I just got a Tablo 4-tuner model, and have the same signal strength issue that others have reported.
I've put separate, identical antennas (Mohu Leaf) on the TV and Tablo. My thought was to watch live TV on the Samsung, and only use the Tablo for time-shifting.
I'm not happy with picture quality for any of the "live" streaming services I have tried SlingTV, Playstation Vue, and Hulu Live TV so far - of those Playstation Vue has the best picture quality. I've yet to test Direct TV Now. I cannot live with the UI of either Playstation Vue or Hulu Live, though. Frankly, I would forget the "cable channels" altogether and save $40/mo if it weren't for CNN. Maybe it's just time to admit that CNN doesn't really provide the best news - just endless repeats whenever something "big" happens... I will miss you, Anthony Bordain!
Anyway, my Samsung TV receives all of the same channels reliably. The Tablo tears and has gaps/scrambled sound on quite a few channels.
I suppose it makes sense that any multi-tuner model is going to have some issues with signal strength. But they SHOULD have an internal amp (do they?) if they are going to split the signal 4 ways. That is going to incur some noise, though. A purist would call for 4 separate antenna inputs!
I'm guessing I need a 6db bump in signal strength.
I cannot put anything outdoors. I am in a highrise condo (ok, "high rise" for 1927!), near downtown San Diego. I threw the Mohu Leaf for the TV under the sofa, near a window. It doesn't seem to matter where I put it. I see neighbors with them in the windows, I hate that!
For the Tablo, I've stuck the antenna high in my office behind some shelving where it can be hidden. The Tablo is in my server rack. It's a few feet from a window.
The building is steel/reinforced concrete construction, but the outside walls are i think pretty transparent to RF. They are terra cotta brick (thin wall hollow brick), a somewhat unique building material used in S. California for the first part of the 20th century. 3rd floor on a hill facing S, which is where most of the transmitters here are. (Or in most cases at least have relays in that direction.)
Suggestions? Maybe best to avoid an active antenna, and just get a larger non-amped flat antenna?