I was in conversation w. a friend, and he offered a very logical explanation for my misled expectation: the TV picture is made up of only 560 pixels across, as compare to the PC's screen of 1920 pixels across. In other words, the TV picture is being stretched 4 times as large on a PC screen (especially when viewed in "full screen" mode on a 24" monitor). It is no wander that the TV picture would be seen as very grainy.

After this explanation, my guess is to burn the recorded TV program on a DVD, then play it in a DVD player that's connected to a regular TV, and see how the picture would look like on a TV screen.