Yeah, ATV say "anyone who knows about aerials knows Tri Booms are not made to work, they`re made to sell"My feeling is that those 'three boomers' are more spin than performance and mainly designed to look impressive.
Is tricky to recommend something specific but one of the 'wideband' jobs from here would be my choice:
ATV aerial shop
DY14WB, Yagi18k and Grid are fairly high gain. DM Log periodic is less powerful. If size is a problem the Grid might be worth a punt, though if it has to face along a wall you'd need a fairly long bracket.