[rmonroe]

As a radio-astronomer: 1. Well, few radio-telescopes have instantaneous bandwidth as wide as a factor of 12 -- they are usually optimal on a narrow region, and therefore hoping that another group with instruments optimized for lower/higher frequencies will do the job 2. Lower frequencies require larger antennas to achieve useful gain. It is more likely that they would go higher than 500 MHz vs lower. Also, dispersion (correctable with a position solve) and scattering (not correctable) eventually become problems with low enough frequencies and long enough distances 3. If we observe at the wrong frequencies, it will most likely not show up. RF filtering and antenna response will ensure that.