Consider the circle \( C:x^2+y^2-6x-8y-11=0 \). Let a variable chord \( AB \) of the circle \( C \) subtend a right angle at the origin. If the locus of the foot of the perpendicular drawn from the origin on the chord \( AB \) is the circle \( x^2+y^2-\alpha x-\beta y-\gamma=0 \), then \( \alpha+\beta+2\gamma \) is equal to \( \_\_\_\_\_ \).
