Not to get too technicial, but the title of the post was Dual Band Antenna ???
Not one antenna that does it all.

The only antenna that does more then one or three bands would be the discone antenna...

The Diamond Discone will operate somewhere between 10 meters and 900 MHz.

Any other antenna would require the use of traps or solenoids to make the antenna resonant for that band.

One other antenna - if you had the money and the real estate would be the High Power - Off Center Fed Dipole - which operates practically everywhere between 440 MHz and 160 meters - with the exception of 15 and 30 meters.

http://www.angelfire.com/electronic/hypower/