I have some kind of Hauppauge TV card in one of my PCI slots. I believe it has WinTV and PCI in the name. I use Red Hat 9 Linux and found that a program called xawtv was already installed on my computer. It is one of those programs that are not in the menu anywhere but can be started from the command line. All I had to do to start it was type xawtv (or xawtv &).
I will assume that perhaps you already have xawtv or something similar installed. If not you will need to figure out how to install it from an RMP and get it working. That part was not necessary for me and I am not familiar with how to do that. On my computer xawtv was already installed but not configured correctly.
The first time I ran xawtv I found myself looking at a blank screen full of static. No menu was visible either. Fortunately, chapter 8 of the Red Hat Linux 8 Bible listed the keboard shortcuts for operating xawtv. I pressed O for the settings window. If nothing happens look around for a window that is almost hidden by the taskbar. So anyway, once the options window appears look to see what is listed for "TV norm". The default is PAL. In the US we have NTSC TV signals not PAL signals. So I changed it to NTSC.
Next, I changed the frequency table to us-bcast. I do not have cable TV but for people that do there is a different choice for that. At this point it should be possible to use the up arrow and down arrow on the keyboard to change channels. For each channel that could be received I pressed E to bring up the channel editor and added that channel to my list of channels.
When I ran the program for the first few times the program reverted back to the PAL settting once or twice before I somehow got the changes to stick. Even when it reverted back to PAL my list of channels remained there with their correct NTSC settings.
There is another program that is similar to xawtv that some people use instead. I can not remember what it is called. I enjoy watching the televison news in one corner of my screen while working on something else in another window. I have seen some older more complicated instructions posted on the internet for getting the Happauge TV card to work. If I recall correctly it required me to identify the chipset on the card and make sure that the correct modeules were loaded. None of that was necessary on my computer. The only problem was that xawtv was configured for European TV channels by default.