ATSC Converter Boxes (Non-HD, Non-Recording)

[recneps77]

Good to know, thanks!

[holl_ands]

NAB just released a report re Antennas Direct Prototype Smart Antenna,
http://www.nabfastroad.org/
A number of (intermittent?) interface glitches were identified...and perhaps
will eventually be fixed in existing/new boxes.....
I was disappointed the report glossed over the VHF aspect of the problem....

===================================
The above link also revealed NAB/MSTV's Report re CECB (converter box) performance
and User Guides for 20 CECBs....Note the interior photos in the Summary Report.

I'm surprised this report has remained pretty much unknown since Dec 2008.
Each manuf/model is clearly identified so we can see exactly how each performed.
Parameters tested include: Sensitivity, single signal Overload, Analog Pass Thru
insertion loss (for an attached analog TV), scan time (with & w/o Smart Antenna),
and Signal Quality Indicator characteristics (including correlation to bit error rate,
SNR and signal levels).

NTIA technical requirements tests included Adjacent/Taboo Channel Interference,
White Noise SNR performance (15.0 dB +/- 0.25 dB), static multipath echo and
ATSC A/74 defined RF Captures of particularly difficult multipath conditions experienced
in earlier field ATSC tests....where there was the MOST difference in performance....
but very little correlation to either sensitivity or static multipath echo performance.

Very little variation in Sensitivity (-86 dBm +/- 1 dB)....or 3 dB better than NTIA requirement.
Only one of the APT models experienced a significant insertion loss (about 3 dB) for
an attached Analog TV....but did NOT experience a similar loss for the DTV signal.

[bentoronto]

OK.... I'm more confused than ever.

For 16 months, we've been using a fringe yagi roof antenna and getting Buffalo PBS (50 miles from Toronto) with a 2002 Zenith HD-SAT520. But some nights, no reception and things go fuzzy when airplanes are overhead. The PBS tower angle is within 2 degrees of the CN Tower.

Seemed unanimous among those who had an opinion that a current Generation 5 (or 6) chip set converter would be a major improvement and might get PBS all the time.

So, last night I bought an Artec T3AP-LL, which is from the present crop of converters and a reasonable choice if not the fanciest unit out there.

Guess what? The Artec gets about 10 stations while the Zenith gets about twice that number. At this point, I am not sure if the Artec is defective or if the Zenith from 2002 has a hotter front end.

I compared them quite precisely side-by-side using a splitter and simultaneous yellow-plug video signal inputs to the TV. The Zenith has both HD and SD tuners, HMDI and all other outputs, and works like a charm. Saw a Daytec 32 inch HDTV for cheap today; not a lot of sense buying an expensive set-top converter if HDTVs are getting so affordable.

Of course, I know I can make the Zenith better by enhancing the antenna system in various ways (no advice wanted for that, at the moment) - but I'd like some explanation for my Artec fiasco.

Question: Do you suppose this unit is defective or did the folks who made the Zenith long ago install a hotter front end? The Artec does not appear to be damaged but why does it get so few stations or get some of the same stations with an obviously weaker picture?

[Laird]

does any of this stuff work in Alberta.Most posts seem to be from the East.(no offense meant)

[recneps77]

They will work anywhere in Canada and the US - whether you have digital stations or not is another story (check the status threads for the area you want)
Regardless, though, I believe all these boxes have analog pass-through, so at the very least you can still watch analog and if there are digital stations, those as well.
(pointless to get if there are zero stations around you, though)

[tenstu]

Hi Laird,

As recneps77 mentioned, the gear works anywhere.

However, if you were wondering if Alberta has OTA Television available, I suggest you look through the Reception Results Thread and look for your area (ie Edmonton, Calgary)

http://www.digitalhome.ca/forum/forumdisplay.php?f=129

Stu

[holl_ands]

Not all Converter Boxes have APT (Analog Pass Through). Check the list:
http://www.avsforum.com/avs-vb/showt...php?p=14872530
[Yeah, I know I haven't updated it for a long time...but it hasn't changed much....]

Also Wiki:
http://en.wikipedia.org/wiki/Comparison_of_CECB_units

[stampeder]

Originally Posted by bentoronto

The Artec gets about 10 stations while the Zenith gets about twice that number. At this point, I am not sure if the Artec is defective or if the Zenith from 2002 has a hotter front end.

