There's a very good possibility that the tuners in the DVR+ can be easily overloaded. It's been noted that they can be quite fussy and seem to have a limited threshold with strong signals.If you go back about 3500 posts , to when AVSF users first started receiving product, you'll find glowing reviews of the tuners.
When I saw there was another 3500 posts to get to here, I decided to skip to the end.
Unfortunately, I'm in a marginal location. It shouldn't be. Save a few close-by trees (which may be the problem--but that doesn't account for wintertime): I'm at an elevation that looks "down" on all the towers, which are in a 12° arc of one another, about 14-16 miles away. Nonetheless: Reception can be problematical--particularly if it's storming, the wind is blowing or planes are flying overhead (we have an airport about one mile to the north, as the crow flies).
With the Winegard FlatWave Amped antenna I'm testing, things are much better, it seems. But the new (eight years ago) Winegard HD7078P VHF/UHF antenna on the roof has never done well. (Belden RG-6, all the way, weather-proof compression connectors crimped with a DataShark. [I used to be a "radio guy."])
Unfortunately: Short of putting up a tower: I've no other outside antenna options. And I'm not certain that would help. The symptoms kind of suggest reflections are the problem (the grade continues rising by an additional 400' or so [?] behind the antenna), which might explain why the inside antenna is actually working better than the outside one.
That's what I'll have to do.
If the tuner works well on receipt, can I expect it will continue to do so?
That may explain why an antenna such as the Winegard may actually produce better results (with weaker signal).
You also need to consider the deterioration of your roof antenna and the fact that coax cable will also deteriorate over time.