Sonny & Cher began in the mid-1960's.
Pip-squeak was a simple radio navigation system used by the British Royal Air Force during the early part of World War II .. radio navigation. radio navigation. Royal Air Force. Royal Air Force. World War II. World War II. Pip-squeak used an aircraft 's voice radio set to periodically send out a 1 kHz tone which was picked up by ground-based high-frequency direction finding -LRB- HFDF , `` huff-duff '' -RRB- receivers .. high-frequency direction finding. high-frequency direction finding. Using three HFDF measurements , observers could determine the location of friendly aircraft using triangulation .. triangulation. triangulation. Pip-squeak was used by fighter aircraft during the Battle of Britain as part of the Dowding system , where it provided the primary means of locating friendly forces , and indirectly providing identification friend or foe -LRB- IFF -RRB- .. fighter aircraft. fighter aircraft. Battle of Britain. Battle of Britain. Dowding system. Dowding system. identification friend or foe. identification friend or foe. At the time , radar systems were sited on the shore and did not provide coverage over the inland areas , so IFF systems that produced unique radar images were not always useful for directing interceptions .. radar. radar. Pip-squeak was added to provide coverage in these areas .. As more radar stations were added and over-land areas became widely covered , pip-squeak was replaced by IFF systems of increasing sophistication .. radar. radar. Pip-squeak gets its name from a contemporary comic strip , Pip , Squeak and Wilfred .. comic strip. comic strip. It was first implemented in the TR .9 D radio .. The system was also used by the USAAF , where the equipment was known as RC-96A .. USAAF. USAAF