Why does the quality of channels from my cable TV provider vary?

June 6, 2010 8:44 PM

Why does the quality of channels from my cable TV provider vary?

Granted, I have an old TV and I'm not using high quality coax cable, but that can't explain why some channels look quite good and others are awful. For instance, Letterman's broadcast from the Buffalo NY CBS affiliate on channel 5 and the picture quality's very bad, while the same program from a Toronto station on channel 4 is much better.

It's like I'm using rabbit ears. Why are only some channels bad? I'd think this couldn't happen with cable.

posted by davebush to media & arts (9 answers total)

Couple of possibilities:

1) The broadcast itself is of that quality. Two channels, even if they're broadcasting from identical sources (the exact same camera at a ball game), can have different equipment in their broadcast process that affects the quality of the image. The way that the signal makes its way from the television station to the cable broadcasting center can also make a big difference--there are a zillion transport mechanisms, from analog cable (like feeds it into your TV) on up to digital subscriber lines sending compressed digital video. (This answer is the most likely)

2) If you have regular, old analog cable (i.e. not digital cable), then the different channels are still different frequencies. Analog cable is exactly like using rabbit ears, only the signal is not propagated through the air, but through copper. In this case, it's possible that your television's tuner or the cable itself is malfunctioning in such a way that some frequencies are tuned better than others. This is not completely unheard of. I've definitely had radio gear (and TV is radio) that liked to tune/modulate some frequencies better than others. But, it is less likely than the first possibility I gave.
posted by Netzapper at 9:19 PM on June 6, 2010

Netzapper - thanks. I do have regular, old analog cable. Would it be worth a shot to upgrade to a better coax? I'm sticking with my dear old TV set till the bitter end.
posted by davebush at 9:33 PM on June 6, 2010

Would it be worth a shot to upgrade to a better coax?

Depends on the length of it. If we're talking about the 3ft length that goes from the wall to the TV, and you can get it for $2.00 at the store. Eh, why not, might fix it. If we're talking about rewiring your whole house, almost certainly not.

Really, like I said above, the probability is much higher that the broadcast itself is merely of the quality that you're seeing. I've observed this effect many times before with both analog and digital cable, and I've never traced it to equipment issues on my end. It's always simply been that the broadcasters have screwed up the picture in some way.

Unless we're talking about static. If there's static, it's either your equipment or the cable company's equipment.
posted by Netzapper at 9:48 PM on June 6, 2010

You say your TV is old. How old? Are we talking rotary channel selector, or something more recent?
posted by Monday, stony Monday at 10:09 PM on June 6, 2010

It could also just be that the cable company's signal distribution amplifiers for ch 3 are older or not configured properly compared to the ones for ch 4. Or it could be that the program signal for channel 3 gets distributed in analog form over more hops (repeaters) than the one on ch 4 which like a photocopy of a photocopy means it slowly degrades. These are all the sorts of headaches that television engineers used to shed tears in their beers over, and the reason why everybody was excited to move to digital. (Of course with digital there is a different problem: the cable company gets to decide how much bandwidth to allocate to each channel, and if they're stingy they can cram more channels into their lineup without upgrading infrastructure by transcoding what might be a 20 Mbit program source down into say 12 Mbit.)
posted by Rhomboid at 10:25 PM on June 6, 2010

There's one more option: incompetence. I worked for a cable station back in the day, and they really didn't give two shits about channel quality unless someone complained. Needless to say, the "premium" channels got a lot of tweaking, and the rest, they just plugged 'em in and walked away. Over-saturated signals weren't unusual, nor were under-fed signals; in the first you'd get washed-out faces and blurriness, and in the second you'd get dark, noisy pictures.
posted by davejay at 10:54 PM on June 6, 2010 [1 favorite]

When I lived near Sutro tower (San Francisco's main TV broadcast site) our cable for some lower channels was really crappy. Once we got a shielded coax, RG5 IIRC, all was well. Are you close to any broadcast locations?
posted by cftarnas at 11:43 PM on June 6, 2010

I get the same picture quality variability on my Comcast analog cable service. Generally speaking, the channels lower-down on the dial, 2 through about 24, tend to be very clear and sharp all the time. Anything above 24, though, can vary wildly from day to day, and from channel to channel. Some will be clear while others will be grainy as hell. One channel (I think it's Disney Channel) will sometimes actually roll, like an old-school TV would. That one is crazy and is a recent development.

Comcast doesn't give two whoops about its analog service, though, so I don't expect this to change.
posted by Thorzdad at 4:33 AM on June 7, 2010

It's worth it to call your cable company and complain. I once had a problem where the higher you went, the worse the quality. The customer service rep said "Oh, we can fix that," and logged a service call.

The next day some cable fix-it person came out, fiddled with things, and magically made it better.
posted by ErikaB at 9:43 AM on June 7, 2010 [1 favorite]