You can compare antenna gain figures at ,
http://www.antennacraft.net compare the the , HD1850 , HD1800 , MXU59 , MXU47. And at
http://www.winegarddirect.com compare the HD8200P and the HD7698P and the HD9095P and the HD9075P gain figures. And you can compare all the other antennas at these two manufactures.