First bistatic oblique-incidence ionograms between digital ionosondes

Identical digital ionosondes (dynasondes) at Brighton Colorado and at White Sands Missile Range, New Mexico, 864 km distant, were synchronized for bistatic sounding in multifrequency and fixed frequency recording patterns. Three propagation modes are observed, identified, and reconciled with standard propagation theory; these include one‐hop propagation by sporadic E (Es) and the F region and two‐hop (F ‐ Es). Echo phase measurements at the four spaced antennas of the dynasonde receiving array permit echolocation calculations that are in good agreement with the path mid point, although effects of ionosopheric tilts and time variations are evident. These results encourage the concept of a global real time ionospheric monitoring network consisting of about 90 instruments that perform vertically incident and coordinated bistatic soundings, to yield a total of about 320 measurement ‘locations.’