Can that antenna be used as a base/fixed antenna on a mast? Yes it can, if you make an addition or two to it. Very simply, you have to supply the part that the antenna expects to see when used on a vehicle, the other half of it, the counterpoise, groundplane.
(I hate that word, 'groundplane', it's misused a lot. But in this case, it's exactly what's needed.)
Like with most multiband antennas that require a groundplane, if you furnish a groundplane sized for the lowest band of use, the higher bands just use what they need and don't worry about the 'extra'. So, if you plan to use 10 meters, the lowest band for that 'Comet UHV-4', then that's the size of radial(s) I'd put under the antenna. Not gonna use 10, just down to 6 meters? Fine, do 6 meter radial(s) instead. Or just 2 meters isw that's all you want to use.
So what size should these radials be? Good question, I can't answer that cuz I don't have one. They should be a minimum of the same length as the antenna, plus a little more probably. Lot's of 'skootch' room there, use whatever works for you.
How well will it work? Can't say for sure, but it ought to work as well as if it were on a vehicle. Probably a bit better cuz it's higher (don't expect miracles
That antenna has to be one of the best you could have! Why? Cuz it was 'free', naturally! I tend toward 'Comet' VHF/UHF
antennas if I can, I've had good experience with them on mobiles. That certainly doesn't mean very much, I haven't tried them all, so take it for what it's worth. Also found one or two that were a PITA, mainly because they were a bit 'more' antenna than I thought they were (hit a tree limb, knocks down tree limb, that sort of thing, weird huh?).