1080i, 720p on DTV Tivo HD

[cnweber]

I just got the DirecTV Tivo HD box and I can't get 1080i or 720p on any of the HD channels. I am able to get 480p. My Mitsubishi TV does support 1080i and 720p and is connected to the DirecTV box by component video. I am able to switch between 480i, 480p, 720p, 1080i but don't get a picture for 720p or 1080i. Any theories on what could cause this problem?

[jazzsax]

Older Mitsubishi HD TVs did not support component HD. They used an RGBHV signal. How old is the TV and what model?

[DubC]

Do you have any other cables (i.e. composite or RCA) running from the Tivo to the Mits?

[cnweber]

The TV is a Mitsubishi WS-55711 and the component video is the only connection from the HD Tivo to the TV.

[JohnTivo]

Since this model only has one set of component inputs that allows 1080i, but your seeing a picture when in 480i & 480p, then my theory is that you've connected the HR10 to the wrong set of component inputs.

Change to a different set of component inputs and see if it works then.

[cnweber]

Thanks, I did not realize that the multiple sets of component inputs were not identical. I will try switching when I get home.

[mkbruce]

Thanks, I did not realize that the multiple sets of component inputs were not identical. I will try switching when I get home.

There are three component video inputs. Two of them are 480i/480p only, while the third is 480i/480p/720p/1080i.

Magnus

[BillyT2002]

I think you have plugged in the RCA (composite) video cables into the back of the television and not true component video cables. Either that or you have your television set to the wrong input while viewing.

[cnweber]

Problem fixed! JohnTivo was correct. The component video cables were connected to the wrong set of inputs. Thanks everybody for the quick and helpful responses.

[Guindalf]

I think you have plugged in the RCA (composite) video cables into the back of the television and not true component video cables. Either that or you have your television set to the wrong input while viewing.

Just for information, the only difference between "RCA (composite)" and "true component" video cables is the color! The standard RCA cables are Red, white and yellow whereas the component are red, green and blue. However, provided you keep the sequence the same, you can use either for either purpose.

Purists may say there's a difference in quality and the signal strength may fall 0.00001% or something, but for the average mortal with only two eyes and one set of ears, this will suffice.

[AbMagFab]

Further, the coax-digital audio cable is the same. As is the sub woofer cable.

It amazes me how you can go into a store and pay:
$9.99 for R/W/Y RCA cables
$39.99 for R/B/G Component cables
$49.99 for Orange digital coax cable
$59.99 for Sub woofer cable

And then double that if you decide to get ripped off by buying Monster cables.

They're all the same thing. If you are really worried about interference or quality, make your own RCA cables out of quad-shielded coax for about 5 cents a foot. Not too flexible, but better quality then anything you can buy pre-made.

[willardcpa]

.....If you are really worried about interference or quality, make your own RCA cables out of quad-shielded coax for about 5 cents a foot. Not too flexible, but better quality then anything you can buy pre-made.Apparently you have not seen my attempts at such handywork. :cool: ;)

[Guindalf]

Further, the coax-digital audio cable is the same. As is the sub woofer cable.

It amazes me how you can go into a store and pay:
$9.99 for R/W/Y RCA cables
$39.99 for R/B/G Component cables
$49.99 for Orange digital coax cable
$59.99 for Sub woofer cable

And then double that if you decide to get ripped off by buying Monster cables.

They're all the same thing. If you are really worried about interference or quality, make your own RCA cables out of quad-shielded coax for about 5 cents a foot. Not too flexible, but better quality then anything you can buy pre-made.

Don't even get me started on the price of cables! See the other threads on them for my view.

I bought a new receiver last week so I ordered a 3' Toslink and a 3' HDMI cable just in case I needed them (I used the Toslink, but the HDMI is spare). Prices?

BB prices - Toslink $21.99, HDMI $74.99 = $96.98 (+tax $103.77)
Monoprice prices - Toslink $2.67, HDMI $5.80 (shipping $4.05) = $12.52

[rminsk]

They're all the same thing. If you are really worried about interference or quality, make your own RCA cables out of quad-shielded coax for about 5 cents a foot. Not too flexible, but better quality then anything you can buy pre-made.Quad shielded are not good for video or audio cables. They are made for different frequencies and attenuate the signals you are interested in.

