OK, I've seen similar questions, but not this one. My new DVD recorder has a coaxial output as well as scart, but will not connect to my TV (which doesn't have scart). Is it possible that the Co-ax out is simply a loop through for the recorder and the only actual output from the DVD writer is via Scart or RCAs. I can't connect it to the other telly because that's old too and only has 1 scart input which is already used.
DVD recorders do not tend to have an RF modulator (as with a VCR) - as you say the co-ax out is just a loop-thru for the normal signal - not including the output from the DVD.
You could use a specialised RF-modulator or a "wireless sender" for the first TV or alternatively a SCART "splitter/adaptor" for the second TV.