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Old 26-Jul-2010, 9:32 PM   #2
Join Date: Dec 2009
Posts: 632
It is possible for different receivers to have better or worse sensitivity ratings.

The two tuner specs that matter the most (if they are published at all) are its sensitivity and its noise figure. These will determine how well it deals with weak incoming signals. Unfortunately, tuner specs are rarely, if ever, published for your average consumer TV.

Did you add a splitter to test the TV? If you introduced a splitter that wasn't there before, the splitter itself will cause the signal levels to drop a bit (since the power is now being split to multiple paths). Also, some cables are more lossy than others (e.g., RG59 vs. RG6). In order to have an apples-to-apples comparison, you would need to make sure that each device is being tested against the exact same antenna feed (same cable, going back and forth between receivers) at around the same time of day.

In general, based on hands-on experience with several converter boxes and TV sets, I'd say that the converter boxes do tend to be slightly better than the built-in tuners of most TV sets, but the difference is usually small (maybe just a couple of dB). This should only affect weaker stations that are borderline receivable, so you should not observe that much difference on strong signals.

Another possible explanation for the differences you observed is multipath. Maybe your signals are strong enough, but the antenna is picking up signal reflections from somewhere (off of other buildings, hills, etc.). Some receiver chip-sets do a better job of coping with multipath than others using the "equalizer" logic in their design. Most newer chip-sets (built in the last 1-2 years) do a much better job than the ones from a few years ago.

Based on the information available, it's hard to say whether the problem was related to tuner sensitivity or its equalizer performance. If the problem is only related to the signal being too weak, this can probably be fixed by adding a pre-amp to your antenna setup (if you don't already have one).

If the problem is related to equalizer performance, then you might get very different results with a different make/model of TV that uses a different chip-set.

Generally speaking, there should not be anything seriously deficient in the design of tuners that are built-in to TV set. Maybe you got a lemon, maybe the particular make/model of TV had a bad (perhaps older) tuner design, or maybe the TV generates too much of its own interference (TV's have far more electronics internally than most converter boxes).

If you converter box and your friend's tuner dongle are able to pick up lots of channels cleanly, then I wouldn't expect that much of a difference using a TV's built-in tuner. If your antenna setup includes a pre-amp, I would expect almost no difference at all between the devices.
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