Sorry for posting this, but I know that there are some smart TV guys here.
I've got a cheap TV card that works OK with Linux, except that it has "noise" bars on channels 2-5. It looks OK on channels > 5.
Would it help if it enclosed the card in a (properly insulated) metal box? Should I ground the box?
Thanks,
John
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John Wendel wrote: | | Sorry for posting this, but I know that there are some smart TV guys here. | | I've got a cheap TV card that works OK with Linux, except that it has "noise" bars on channels 2-5. It looks OK on channels > 5. | | Would it help if it enclosed the card in a (properly insulated) metal box? Should I ground the box? | | Thanks, | | John | John,
First, some simple questions: ~ (a) Is the computer grounded 3-wire plug and all? ~ (b) Cable, Antenna, Satellite dish? ~ (c) Using a splitter? ~ (d) Properly crimped cables being used? ~ (e) Type of TV card? ISA, PCI, etc.
James
James Kosin wrote:
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John Wendel wrote: | | Sorry for posting this, but I know that there are some smart TV guys here. | | I've got a cheap TV card that works OK with Linux, except that it has "noise" bars on channels 2-5. It looks OK on channels > 5. | | Would it help if it enclosed the card in a (properly insulated) metal box? Should I ground the box? | | Thanks, | | John | John,
First, some simple questions: ~ (a) Is the computer grounded 3-wire plug and all? ~ (b) Cable, Antenna, Satellite dish? ~ (c) Using a splitter? ~ (d) Properly crimped cables being used? ~ (e) Type of TV card? ISA, PCI, etc.
James -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
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Thanks for the help!
(a) Yes (b) Cable (c) Yes, 2 (d) commercially made cables, I hope they're properly crimped (e) PCI, no brand chinese junk, Philips chip
I plugged the cable into a TV, and the picture looks fine on all channels. So I think the noise is being added by the computer.
Regards,
John
John Wendel wrote:
~ (c) Using a splitter? (c) Yes, 2
Two splitters on the same connection??
-James
James Kosin wrote:
John Wendel wrote:
~ (c) Using a splitter? (c) Yes, 2
Two splitters on the same connection??
-James
Yes, I split the main cable connection into 2 cables (6-foot to TV, 20-foot to computer) and then split the computer cable into 2 6-foot cables for 2 computers. Have I violated some limit?
Thanks for your help.
John
John Wendel wrote:
James Kosin wrote:
John Wendel wrote:
~ (c) Using a splitter? (c) Yes, 2
Two splitters on the same connection??
-James
Yes, I split the main cable connection into 2 cables (6-foot to TV, 20-foot to computer) and then split the computer cable into 2 6-foot cables for 2 computers. Have I violated some limit?
Thanks for your help.
John
No, not exactly.
Every splitter in the chain will cause a signal loss of about 3dB on average. 3dB compares to about 1/2 the signal is lost. Cable companies can make up for this loss by providing an amplifier to the signal coming into the house; but, they really don't like doing that.
You may want to contact your cable company and request a service visit to check the signal quality. They have equipment to measure quality and may even have a solution for your problem.
Good Luck,
-James
James Kosin wrote:
John Wendel wrote:
James Kosin wrote:
John Wendel wrote:
~ (c) Using a splitter? (c) Yes, 2
Two splitters on the same connection??
-James
Yes, I split the main cable connection into 2 cables (6-foot to TV, 20-foot to computer) and then split the computer cable into 2 6-foot cables for 2 computers. Have I violated some limit?
Thanks for your help.
John
No, not exactly.
Every splitter in the chain will cause a signal loss of about 3dB on average. 3dB compares to about 1/2 the signal is lost. Cable companies can make up for this loss by providing an amplifier to the signal coming into the house; but, they really don't like doing that.
You may want to contact your cable company and request a service visit to check the signal quality. They have equipment to measure quality and may even have a solution for your problem.
Good Luck,
-James
Thanks for all the help. I'll try things without the splitters. And I'll shutup for now unless I solve the problem with a Fedora related fix.
Regards,
John
On Thu, 2008-01-31 at 10:30 -0800, John Wendel wrote:
Yes, I split the main cable connection into 2 cables (6-foot to TV, 20-foot to computer) and then split the computer cable into 2 6-foot cables for 2 computers. Have I violated some limit?
As James said, that introduces losses, which may or may not be a problem (signal strength, and the input stages of the devices determine that). You could try one splitter that has four outputs, but then find that the loss in the long cables is just as bad as the loss from the splitters.
Another option is TEE points. Not the same as T-piece connectors that people used with the old BNC LAN cabling (two BNC sockets and one BNC plug, all wired directly together). One signal line goes from the signal source around the premises until the last place you need a feed. Each feed is a TEE that takes a sniff off the cable, in a manner that keeps the lines properly terminated and doesn't attenuate the signal passing through the TEE onto the next one.
That sort of wiring tends to handle having a feed unplugged without disrupting the rest, some splitters don't handle unplugging some of the cables very well.
Termination and cable quality will affect operation, too. Not to mention the quality of the splitters. If your splitters and/or connectors come with guides about how to trim the cable to right lengths for attaching to the terminals, then follow them to the letter.
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James Kosin -
John Wendel -
Tim