The left antenna (a horizontal hoop) minimizes the amplitude given that the remaining hand is moved closer to it, although the proper antenna (a vertical pole) raises the pitch as the proper hand is moved in the direction of it. For the last fifty seven yrs, the company Bob Moog https://manualliftingequipment93815.timeblog.net/74107593/the-fact-about-pallet-gates-uk-that-no-one-is-suggesting