i agree. think about it, there are only what 12/16 something like that gps satellites circling the earth total. The earth is round. how many can possibly be in the line of sight at any one time? It really cant be more than a few, certainly not 10, then the other side of the globe would have little signal. the satellites are orbiting in a pattern that you always have at least 2 or 3 there for a lock at any time.
Its pretty simple if you really think about orbits around a sphere that everyone has to be covered by at least 2 or 3 at all times. the time of day may give you more locks than normal at certain times due to orbits coinciding, but you certainly arent losing the ability to get any lock during any part of the day. Its simply the flaky gps implementation we have currently on the Touch, or the weather. Clouds and bad weather contribute to impeding the signal too.
and as mentioned above there is that tower/a-gps function which is why its on the phones. It help when you only have 3 locks lets say. It will use gps PLUS tower triangulation making it as close to accurate as possible. That's why a-gps even exists or else there''d be no need for it if there was always good gps signal from many satellites. its there for those poor gps situations.
http://trl.trimble.com/dscgi/ds.py/G...upPlanning.exe here is a desktop program that will tell you the ideal gps times for your area, just for reference and to play with