Latest Ionogram. Digisonde Scaled Data. Digisonde Scaled Data The HAARP Digisonde includes the ARTIST-4 software component which performs autoscaling of ionograms. Autoscaling is the process of determining the characteristic parameters of an ionogram, such as foF2 (the F2 layer critical frequency), using software to interpret the reflection layers in the ionogram. A description of the available scaled parameters can be found here . One or more parameters can be selected for display by holding the key while selecting from the list. HAARP VHF Riometer. HAARP VHF Riometer The chart below is a plot of the readings taken using the HAARP VHF Riometer .
This instrument is a sensitive receiver tuned to a frequency of 30 MHz. The antenna is an array of 4 element "yagi" type elements pointed directly upward to listen to the background or galactic noise. This noise varies from one hour to the next as the Earth rotates and, in the absence of ionospheric absorption, is a constant, repeatable function of Local Siderial Time.