of unknown origin; (2) The high-redshift (z) universe, including distant black-hole-powered radio galaxies and clusters—tools for understanding proto-galaxy collapse in the early Universe and the cosmological evolution of Dark Matter and Dark Energy, respectively—and path-finding studies of the Dark Ages at z > 30 (í < 50 MHz), before stars turned on or galaxies formed; and (3) Acceleration, propagation, and turbulence in the interstellar medium, including the space distribution of galactic cosmic rays and supernova remnants together with scattering- and absorption-based probes of the magnetized interstellar plasma.

Meteor scatter and sporadic E can have path loss as low 160 dB (for distances in the 800-2000 km range) at 30-50 MHz so that an EIRP of about –30 dBW will be at the interference (approx. –190 dBW sensitivity of the LWA) threshold levels of the LWA. If the radars radiate +20 dBW EIRP (100 watts) out to sea they will need to be sure their antenna backlobe is down by 50 dB to avoid interfering with the LWA in New Mexico.

Recommendation: Unwanted emissions due to new radar allocations the 3-50 MHz range should be low enough to meet the levels of Recommendation ITU-R RA.769 in the Radio Astronomy Service bands at 13.36-13.41, 25.56-25.67 and 37.50-38.25 MHz.



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