i can see what hi def is saying about wavelength vs height,
most people over here dont have their cb antenna up over one wavelength to feedpoint, they used to years ago, mine was up at two wavelengths in an open field but times have changed, neighburs attitudes have changed the local councils attitude has changed,
cebik had something to say on the issue of height above ground vs which lobe is the dominant lobe but did not commit,
he said it deserves more detailed investigation..
my feeling is that depending on the electrical length of the mast and the electrical length of the outside shield of the coax you will have lower or higher commonmode impedance, the worst case scenario been a mast or feedline that is electrically multiples of halfwaves between feedpoint and ground, best case been where that length is odd 1/4wave multiples,
i agree with hi def, unless your sleeve balun is made correctly with a very large sleeve to coax diameter ratio ( fat pipe thin coax ) and using low loss dielectric covering on the coax they wont have a high choking impedance at all, rg8 running through a 1" pipe is near useless.
