I used Deborah Norville Everyday worsted, holding two strands throughout, with size 11 needles (USA).
Cast on 28 stitches, any way you prefer. I used the long tail method.
Row 1: knit
Row 2: purl
Row 3: knit 2, *6-st left cable; repeat to end, knit 2
Row 4: purl
Row 5: knit
Row 6: purl
Row 7: knit 8, 6-st right cable, knit 6, 6-st right cable, knit 2
Row 8: purl
Repeat rows 1-8 until desired length. I repeated the pattern 11 times, and my cowl is about 28 inches.
6-st left cable: sl 3 sts to cable needle, hold to front of work, knit 3, knit 3 from cable needle
6-st right cable: sl 3 sts to cable needle, hold to back of work, knit 3, knit 3 from cable needle