Notes on RF scale testing of tower mounted antennas for cellular communication

Scale model towers with associated antenna installations provide an efficient and fast means to test current and future 1800 MHz mobile communication base station installations prior to site, antenna type or mounting scheme selection. Repeatability better than 1 dB is readily achieved if the scale reduction is between 1:5-1:15. Many measurements are possible with a very short anechoic test range, just fulfilling the far field requirement. Typical findings include the possibility to effectively reduce interference minima caused by adjacent vertical structures by simply positioning a thin absorptive sheet to the optimum location. Improvements of the order of 20 to 30 dB have been measured.