Talk:Water hole (radio)
|WikiProject Physics||(Rated Stub-class, Low-importance)|
I've always seen the Water Hole defined as 1420 MHz to 1640 MHz, but I don't fully know why the upper bound is that since there doesn't seem to be a notable hydroxyl line at 1640 MHz. The strongest hydroxyl lines are (as far as I know, which is admitedly limited) at 1665 MHz and 1667 MHz. One official-seeming site () shows other hydroxyl lines at 1612 MHz and 1720 MHz, but neither seem to explain where the 1640 number originated. One-dimensional Tangent (Talk) 18:23, 27 August 2005 (UTC)
could it be that there is a lot more noise upwards of 1640 and much less below 1640?
Just a thought. I understood that the hole was the relatively quiet space between the noise from water and the noise from a hydroxyl molecule. Maybe only part of the space between those two points is actualy quiet.