar cross-section (RCS) was frequency dependent, and tended to become increasingly so as the target shape grew more complicated. If the radar wavelength is of the same magnitude as prominent features of the target, the signal is scattered by a resonant mechanism that is unimpressed by cunning shaping or materials magic. In the 1980s, many older Russian systems operated in the VHF band, with wavelengths in the 1-2-meter range, which is about the same as the chord of a fighter’s tail surfaces and wingtips.
But, as I wrote in 1987:
“The price of increasing wavelength … is that the antenna has to grow in proportion to the wavelength in order to maintain a narrow beam and adequate resolution. The ‘mobile’ Soviet VHF radars are cumbersome, and early-warning radars such as Tall King (P-14) are large fixed structures and provide coverage of only one sector. Despite the size of their antennae, they are not accurate enough to manage a complete engagement.”
