To study the carrier frequency effects on path loss, measurements have been conducted at four discrete frequencies in the range 460-5100 MHz. The transmitter was placed on the roof of a 36 meters tall building and the receive antennas were placed on the roof of a van. Both urban and suburban areas were included in the measurement campaign. The results show that there is a frequency dependency, in addition to the well known free-space dependency 20 log 10 (f), in most of the areas included in the measurements. In non line of sight conditions, the excess path loss is clearly larger at the higher frequencies than at the lower. A model capturing these effects is presented.