The DTA doesnt need a much of a signal..it can handle a lower signal and still be OK comparatively.
The cable, unless its a really old one.. etc.. if you are using the same one as say the other room, it should be fine.
ONLY thing i could say, is for whatever reason, the signal to that outlet, is poorer.
Having a tech out, to check signal, etc WILL NOT cost you anything, as long as there was nothing like self put in splitters (which you say there are none), etc that cuased it. I have had probably 20-30 tech visits over the years, and never once been charged.
update: I left the box plugged with the LED spinning after tightening all coax connections. Upon going to bed, I noticed no spinning led. To my surprise, it turned on with a stable signal. Since its now in the kiddie room, I listed the previous recordings on it and deleted any inappropriate content and turned it off with the remote.
I called my children into the room to give them the grilling of how to keep the room tidy now that it is working and to my surprise.....no signal again.
Tech should arrive this afternoon and I'll update for anyone reading this.
The technician arrived on time and was very professional and worked well.
The ends of the coax from that arm of my circuit were comprised of those twist on ends....as opposed to compression fittings.
He cut them off and replaced them with compression fittings and presto...all good now. He also re-used the old cable I was using in the room after the wall plate by clipping off the ends and replacing them with compression fittings as well.
Since the initiall install was done by a Rogers Technician 3 years ago when the house was build....Im not sure why they used twist on on some legs and compression on others but......its all good now.