How much does Video Modulator quality vary?

["Chuck" <JGScott987@xxxxxxxxx>]

I have an inexpensive modulator that I use to inject video onto channel
94, which is then distributed throughout the house. I paid about $40
for this at Radio Shack on closeout- I notice that they don't carry the
model any more.

The picture is reasonably good, but not as sharp as regular analog
cable, and not nearly as sharp as s-video straight to the TV. I know
you give something up by modulating the signal, but shouldn't it look
as good as the rest of the cable channels?

Should I get a measureably better picture if I step up to a higher
quality modulator?

Thanks for your input.