HAZARDS AND FUTURE IMPROVEMENTS TO HI SURVEYS

Most radio astronomical observations are affected to some degree by ma n-made and natural interference. There are a few avoidance techniques that can reduce the impact of interference an the survey, but we must make quite significant advances in the understanding of our antennas a nd receivers and the interference itself before a substantial improvem ent can be expected. A major increase in the efficiency of future surv eys will likely come from phased-array feeds, which have the potential for much closer beam spacings, greater antenna efficiency, and wider fields of view than current independent-feed arrays.