I've recently got into IPTV and got myself a nice IPTV service that provides me a .m3u8 or .m3u playlist with all the channels. As recommended I then use an app called SS IPTV on my LG WebOS smart tv.
The app works just fine and it's very robust, but I prefer to have my channels operate as the regular antenna channels because I find it more comfortable if I have them integrated within the default TV UI rather then in a separate, 3rd party app.
Now I have a small Ubuntu server under my TV that I use for Emby and I'm looking for a way to perhaps add some PVR card/box that is capable of output and connect it to my TV with a coax cable directly into the antenna jack with the goal being that the channels will appear as standard antenna channels (look at it as closed circuit cable TV).
So far I wasn't able to find anything like this but I believe I just use the wrong terminology when searching. Is this is possible and easily achievable with off the shelve card/box/stb etc. and with some standard software that is available for Ubuntu Linux or even better is there some sort of Set Top Box that I can hook the IPTV playlist to and then has a coax output that I can hook to my TV?
Yes this can be done. But there are a few things you should know.
Old school coax is limited in bandwidth and therefore in resolution. Don't expect 4K or UHD to be carried over it in analog signals. Also the amount of analog signals carried is limited, somewhere around 30 to 35 channels , less if the resolution rises.
And last but not least, you are talking about a pro solution, it is not common to have someone at home start a closed circuit cable TV solution. With a pro solution comes a pro price.
The terms you are looking for are TV headend; Ip to DVB-C converter ;
In the past Hirschman Multimedia produced equipment for this, but I can't find anything on their website now.
Now to help you more, I would go for a solution based on a Android TV based product and look for an app that incorporates the live channel concept.