A straight line cuts off the intercepts \( OA = a \) and \( OB = b \) on the positive directions of x-axis and y-axis respectively. If the perpendicular from origin \( O \) to this makes an angle of \( \frac{\pi}{6} \) with positive direction of y-axis and the area of \( \triangle OAB \) is \( \frac{98}{3}\sqrt{3} \), then \( a^{2}-b^{2} \) is equal to:
