Cable TV - Some Channels hum and are fuzzy

I have cable tv hooked up in several places in the house. For some reason some channels on 1 of the TVs are fuzzy and make humming noises. For the fun of it I hooked up another TV to the line the problem TV is hooked up to. The other TV doesn't have this problem.
Does this suggest a problem with the tuner in the one TV? Something else? The problem TV is about 7 years old.
Regards
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Check the settings on the problem TV. On some TV's you have to tell it what kind of input you are using, make sure its set on Cable. Other than that, try the problem TV at another spot in the house to determine if it is the TV or perhaps something in the cable line.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Could be a *cheap* cable. Try switching the cable (from TV to wall) from good TV to bad TV and see if that fixes problem.
The best cable is called RG-6.
The difference is the "shielding" inside the cable. This keeps outside electrical "noise" out of the cable.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

RG-11 is a hell of a lot better than RG-6.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

But not worth the trouble inside a home in most cases.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Different TVs have different sensitivity. That TV might want an amplifier on the cable to work right. How you wire splitters can affect signal strength. If you go through multiple splitters, the signal strength may be weakened more on some links than others. If, for instince, you have on TV hooked up to a two way splitter, and the second output from that splitter going to another 2 way splitter, going to 2 more TVs, the second two TVs each get 1/4 the signal of the first TV. Using a single multiple splitter sized appropriately for your needs will even up the signal strength. Or, tou could rewire your multiple splitters to give the problem TV the stronger signal. Cheap splitters can also be a problem. My cable company told me to never use radio shack splitters, and they were happy to give me good ones, as bad splitters can affect your neighbors signal also.
Bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks for the replies so far. I tried some RG-6 but it make no difference. The problem TV is to large to move to try at another outlet.
I did find something very interesting though:
If I tune the TV to one of the fuzzy channels, then turn the TV off/ back on the channel comes in perfectly clear. If I change the channel and then change back the channel is fuzzy again. Turning the TV off and then back on (when on the fuzzy channel) always fixes the problem (until I change channels again).
Also - I had an old calble box lying around. I tuned the TV to channel 3 and then used the cable box as the tuner. The fuzzy channel are perfectly clear using the cable box.
I'm thinking the tuner in the TV may be flakey. Thoughts?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

My tuner is shot. I can use the alternate Input though. (Try hooking your cable up to a VCR and connecting the VCR into the TV set using either the channel 3/4 settings (predictable problem because of a bad tuner on the TV) or use the alternate input on the TV (channels come in clear because the tuner is OK on the VCR.) If the signal is bad from the VCR to the alternate input on the TV set, you probably should get a signal check from the cable company. If the signal is good from the VCR to the alternate input yet bad straight to the coax input, you should consult with a TV repair shop.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
says...

The tuner isn't locking onto the stations properly. If the tuner has no user modifible settings, like an AFC on/off switch or fine tuning dial (a set your age likely doesn't) then there isn't anything you can do short of having a shop try to fix it.
It's possible the set will do better with a better signal and you should follow the steps for minimizing the number of splitters and look at their quaility.
whosbest54
--
The flamewars are over...if you want it.

Unofficial rec.audio.opinion Usenet Group Brief User Guide:
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 13 Dec 2005 13:22:02 -0500, "homerlex"

That's a nuisance, but I have a smiliar if smaller problem. When I turn the tv to channel 3 and go to the other room to turn on the VCR, I don't get the vcr signal at all. When I then change stations and then go back to channel 3, the vcr signal is perfect.

Yes it is. Is it still under warranty. If not, I'd want to know that other copies of this same brand and model worked better before I even considered trying to have this repaired.
Still, an external RF amplifer might be the first thing to try.
I have 8 tv's in my house, including in the unfinished attic, one bathroom, and the laundry room. All connected to the vcr, and when I had cable, to the cable. But I also have 2 RF amplifiers, one with 4 outputs and one with 2. No tv is on a branch with more than one other tv. That is, there are no more than 2 tv's on the same output of an amplifier.
I didn't do this on principle. I would hook them up and when quality through the coax went down, I bought another amp. At radio shack. It always fixed the problem. They've been working steadily for as much as 20 years. One is probably covered by old clothing. I don't recommend that, but it doesn't overheat. These are tiny signals so after amplifying them they are still very small.
I also have an amplified antenna, for off the air reception. (since DC stations aren't carried on Baltimore cable.**) For some tv's, it's signal is too strong, and for some stations on those tv's I have a A-B switch and I disconnect the antenna and use only the coaxial cable that goes to that switch. It may be coaxial (shielded) but it still picks up enough signal on strong stations. (Or like I said, maybe it is picking up the signal via the unshielded wires inside the tv, between the connector and the tuner.)
**Useful tongiht when there is some stupid movie on ABC Baltimore, but a series of good sitcoms on ABC DC. I wonder why they do that.

