I have only seen one of those "Flying Saucers" come off and .. Well it took a lot more than going down the highway (The story at end of this post)
I would not replace that type of antenna with a like type. I'd go with a Winegard Sensar IV.. There is a reason for this. Several in fact.
First the Sensar line when cranked down is very "Flat" not much chance of anythign snagging it and ripping it off (See story) 2nd it is the BEST rv TV antenna, that flying saucer.. Well likely the WORST RV Tv antenna. Bar none in both cases.
The story
Brand new class C with one of those parked beside me. First time in the RV, I had to show the owner which keys fit which locks on the door (Same locks I have). Sticker still in the window they had flown in and the dealer picked 'em up at the airport and handed them the keys to their new "house".
They went to dinner down the road. the sign on the parking structure said the ceiling was high enough for the RIG but the Pipe.. Hangs LOWER than the number painted on it.. Went right in UNDER that saucer. Ripped it clean off, flew up and landed on the vent cover for the bathroom vent. SMASH.
And the sticker was still in the window.