Quad-shield has two layers of braid, but these are ordinarily only 40% and 60% coverage braids (Belden 7916A, for example), yielding a net coverage of 76%. To make matters worse, these thin shields are usually made up of aluminum--cheaper by the foot than copper, which is important if you're wiring a whole city with cable TV service, but significantly less conductive; compare DC resistance of 2.8 ohms/thousand feet (Belden 1694A) versus 4.8 ohms/thousand for quad-shield, versus 9.0 ohms for the single aluminum braid/foil combination of 9116. To make matters still a bit worse...the center conductors of most (though not all) quad-shield cables are copper-coated steel rather than solid copper, and consequently are not well-suited for any application other than the CATV distribution for which they were designed.
...
As can be seen, at baseband video frequencies (applicable to component video, composite video, s-video, and rgb, and represented here by the range of 5, 10 and 50 MHz), the precision video cable with 95% copper braid outperforms quad shielded cable by about 2 to 1.Quad shielded cable does have it's place, just not in the home theater setup. If you want a quality video interconnect then make your own cables out of something like Belden 1505F, 1694A, 7710A, or 7787A and use a 75-ohm connector like a Canare (not really 75-ohm but as close as you can get). Sub woofer cables are more susceptible to low frequency hum and need better shielding. Something like Canare LAV-77SA (double braid) cable would work. For regular audio interconnects use 1505f because of the lower capacitance. The subwoofer can handle the higher capacitance of the LAV-77SA because of the lower frequencies.

Cables are not "all the same thing". They have difference resistances, capacitances, shielding, ... You have to look at the characteristics of the cable and what the cable is going to be used for

[Guindalf]

^

See? Told you! :rolleyes:

[tucsonbill]

Quad shielded are not good for video or audio cables. They are made for different frequencies and attenuate the signals you are interested in. Nonesense. All coaxial cable is by definition lossy cable, but attenuation is a direct function of frequency and is less for these frequencies, not more.

WRT DC resistance , who cares. If I ever contemplate any 1000 ft long cables I guess I'll start worrying.

Quad shielded cable does have it's place, just not in the home theater setup. It might have a place, but I agree, not for baseband video. Why tolerate the stiff, nasty stuff when it doesn't do anything for you? The point of the quad shield is the extra shielding. Not usually an issue in this environment. Or, if it is maybe you ought to investigate the source of the offending emissions. Sub woofer cables are more susceptible to low frequency hum and need better shielding. Something like Canare LAV-77SA (double braid) cable would work. For regular audio interconnects use 1505f because of the lower capacitance. The subwoofer can handle the higher capacitance of the LAV-77SA because of the lower frequencies.WOW! If you're worried about radiated interence in the subwoofer range you've got some serious currents in nearby condutors. (Okay I know everyone's system isn't as modest as mine powerwise.)
Cables are not "all the same thing". I agree, but most work pretty well, and some are sold for far more than they're reasonabll worth. They have difference resistances, capacitances, shielding, ... You have to look at the characteristics of the cable and what the cable is going to be used for. And if you know enough about the effects of those various parameters then you probably know enough to understand the fallacy of applying transmission line theory to very short audio frequency cables. It's not that the formulas don't hold, it's just that the answers at these frequencies are trivially negligible.

My apologies, Guindalf. I'm well old enough to know better, but I just couldn't stop myself. I guess I'm 'alf off today.

[TyroneShoes]

...attenuation is a direct function of frequency and is less for these frequencies, not more...The point of the quad shield is the extra shielding. Not usually an issue in this environment... I think maybe some of us could get a little confused by all of this. We are comparing cable with a characteristic impedance designed for broadband RF transmission (such as RG-6 or RG-59) to garden-variety multi-conductor or single conductor shielded cable typically used for baseband signals, and those are really two different animals. Coax and shielded cable are similar in that they use one conductor as a shield, but for coax the relationship of the dielectric in terms of how far it separates the conductors as well as the physical size of the conductors plays into its attenuation at frequency over distance. For shielded cable, while this inevitably also comes into play, it is negligible in these sorts of applications. IOW, coax is designed for one job while shielded cable is designed for another, even though occasionally one can sub for the other in a particular instance.

But, quad-shield cable is typically for RF signal transmission, and using it in a home theatre for baseband signals could be of questionable value, which is I guess another way of stating the same point Bill is making. Also, it is unimportant for the connections from your dish or switch to your STBs, as there is little interference in that band. Quad shield is much more important in a cable headend, and is typically used there exclusively, but it is rarely used for drop cable by most cable MSOs.

...If you're worried about radiated interence in the subwoofer range you've got some serious currents in nearby condutors... Actually, there is a valid reason to have good shielding in a pre-out sub cable. Since it carries signals in the same frequency range as AC, and sometimes for longer distances than most short jumper cables, it is susceptible to induced hum, especially if it runs in the same path as AC (which should be avoided for that reason). But any good cable will do, so paying a premium for a "sub" cable might not be a good bargain.

Usually unwanted hum in the sub channel is due to a ground loop, and not from induced currents, meaning in that case better shielding will be of no help. You need to lift the ground (shield) at the sub end to fix that.

For any baseband cable carrying analog signals, good shielding is a good idea. But the cheapest cable you can buy is usually good enough for digital signals, because shielding is not that important when the signal being carried is essentially immune to induced currents. Just like DT, you either have the signal unaffected at the other end, or you have no signal at all, but you will not experience degradation of a digital signal from a cheap cable. Only if the cable cuts out occasionally do you really need a better one. So, ironically enough, save your better cables for analog connections and use your cheapest for digital.

