Maqam World says Maqam Bayati "starts with a Bayati tetrachord on the first note, and a Nahawand tetrachord on the 4th note (the dominant). The secondary ajnas are the Ajam trichord on the 3rd note, and another Ajam trichord on the 6th note. These are often used in modulation." Pretty technical, but the best way to learn to hear this Arabic "scale" is to listen to a master improvise upon it. That is what Mustafa does in this video. It's a real joy to watch and hear him as he works his artistry. Thanks again, Mustafa!