thanks for the input alex, so thats how bigger aperture leads to less site error. Nicely explained. But I believe there's also another phenomenon here acting to reduce the site error called "Capture effect". This refers to the capability of aircraft receiver to demodulate only the strongest of the variable phase VHF signals from doppler VOR, ignoring the reflected but weaker variable phase signals. As opposed to the CVOR wherein the average of the direct and the reflected weaker signal is taken into account to derive a wrongful "average" bearing. Would like your comments on this.