Dielectric measurements have been carried out on (AgI)(x)(AgPO3)(1-x) glasses, with x=0, 0.2 and 0.5, from 10 Hz up to the microwave frequency region using a broadband dielectric technique up to 500 MHz and waveguide equipments up to 40 GHz,. A wide part of the dispersive region in the real conductivity is then available in the case of undoped silver metaphosphate glass, revealing that even at room temperature, a nearly constant loss behaviour is approached. At higher frequencies, a power law dependence of conductivity on frequency is observed, with exponent q>1, in the glasses with lower dc conductivity, but a maximum slope of only 2/3 is attained for the heavily doped (AgI)(0.5)(AgPO3)(0.5) glass. Further broadband investigations at lower temperatures are expected to give a clearer picture of conductivity dispersion features and of their eventual dependence on the structural modifications induced by the doping with AgI.