Cable TV problems: degradation in signal

Discussion in 'Archived Threads 2001-2004' started by Andy Kim, May 5, 2002.

  1. Andy Kim

    Andy Kim Second Unit

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    Hello,

    I've got a couple of cable TV problems.

    1) When I have my VCR and TV in the standard hookup(cable into VCR, then VCR to TV), the signal of the cable degrades pretty badly and that's when I'm using the TV's tuner. This is evident with the higher channels. Things past channel 40 get really snowy.

    Now, when I have the cable hooked up directly to the TV however (by passing the VCR), things look great.

    Is this a VCR problem? OR does one expect a cable signal to lose strength with each connection that's added in between (albeit inactive when the VCR is off)? If that's the case then getting a new VCR won't help...

    2) I would like to split my cable so I can send the signal to by bedroom TV but again, the degradation in quality (evident by snow) doesn't even make it worth it. Is there a splitter on the market or a technique out there that will allow me to split the cable so that both TV's show a good picture?

    Thanks for any help

    Andy
     
  2. Mike Matheson

    Mike Matheson Second Unit

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    Andy,

    Regarding your #1, I used to take that situation as normal myself. Someone suggested that in fact it's not normal and that I should replace my VCR--I did. Went with a JVC 9800, which is regarded as having a pretty good tuner (look for past threads). Cable became MUCH improved. The 9X00 series SVHS players by JVC are kind of pricey, but the 7800/7900 models aren't that bad. BTW, rented video tapes have improved dramatically as well.
     
  3. Allan Jayne

    Allan Jayne Cinematographer

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    With a splitter the second TV might work OK but the VCR is already struggling with the signal strength coming its way.
    If you can't get rid of the VCR, you might ttry a booster on the incoming cable feed before the splitter.
    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  4. Wayne A. Pflughaupt

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    Andy,
    I’m willing to bet the cable you had between the VCR and TV is bad.
    The most common problem in RF signal paths is the cables. Check them all. If they are the custom made-type with crimp-on connectors and they look questionable, replace them. I’ve heard that something like 80% of all RF cable with crimped connectors are not terminated properly.
    Also, if you’re using any of those cheap “push-on” antenna cables that come with the equipment, loose them. Use only good-quality screw-on F-connectors, or at least high-quality push-on cables with the round tension rings on the end that maintain proper contact pressure.
    Regards,
    Wayne A. Pflughaupt
     
  5. Tim Robbins

    Tim Robbins Agent

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    I also was getting poor cable reception. I bought a cable splitter that is used for sat system installations ($12 CAD at the local HT shop). I have main feed from wall to splitter, then to TV, VCR, tuner (AM/FM), and TV in another room. Everything looks good.

    BTW, a cable "booster" does just that, but if your signal is poor, boosting it usually makes it worse.

    Tim
     
  6. Andy Kim

    Andy Kim Second Unit

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    Thanks for the responses guys.

    Mike, when I turn the VCR on and use its tuner, the signal is stronger and I get less snow. I would like to keep my VCR off however and not use it and use the TV's tuner when I can. Its when the VCR is off and acts as a bypass that the signal is weak.

    If there's a difference though between VCR's and how they pass the signal when OFF, then I'll definitly consider getting a new VCR.

    Wayne, the cable between the TV and VCR is actually the best cable I have. I did try swapping though and got the same results.

    Tim, the splitter I'm using is pretty old and I'm thinking its of really low quality. Maybe investing in a better splitter will do the trick.

    Thanks for all the help.
     
  7. Mike Matheson

    Mike Matheson Second Unit

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    Andy,

    I think you would find that a better VCR (such as that JVC 7800/7900) wouldn't degrade the signal as much (if any) on bypass.

    I'm no longer running my cable through my JVC SVHS player so I can't do an A/B to confirm--maybe someone else can chime in here.

    Be sure you get a splitter designed for one input and two outputs, not three or four outputs. There's something like a 3dB drop in signal strength when the line is split (or is it 6dB?), and if you jump to a three output splitter--then you've got the signal split TWICE (for a 6db drop [or is that 12dB?]) for two of those three outputs.
     
  8. NickT

    NickT Stunt Coordinator

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    If you picture is a lot worse when going through the vcr, and it's ok when going straight to the TV, then something is not right with the vcr. You shouldn't get that much if any difference by running the cable through a vcr. You've already swapped the cable between the vcr and TV, so that doesn't seem to be it. How does a prerecorded tape look when played? If it looks bad, then try using a composite cable from the vcr to the TV. If the picture is ok with the composite cable, then it may mean the output barrel on the vcr is damaged and is letting in ingress. If a prerecorded tape is ok with the rf output, then the input barrel or the internal splitter or directional coupler in the vcr is degrading the cable signal way to much. It seems to me though that you need a new vcr.

    Also, buy a new 2way splitter rated from 5 to 1000MHz. Using one that looks old might be ok, but splitters aren't very expensive, so get a new one. A two way splitter cuts the signal by roughly 3.5 dB (which is halving the signal) which shouldn't affect your cable signal since you currently have only one tv on cable.
     
  9. LewB

    LewB Screenwriter

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    Andy:
    I was having similar problems when splitting my cable signal for use in other rooms. The higher channels had more and more snow the higher you went. Got the cable co. out to check their end of things before I went nuts tearing up the house. They found the incoming signal was low and fixed that by installing new cable from the pole in the street to the house. The cable guy also told me to get rid of the el cheapo splitters that only go up to 900MHz and use better ones that pass higher bandwidth. He went to the truck and gave me replacements for all the splitters I had in the house for free!! [​IMG] Next thing you know I had MUCH better pictures on all my TV's !!! I was shocked to have such a pleasant experience with the cable company, they even showed up on time [​IMG] [​IMG] [​IMG]
     
  10. Andy Kim

    Andy Kim Second Unit

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    Thanks for all the advice guys. I believe my VCR is to blame.

    What I've done now is instead of running the cable first into the VCR and then out to the TV, I fed the cable into the a 2-way splitter first and from there one goes to the TV and the other to the VCR. And when I need to watch something on my VCR, I just do it through composite video inputs.

    The get way less snow doing it this way.

    The thing is I would like to send a third signal to the TV in the bedroom. Would a 3 way splitter reduce the picture a lot compared to a 2 way?
     
  11. NickT

    NickT Stunt Coordinator

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    A three way splitter does cut the signal more. Two of the three legs lose 7 dB and one loses only 3.5 dB. A two way splitter loses only 3.5 dB on both of it's legs. Put the bedroom line on the 3.5 leg since it has to go a farther distance. You could also use an A/B switch for the TV/VCR since you are only going to watch only cable or the VCR at one time. This way you can still use a 2 way splitter and not cut down the signal.
     

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