Winkle
... that the Royal Air Force's "Winkle" system tracked aircraft by listening for their radar jammers?
... that the <a href="./Royal_Air_Force" id="mwA4Y" rel="mw:WikiLink" title="Royal Air Force">Royal Air Force</a>'s "<b id="mwA4c"><a href="./RX12874" id="mwA4g" rel="mw:WikiLink" title="RX12874">Winkle</a></b>" system tracked aircraft by listening for their <a href="./Radar_jamming_and_deception" id="mwA4k" rel="mw:WikiLink" title="Radar jamming and deception">radar jammers</a>?