Bottom line, use the best you can get at a reasonable price, but don't pay extra for quality you don't need or won't see or hear a difference in, and certainly don't pay extra for name-brand cables. These folks prey on your superstitions, just like door-to-door weasels prey on old people with "furnace cleanings" and aluminum siding.

If you price out HDMI, DVI, and component cables, it looks like you could pay more for a set of those than many of us paid for the HR10 in the first place, and it came bundled with all 3 of them.

[tucsonbill]

Actually, there is a valid reason to have good shielding in a pre-out sub cable. Since it carries signals in the same frequency range as AC, and sometimes for longer distances than most short jumper cables, it is susceptible to induced hum, especially if it runs in the same path as AC (which should be avoided for that reason). But any good cable will do, so paying a premium for a "sub" cable might not be a good bargain. Point taken. Since I don't own a powered subwoofer, I was thinking speaker level. Line level signals should always (there's that word I promised not to use) be shielded. The only cables that I build are RF interconnects, for which I use stanadard RG6 (infrastructure wiring) or (GASP!) RG59 (patch cables). In all cases my philosophy is always try the free thing first (i.e. came with the equipment, found in your junk box, etc.), cheap next, and escalate cost only when there's an obvious need.

[TyroneShoes]

I like the way you think.

And a speaker-level sub is one of the trickiest installs, requiring the heaviest gauge cable you can get and the shortest run practical. I had to chuckle at the "(GASP)", as there is a lot of prejudice against RG-59, while in reality it is electrically identical (other than attenuation) to RG-6 and typically a better choice in short runs or for jumpers.

[mcdougll]

I like the way you think.

And a speaker-level sub is one of the trickiest installs, requiring the heaviest gauge cable you can get and the shortest run practical. I had to chuckle at the "(GASP)", as there is a lot of prejudice against RG-59, while in reality it is electrically identical (other than attenuation) to RG-6 and typically a better choice in short runs or for jumpers.

Ok, I was following this thread with some interest, having no intention of getting involved, but I just have to ask about this.

If RG-59 is electrically identical to RG-6, then why does RG-6 work and RG-59 not work when connecting a DTV reciever to the sat dish? In other words, how can you say they are electrically identical?

[TyroneShoes]

Well, the quote "electrically identical (other than attenuation)" qualifies the answer I gave earlier. IOW, if attenuation is not a factor, then they are pretty much the same, and either will do the job.

And they truly are "electrically identical" in these ways: they both have a 75-ohm characteristic impedance, and they both have the exact same frequency response curve. In transmission-line technology terms, they both appear to the source as a 75 ohm resistive load, or as an infinite waveguide. Your dish, multiswitch, and STB have no idea whether you are using RG-6 or RG-59, just whether there is enough signal at the desired frequencies or not, and in many cases, either will work just fine.

The difference is in the attenuation per length at any given frequency. RG-6 attenuates signals at any frequency about 3/4ths of what RG-59 does over identical lengths of cable, which means for short runs, the difference between one and the other is negligible. But, since dish installs sometimes reside 125 ft or even more from the STB, most DBS installations are recommended to be done with RG-6. But RG-59 will work just fine under 90 ft. or so.

The DC loop resistance (which can be thought of as how much the signal is attenuated at 0 Hz going both directions in series) is also important because the STB talks to the switch using DC. If the distance is too far (which limits the use of RG-59 to even-shorter distances) the voltage drop can be excessive, and then there can be problems.

Short answer: RG-59 can often do the same job for a DBS TVRO install with an end result of equal performance, but RG-6 is usually recommended because sometimes the distances are too long for RG-59. RG-59 is not prohibited for DBS installs, but RG-6 is typically recommended.

[Budget_HT]

My original 18" x 24" DirecTV oval dish came with a 4x4 multiswitch to mount on the back of the dish. The jumpers provided for connecting LNB outputs to the multiswitch inputs were all RG-59.

Having several years of AF and RF transmission line design/installation/testing behind me, I agree with TyroneShoes wrt short distances for satellite cables. Without a full understanding of the electrical characterics of RG-59 and RG-6, most folks simplify the problem and solution by using RG-6 for everything satellite. This includes DirecTV and Dish Network installers, most of whom are not electronic technicians by training. I assume that is intentional on the part of D* and E*. It also means they only have to carry one type of cable.

[TyroneShoes]

Well, two, actually, those being "house" or un-messengered cable, and siamese-messengered cable for aerial drops. But both are typically RG-6 for that reason.

There is one advantage of RG-6 over RG-59 not yet discussed, which is that the physical size of RG-6 lends itself better to cable TV installations in that it holds up in weather for a longer period of time. When I worked for CATV back in the day we cut our truck rolls in half simply by going from '59 to '6.