Its good that you tested them quite thoroughly side-by-side so that we have a proper A-B test, so I would say that your Artec is a lemon. Maybe try a replacement Artec from that seller or else try a different brand/seller and let us know what happens.

I have a theory about what is going on if it turns out the new box was working properly after all, but I'd be getting ahead of myself with that until we see what you want to do.

[jbracing24]

The Artec does not appear to be damaged but why does it get so few stations or get some of the same stations with an obviously weaker picture?

My experience with the T3AP is quite the opposite. I am also running the older Samsung T451 off the same antenna array. While the Artec is simply a converter box while the Samsung is an HDTV tuner, I get far more channels on the Artec. For example, WUTV Channel 29 (14) always comes in on the Artec. In order to get 29 on the Samsung I have to move the rotor on one of my antennas.

[bentoronto]

Aha. Many thanks, as always, to stampeder and jpracing24. Yes, a defective unit seems a plausible hypothesis. I hope the retailer will agree. And I hope he will still be sympathetic if I have to return a second freshly-opened box to him too if it, alas, proves no better too.

Ummm, maybe my motorcycle saddlebags are not a good travel environment for tuned circuits, even digital ones?

Here's another observation: I think I have a quite directional yagi at 30 feet, but one station from 60 degrees off from the antenna direction and 30 miles seems to come in strong. I mention this because some distinguished posters (and moderators) thrive on intellectual puzzles.

At the risk of being laughed at, I'm surprised at how very similar the picture is for S, video, or even RF. Must be my aged eyeballs. What ever happened to those late night broadcast test signals?

[bentoronto]

My confusion (or surprise) is getting worse.

I tried my putatively-defective Artec T3AP-LL at a neighbour's house (LG HDTV, CM 4221 4-bay antenna). It again brought in many fewer stations. (It is possible that the Artec also has a higher threshold for quality and just doesn't attempt to play some weak channels that other units will try to play. That could confuse the "data" somewhat.)

Soooo, the store kindly replaced it with another. The remote didn't work. Sooo, after another trip, got another which seems to be OK.

But the Zenith is still better. My conclusion is that the 2002 Zenith Generation Two chipset tuner has a better/hotter/quieter front end and works better than the Generation Five/Six Artec and clones. That is kind of in line with the way antenna pre-amp mavens think too: you need a subtle balance of amplification and noise floor and there's no substitute for low noise floor.

I further conclude that the Zenith, being so good, deluded me into thinking my 20 year old fringe Yagi installation was satisfactory; now i think it is the weak link and with upgrading, I should get consistent summer Buffalo PBS reception with both tuners.

For moment, debating if i should bother with an antenna pre-amp (such as the 12dB Winegard that is resistant to overload) to feed 75 feet of cable and one splitter? I hate components that I can't fool with myself when they are up on my roof. Maybe I should install the pre-amp a bit closer to ground level?

Real PIA for me is that the alpine ladder climbing aspect is too challenging.

[stampeder]

This does not speak well for the Antec boxes. I wish we could test another ATSC tuner or converter box brand like a CM7000 at your site. Until then I'm still not ready to share my theory from Post #876 but if I'm correct I'll call it the bentoronto effect.

[bentoronto]

I'm glad to do more testing although I feel more comfortable reading data off a meter than counting up weather-variable channels. Anybody who has a splitter and a TV with multiple inputs can do the comparison as well as I can.

Aside from safety benefits, does reception improve when you use a ground spike or water-pipe antenna ground? Not even my TV house outlet is grounded at present. Are lightning arrestors justified and are they unharmful to the signal?

[EdT]

Lightning arrestors is a minimum, but a 8AWG ground wire is still best since you can ground it to a water main or ground wire as your coax enters the house. I have done several installs where I have the coax follow the electrical fittings into the house and just use a grounding block to ground it to the electrical box main.

[bentoronto]

Thanks for reply.

But does it help reception? Why?

Are ground loops an issue (as in hi-fi installations) since the equipment must be grounded through the house wiring?

Today's idea: I'll use my old yagi and a direct lead-in for FM reception since a new CM4221 can't be any too hot for FM. Anybody know? But I'll cut off the UHF director bars on the yagi to reduce the height on the pole and reduce interference with the CM4221. I'm still not sure if I should include a Winegard HDP269 overload resistant pre-amp.