Axiom Home Page Forums General Discussion Advice from Axiom Owners OT:New TV purchase?

I was over at BB on Sunday and pulled the trigger on a RCA rp hdtv monitor and a hd dtv receiver. I think I may have boo-booed with the RCA. While the slim pickens of hd channels look very good, the conventional channels look very blurry and are hard to watch for extended periods. I went back and asked one of the sales reps if all the hd tvs looked this way. He said unfortunately they do. I find that hard to believe. My conventional tube tv looked much clearer and crisper with conventional channels. Is it the cheapo RCA that is the culprit or is the sales rep right?

We have a Mitsubishi RP CRT with hdtv tuner, but were runnin' with cable-in on 1080i and yes, the HDTV channels are fabulous. Everything else.....

.....Well....now that's another story. And the story has many chapters

Some are very very good

Some are downright yuckyand difficult to watch.

And some are right in between. There dosen't seem to be any obvious rhyme of reason for it other than some channels are delivering to us a better PQ, perhaps right from the source!

My Daughter is having the same situation as we are(no surprize cause we subscribe to the same cable company)but her picture sometimes looks just a little bit better on her Toshiba(one of the later, much improved models)simply cause she has a smaller RP CRT than we haveSlide up where you're looking at the same angle of view and they are the same.

So..in our limited population of veiwing data, we have a "could be the input at that" responce



(however......RCA is not the most respected brand of sets at the moment either, or at least wasen't at the first of this year)

Do you guys have cable or satellite? From my experience, satellite is much better than cable for non-hd channels.

On my Sony 32 crt all channels are perfect above 13 on cable. 2-13 (all the networks) are very bad. More snow and slihouttes than you would think. My satellite quality was a little better on SD, but not a lot
On Sony plasma, the HD on satellite had no comparison until I went OTA with an antenna on the chimney. NBC and ABC HD are quite stunning. Other channels look like analog converted to digital.

Welcome to the confusing HD club. Yes, D* HD can look good to great. IMHO, OTA looks better.

Unfortunately, SD channels can vary from good to horrid. I've found that on my EDTV plasma, SD can look quite good, it really depends on the compression that D* has on the particular channel. HD displays can also make mediocre SD looks worse, since you have more pixels. That's probably what's bother you. I agree, CRT can look cleaner, sometimes a LOT cleaner w/ SD.

You might check the AVS forums for suggestions on how to possibly calibrate your RCA for better viewing. As your gut tells you, don't believe the rep. SD can look pretty good, just depends on your source, monitor and settings.

BTW, which receiver did you get? Did you get the HD Tivo? Those have gone down to $299 w/ rebates.

I think the TV is fine - it is your source that is the issue. I have used both DirecTV and Comcast Cable and the regular stations on D* looked a whole lot better than the ones on Comcast. The standard channels were so bad on Comcast, that I only use my 47" HDTV for Hi-def or widescreen programming only.

I have DTV. I got the H10 model hd receiver for $100 less because I bought a TV. I'm thinking I might return the RCA and upgrade a bit, thinking maybe a Toshiba would be a better set.

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On my Sony 32 crt all channels are perfect above 13 on cable. 2-13 (all the networks) are very bad. More snow and slihouttes than you would think.

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Alrighty, finally back to a topic I can chime in about. What you're experiencing, Bug, is overmodulation of your cable signal. Chances are you have some lower bandwidth capable cable in your place, and as higher and higher channels came out, someone (perhaps a previous owner) complained that the higher channels were snowy. The cable company's knee-jerk reaction is to "cook up" the signal strength to make up for the falloff in the higher frequency ranges, but that overmodulates the lower frequency ranges (channels 2-13 VHF) that don't get attenuated by the cable in your house.

Same thing happened when I moved in here, all the cable was original (back in the 2-13 channel TV dial days) badly shielded RG59, which carries 2-13 very well, but rolls off in the higher channels. When I replaced it all with quad-shield RG6, which doesn't exhibit the same rolloff characteristics, ALL the channels were overmodulated and showed "ghosting" (which is actually bleed through from adjacent channels)... I called the cable company and let them know that I wanted them to lower the signal strength on their side, by using a variable RF "pad", I determined the best signal was at 6dB lower than what they were currently driving.

The cable company is very resistant to come out and tweak the signal strength that they're sending, it's kind of a "you gets what you gets" situation for them. It took two or three calls and finally me throwing up my hands and telling them if they wouldn't adjust their signal for the best looking off-air quality for me, that I'd switch to the digital cable through the phone company where it wouldn't be an issue. They came out, padded my cable at the pole, I took my pad off and all has been right since.

Not much you can do if all your in-wall is rated for less than 900MHz, but if it is, a little testing with either variable or static pads may give you a bit more insight.

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My satellite quality was a little better on SD, but not a lot

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Chances are that you have one "satellite capable" (usually into the gigahertz range) run of coax from the satellite to your set top, which would further reinforce that theory.

This is one of those mid-investment in labour (pulling new cable through walls), small-investment in money (coax is cheap), big-return type things. People tinker with getting that... maybe... just... a little... no, wait, I think I hear it... return on $6000 interconnects and then overlook something as reasonable as this.

Bren R.

Our cable is the worst service company going. They have a whole city contract and pretty much do as they please. My only other options are Sat and OTA. Done Sat (voom) and more channels than I ever watch plus little HD without voom. No local HD. So I watch OTA locals and cable for 14 and up.
Turns out the guy who installed my antenna knew the problem exactly as you described, but cable co is NO help.

I gave the local independent TV technician a call yesterday. He told me the numero ono question he is asked is, "I bought a HDTV, why is my TV picture horrid?" He said this is because modern HD tvs lack the proper "interlacer." He also said interlacers are expensive, so TV manufacturers cut that corner.

