Here's the summary I provided back in 2006:
which cited fol. ATI test results submitted to FCC as part of a "How to determine ATSC coverage range" issue:
Alps TDQ Tuner specs claim -84 dBm Sensitivity.
There ARE tuners out there with 2 dB better Sensitivity in non-fading, no multipath conditions.....per the tuner manufacturer SPECS....unfortunately it's next to impossible to find out WHICH boxes use which Tuners and ATSC Decoder Chips [except for CECB's....see my CECB FEATURES link at bottom of this post].
The MOST IMPORTANT performance criteria is how many of the 50 "ON-AIR ENSEMBLES" (aka RF Captures) each ATSC Decoder Chip could successfully process. The ATI Xillion 260H in the DTB-H260F appears to be the same (ATI 5th) Generation chip that could decode 34 out of 50
.....and Samsung "Gemini" prototype (unknown mfr), tested in Aug05 could decode 38 out of 50
CECB's (Coupon Eligible Converter Boxes) were the FIRST and ONLY tuners that had to actually MEET specific specifications per test report submitted to NTIA/FCC (specs derived from ATSC A/74 non-mandatory "Guidelines"...which do NOT always specify pass/fail limits):
Consequently CECB's (using so-called 6th Gen ATSC Chips) ran circles around everything manufactured prior to 2007....and should be representative of nearly any tuner built in 2008 or later due to the very narrow range for additional improvement. See fol. NAB Test Report. [Unfortunately, NO NAMES.]:
[Appendix, pg 4 and 7.]
Sensitivity for ALL CECB boxes was -86 dBm (+/- 1 dB)....nearly ALL the SAME....and about 2 dB better than DTB-H260F.
Of the (only!!!) 7 CECB boxes tested, the worst could decode 37 out of 50
and the best could decode 41 out of 50
Later "7th Gen" (or whatever) ATSC Decoder Chips (usually built into one big Super-Chip) have PROBABLY chipped away at the remaining Ensemble Tests....although perhaps five of them will NEVER be decodeable, since they were off-the-air RF Captures made at the worst-of-the-worst locations during early ATSC On-Air tests in Brazil and the USA.
Prior to 2007, the number of Ensembles that could be decoded was MUCH LESS, showing two groups....TEN that could decode 35 to 38 out of 50
Ensembles with only 1 or 2 Errors....and the other 19 (3rd & 4th Gen) that could only decode a measly 8-15 out of 50
Ensembles (incl. my old Adaptive Antenna capable Sylvania 6900DTE HD-STB with ATI NXT2004 ATSC Decoder):
[See Field Captures, sec 6]
This illustrates that the MOST IMPORTANT advancement was NOT a 1 or 2 dB improvement in Sensitivity....but an improvement in Signal Processing.
The "5th Gen" chips were the first to provide a DOUBLE-LENGTH Equalizer which would center the initial signal in the equalizer, enabling the equalizer to lock onto a delayed multipath signal and wouldn't hickup when an EARLIER flat-fading signal came out of a fade....all earlier Equalizers would initialize the initial signal very close to the beginning of the Equalizer. [A typical problem in urban canyon environment.] See fol. for Zenith specs for their various Generation Chips:
So, what is the bottom line: Samsung DTB-H260F is "5th Gen" and will run circles around earlier Gen boxes...and is ALMOST as good as a 6th (or 7th or 8th) Gen Tuner. Since you probably don't have to deal with the "worst case" multipath conditions found in the worst-of-the-worst Ensemble RF Captures, you probably won't notice which tuners process a few more Ensembles than the other....and would be hard pressed to notice whether your box has 2 dB lower Sensitivity than some Unicorn Tuner that defies identifying which HDTV's or Tuners it might be found in.
It's better to reassess the Antenna and APPROPRIATE choice of Preamp to Maximize the Spurious Free Dynamic Range (Search forum for my "SFDR" posts)....and IF it doesn't reduce Sensitivity due to Overload, a Preamp can "typically" improve the Sensitivity by 10 dB for Mast or Attic mounted Antennas, and ALSO can improve Sensitivity for a simple Indoor Antenna since a Preamp should provide a better SWR match than a Super-Het Tuner (with a tuned input filter)....and also reduces the Sensitivity Loss due to the Tuner's internal Noise Figure.Edited by holl_ands - 12/20/13 at 12:40pm