Actually my dipole is called a shorty 80/40. It is only 70 feet long made by Maple Leaf Communications. It is made for just 80 and 40 without a tuner, but I have had very good luck with it on 20 with a tuner.How long is the dipole from end to end? If it is not very long I guarantee you only think it works great on 80m. The OP is talking about just a dipole for CB.
I have a doublet installed which a lot of people call a dipole but since it is non-resonant and fed with ladder line it is called a doublet. It is about 120 feet end to end and is in an inverted V fashion with the apex at 65 feet. It does work fairly well even on 80m but I can't wait to get my yagis up in the summer.