dvd dummy question

I finally bought an inexpensive dvd player/recorder deck. It worked
fine with my Sony, which recently died. Also, works great with my
ancient 13" Amiga 1084 (what doesn't?). So, I dragged out an older,
but little used, Wards tv that I had in storage. This tv works/looks
great, but is pre-dvd. It has a vcr mode, but no dvd mode. It also
has no separate audio/video connections. So, all I have is the RF
cable connection from dvd deck to tv. Well, it doesn't work. The
tv's vcr mode apparently does not recognized dvd signals, even if my
cable tv signal goes through the dvd deck just fine. Looking at the
manual, it shows a separate "Stereo Audio/Video RF Modulator
(commercially available)" inline between the dvd deck and the tv.

So, the question is: Do I need to buy a modulator or do better dvd
decks come with this modulator built in? If so, I'll just take this
one back and upgrade. TIA for any advice.

nb