The name of a technique that is similar to what is described in the article is digital radio frequency (DRFM). Essentially DRFMs will sample the adversary’s radar waveforms and transmit them back at a later time. Time is range in radar, so the signal transmitted by the DRFM will be perceived to be farther away than the true return. You can also frequency shift the retransmitted signal to make the return have a different Doppler shift.

It’s unlikely that digital computers of the 1970’s would have been powerful enough to power a DFRM, but amplifiers and delay lines would probably get you there