Comparison of San Diego observations (March 1992) with international reference ionosphere predictions

Abstract

During the month of March 1992, the new ionosonde at NRaD in San Diego, CA U.S.A., was used to obtain ionograms at five minute intervals. The new ionosonde is similar to the two channel HF sounder developed at NOAA in Boulder, CO U.S.A. in the late 1970s /i/, however, the NRaD machine is the first fully four channel version of that machine. The four channel architecture permits faster and simpler operation since antenna multiplexing used for the two channel machine is no longer required.