Yes. Any unused SWM port should be terminated.
With a 75 Ohm Termination cap?
Other than trying to diplex OTA, none that I can see. Seriously, I hope this works for you. I gave up on diplexing some time ago, and have been very happy since.
I'll give it a try, I have one R-22 to put downstairs but I only have a single cable going to it. So I may run separate OTA cables elsewhere and try the diplexer downstairs. If it doesn't work I may just attach a OTA antenna locally and see how it works. I'm not too far from the transmission towers so even though it's downstairs it should be no problem. (Famous last words)
Thanks for all the help.