These ionospheric data consist of scaling notes, equipment usage logs, and ionospheric values in the form of daily work sheets, F-Plots, tabulations, and booklets. The station notes list the equipment used, power settings, frequencies used, equipment problems, and other information about the equipment. The daily work sheets, commonly referred to an 7E's, are the paper forms used for recording the scaled values values of the ionospheric parameters. Tabulations and booklets contain the published values by ionospheric parameter. If publication errors arise or are suspected, the daily work sheets are usually consulted, if they are available.These data are available from the NOAA National Centers for Environmental Information (formerly National Geophysical Data Center) as electrostatic copies and some as imaged files. Most of the data are in the form of daily work sheets, tabulations, and booklets. The booklets and tabulations have each ionospheric parameter listed on one or two pages, depending upon the format. The daily work sheets have one day (24 hours) of scaled ionospheric parameters on each sheet.