#1: The steerable s-band antenna was controlled by a knob, it could have been switched. (not saying this happened, but it happened before). Also it is possible the automatic control "lost it". There had been more problems with this antenna.
#2: Not necessarily, any resistance would have done it. Also if you look at the movement and the abrupt stop of it on one axe this is can't be explained from gravity.
#1 - Your explanation must explain the others, else it's not a "legitimate explanation" -- for example, they simply added "STATIC" rather than cutting the signal. And never mentioned this issue.... only said "My Antenna is OK" -- none of this makes sense, and therefore your #1 explanation fails. Also, when it's "tracking earth" in a rotation like this -- it would also make no sense to ever "use the knob", to do something that is far better done automatically.... as WAS BEING DONE, when the guide cable broke.
#2: Learn more about this physics. For a hinge joint, there are extremes of rotation... if you hit the extreme, then you will BOUNCE off of this extreme, and reverse directions. If you are oscillating to the opposite direction before hitting the extreme.... this then is the real problem. In no gravity, it would ALWAYS go to the "Extreme" then bounce off... But with gravity.. the gravity pulls it back, and so it reverses direction BEFORE hitting the extreme.
For example, if the extreme is 20 degrees... the first few oscillations hit this 20 degrees, but the 3rd/4th one did not, the 5th, 6th, 7th ones got less and less -- yet continued to reverse directions without hitting that 20 degree extreme.
Also -- pendulums in gravity last longer, than does "bounce-based oscillations" because more energy is lost in bouncing.
So with no gravity -- every swing would go to the extreme... bounced, then reverse directions... until friction and elastic-bounce-loss absorbed all of the kinetic energy.
In a Pendulum, you do NOT have the loss from "poorly elastic bounces" -- and so it lasts longer..
Just spelling it out -- as it seemed you didn't have a clear grasp of pendulum science, versus the "no gravity oscillations on a constrained hinge joint".
The "reducing amplitude pendulum motion" is difficult to contend with for Apollogists.