HDMI RF Modulator VHF Coaxial Converter HD 1080P Input Coax Output Adapter w/Remote for Laptop PC PS4 PS5 VCR DVR Chromecast Blu-ray Roku Fire Stick Set-top Cable Box Digital Video to Analog NTSC TV

If your source is HDMI, I would recommend trying a modulator that has controls for adjusting the vertical and horizontal size of the image, because that will allow you to get the aspect ratio to match the source. You can either zoom in on a widescreen 16:9 video to crop out the sides for a fullscreen 4:3 picture, or you can shrink the height to letterbox the video and make it properly display the entire widescreen image.Here is an example of a modulator like that:https://www.amazon.com/dp/B0FNJ16M41

[HDMI to Rf]You need one of these. (https://www.amazon.com/dp/B0FNJ16M41?ref_=cm_sw_r_cso_cp_apan_dp_ss_3863CXD7C0PJ7CMKTSY5)