BABS gave range as well as left/right indications and I don't recall any markers. QGH down to 1500ft and at 5 miles start downhill at what you hoped would give 300ft/mile, observer on the 'Rumble' seat and plotter calling 'Dots 1, Steady, Dashes 1, Steady' you hoped, plus ranges - effectively an in-house ACR7. The required landing rate for the stream was one every 3 minutes, and since take-offs had been at 1 min or even occasionally 30 sec apart, with 3 x 16 U/E squadrons on exercises there was sometimes a lot of time to lose in the 'Trombone' on return. Primitive though the system was, it did work.