Remove NOPSAM to email me. Please let me know if you have posted also.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I suspect that you're right about the tuner being flaky, especially after you cleared it up with an old cable box. The cable box is working as a substitute tuner and as long as your tv gets ch 3 (or 4 whichever it operates on) clear, use the box instead and it's a cheap way to sidestep the problem. Another way to do it if you don't have an old cable box lying around is to buy a cheap vcr and use it in the same way. After hooking up the vcr, select vcr on the tv / vcr option ...... you should be able to change the channels that you're viewing with the vcr.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

This is a very common problem and very easy to fix. All you need to do is add a "cable amplifier" (froogle on that) to your setup. The problem is that every time you split the signal the signal strength is divided equally (regardless of the quality or brand of the splitter). At some point you add too many TVs and Cable boxes and VCRs the signal strength is degraded too much and it usually shows up on certain channels as snow with little pattern as to which number is effected and each TV will react differently.
A single (one in and one out) 20db amplifier at each TV will work but a better solution is to get a multiple port amplifier (like 1 input and 8 outputs) and send each TV its own amplified output. In this configuration, I guarantee you will not have noise on any channel unless a cable is damaged or a F fitting is very loose. The amplifier is powered by a wall wart power supply
more db means more amplification. you only really need high gain (like 40db) if you plan to split after the amplifier. If you go directly to each TVfrom the amp, a lower gain like 4db per output will be enough.
If you have Cable internet, you need a bi-directional amplifier or split the signal before the amplifier and send an unamplified cable to the modem.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

And consider that a too-strong signal (such as with unnecessary amplifiers) won't work any better than a too-weak one.
--
12 days until the winter solstice celebration

Mark Lloyd
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Where did you get that from?
A single amplifier will not clip the signal. As long as you don't put two or more in series, the signal will not be clipped (sometimes you can but lets not cover all the permutations). High amplitude at the tuner input is almost never a problem, the amplifiers have a maximum amplitude anyway which cannot be exceeded. Clipping of the signal due to amplifying an already amplified signal could occur, that is why the single distribution amp is the standard solution.
All this other stuff about tuner sensitivity and miaalignment might have made sense 20 years ago with mechanical tuners but with a varactor (electronic) tuner, fine tuning is automatic. If it were to fail, you would get a scanning effect on all channels where it looks like someone is fiddling with a fine tuning knob inside the set. I just fixed this on my old Sony by fixing a cold solder joint on a coil.
All that other crap about marginal cables, splitters and fittings is only a problem with low signal strength. Once boosted, even the crappiest cables and connectors work pretty good. (ok a bad connection can show on a channel but it is less common and can usually be fixed by tightning) If you have more than 4 tuners attached to a cable, you need an amplifier.
Upgrading cables and splitters is like replacing the alternator and regulatoer in your car only to find out the battery was just dead the whole time. Take my advice and buy an amplifier before you tear everything apart. It really does work. I have done this myself and for two friends with identical problems.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

True. That's what causes clipping.

Such as a cable TV or modulator output that's not as weak as expected, or a too-sensitive TV tuner.

It was a new Sanyo, where I last noticed a problem with excessive signal strength.

IF the signal is too weak. Otherwise, the amplifier is likely to make it worse.

It (the amplifier) is something to try. Be sure to notice if it makes the signal worse.
--
9 days until the winter solstice celebration

Mark Lloyd
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 13 Dec 2005 08:24:07 -0800, snipped-for-privacy@homerlex.mailshell.com wrote:

Hook up that tv somewhere else and you';ll have an answer. Why stop with only half of the testing?
Also, try using it with an antenna. If it only has a coaxial connector, stick a piece of uninsulated wire an inch or so into the hole in the middle of the coax connector.
For channels 13 and below, there is no need to change the internal setting from Cable to Antenna. The frequencies are the same.
(Close to a transmitter, there is usually no need to use any antenna at all except for channel 2, and maybe up to channel 7. The wire inside the tv, from the antenna or cable connector to the tuner acts as the antenna.)

Remove NOPSAM to email me. Please let me know if you have posted also.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Some cable systems put the channels on frequencies that are slightly shifted, to reduce some types of interference. Some TV's have settings to switch to the different frequency schemes. Look options on your TV's menu system, or a physical switch on the TV, that say "HRC", "IRC", "Special", "Normal", etc. If you find these try changing the settings to see if one clears up your problem.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sounds like the signal at that particular drop of the cable is too hot for that TV's tuner. In other words the TV's tuner is too sensitive. This can be cause by the tuner being mistuned somewhat. It doesn't say below, but did you hook up this problem TV to one of the other drops to see if the problem moves with the TV? Brian

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.