Yah, I wrote that article. My B-T modulator has run happily 24/7 for several years since I replaced its power-supply electrolytics. The article also includes the chart for setting the channel DIP switches on that model.
I also made a tuned antenna for transmitting throughout the house, although if I’m receiving in the same room, some TVs don’t need any antenna at all.
Once you have the modulator running, you can plug in any source with a video and audio output. At various times, I use a DVD player, cable TV box, iPhone with A/V adapter, whatever.
Since you already own one, it’s worth spending a few bucks to get it working.
Regards,
Phil Nelson
Phil’s Old Radios
https://antiqueradiorg/index.html