That sounds suspicious. I assume he is talking about a de-interlacer since SD signals all come across interlaced but are often de-interlaced so they can be displayed at 480p rather than 480i.

To the best of my knowledge the de-interlacers in modern HD TVs are actually pretty darned good. I was under the impression that was one of the high points of modern TV design. He is right that de-interlacers are expensive but they are the heart of modern consumer electronics (de-interlacer is the same hardware as the upconvertor) and I don't think too many corners are being cut there.

EDIT -- I just re-read your original post where you said that the image was blurry... that *could* be an artifact of de-interlacing... do you know if you can set the TV into a different mode so that it actually displays an interlaced image when looking at standard TV ? That would bypass the de-interlacer and give you a "normal" TV picture if the de-interlacer is the problem.

Also one thing to think about is that you don't want to stretch non-HD programming as that can accent any defects that you are seeing. So make sure SD programming has black bars on the sides of 16:9 display.

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He said this is because modern HD tvs lack the proper "interlacer."

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As Bridgey ( ) pointed out, if I understand what the tech is saying correctly, that would be a deinterlacer.

And if your TV is showing an interlaced signal on a progressive scanned screen, believe me, it wouldn't be a bit fuzzy/blocky/soft, any horizontal motion would show interlacing artifacts.

See these images (rendered 'em out quick for illustration)

In each case, the gear is moving right to left, the stopwatch bottom to top of frame.

Image #1 - this is what a SD NTSC signal would look like on a progressive scan monitor without any sort of deinterlacing before scaling (to 720P give or take).

Image #2 - same image, but deinterlaced (top field bicubic) prior to scaling. Note jaggies on the edges. Top field is the "earlier" field, so the positions have moved.

Image #3 - here's the same image (again, top field shown) rendered out in native 720p, no sclaing, no interlacing.

Hope that help illustrate.

Bren R.

I just did a bit more reading on this... looks like some deinterlacers will blur the image to cover artifacts when running in "bob" mode (essentially de-interlacing a field at a time, displaying each line twice), and will fall back to "bob" mode unless they can recognize patterns in the incoming video. A DVD player can get cues from flags in the MPEG stream but I don't think those flags get passed through into the video.

I'm starting to wonder if it was such a good idea to get the higher end Sony CRT (with progressive scan and deinterlacing) for my parents if they are going to be mostly watching standard NTSC TV programs. I hadn't realized how many artifacts are generated when de-interlacing normal video...

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I'm starting to wonder if it was such a good idea to get the higher end Sony CRT (with progressive scan and deinterlacing) for my parents if they are going to be mostly watching standard NTSC TV programs.

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Well, any time you're mismatching a signal there will be issues... even an interlaced image going to a monitor at non-standard resolution that is interlaced... the interlacing of the source is always every second line to a field (say for ease of math it's 480 lines).. and the interlacing of a CRT will be every second line line to a field (say a 960 line resolution)... so each of the interlace fields of a SD source will cover two lines on an interlaced CRT (upper and lower fields, which are displayed 1/60th of a second apart) unless some further manipulation is done to make up for it.

There is no easy answer. There is no good solution. That's why I still have a SD television.

Bren R.

My fuzzy TV is on both Sony SD crt and Sony HD Plasma on the 2-13 channels with the problem Bren described earlier. Is there a home fix since the cable company won't respond?

Gee, this place is a wealth of technical information I wouldn't even begin to understand. I am glad I picked up the hi-def receiver since it has dolby digital audio. That is way .

Bug - is this your own house?

If so, you can replace any of the old coax (anything not marked, or rated for less than 900MHz) which will get rid of the rolloff on the high frequencies, you should then have too strong a signal uniformly across the board.

RadShack has this, an infinitely variable pad but I'm not a huge fan of having a sweep pot left in a signal path.

A bit of guess and check with these would be more my style... try maybe 10dB, if the ghosting goes away but the channels get snowy, it's too much, try a 6 or 3dB.

(Not pushing any of these site/distributors, just giving you an idea what to look for, both also pass DC in case you have cable internet or for use with satellite systems)

There are also slope compensators that would make up for your cable loss without replacing it, but trying to find one that matches your loss pattern would be mind-boggling.

Bren R.

Oh, a few more pearls of wisdom about cable/CATV while I'm on the subject.

GROUNDING BLOCK = GOOD. Remember to ground your cable as it enters your house. Floating DC current on it makes for all sorts of bad stuff. I'm like a canary for stray voltage - maybe all the Pepsi I drink, I'm the only person I know that can get a yelp-worthy shock off of CATV.

Satellite users should probably invest in some high bandwidth coax - I'm a bit weak on my satellite theory, but I believe, since the major players bundle gigahertz-plus coax with the dish, there's probably a good reason. No need for boutique stuff.

Schwartzen-what? Terminate all unused cable runs with 75ohm terminators, especially if using unpowered splitters, it balances the signal level. Do NOT terminate powered DistAmps (distribution amplifiers)!!!

Bren R.

I can get shocked off of CATV. I always figured it was just my imagination, though.

Somtimes it helps to start small. When I purchased a 50" Sony Grand Wega about a year ago, I got it in part because it was more adept at handling Standard CATV. I got it home and everything looked horrible. the standard channels had strong artifacts, the SD channels looked overly compressed and badly pixelated (blocky). I tried everything on the TV set itself, all my tweaking was not helping. Almost by accident I found that my Scientific Atlanta 8300HD box had a built in upconversion to 1080i feature. Guess what? It worked pretty good. The picture is now equivalent to what you'd get on a CRT. HD is still jaw dropping.