cable tv spliter, who know if a higher or lower dB is better?!

[BillyBatson]

I am splitting my cable tv to my TV set and to my winTV card on in my PC but once i sp;lit it the quality both on my tv and viewing tv on my comp drops greatly. I am using a Monster Cable splitter tthat does 3.5dB out to each out. I have another audiosomethign splitter that does the same 3.5dB out to each out, but then i have a Philips spliter that does 3.7dB to each out.

Which would be better 3.5dB or 3.7dB to split the signal? is a higher or lower dB better??

 

[Sphexi]

Lower is better, that's the loss per conecction. If you have one of the spots you're not using, cap it with a terminating resistor to prevent loss through it. Otherwise try an amp before the splitter to pick the signal up.

 

[Evadman]

-3.5 is basicly standard.

Say you have a +7db signal. A standard splitter will drop that by 3.5 for each split. 3db is exactly half strength, which means you split the signal, you split the power, plus loose about 1/6th in the split. so you end up with about +3.5 on each channel.

 

[BillyBatson]

damn this sucks lol i didn't realize it would make such a big impact. I have a straight independant line running to the cable modem but then i have a cable line running to the living room which is split to 4 diff rooms with 4 diff tv's (including 1 for mine) and that ws the line i was trying to split again.

If i bought an amp going to the first splitter than another right before my spliter, that should fix the problem?

 

[Evadman]

Originally posted by: BillyBatson
damn this sucks lol i didn't realize it would make such a big impact. I have a straight independant line running to the cable modem but then i have a cable line running to the living room which is split to 4 diff rooms with 4 diff tv's (including 1 for mine) and that ws the line i was trying to split again.

If i bought an amp going to the first splitter than another right before my spliter, that should fix the problem?

In other words, the signal you will get on that last line is roughly 8% of the signal strength coming in. Ouch. Just remember, boosing a crappy signal just gets you more crap. Make sure all the splitters are at least 1 GHZ (usually listed as 5-1000 mhz) and only install a booster if you need it, and it goes BEFORE any of the splitters. In addition, a 8 way splitter will loose less than two 4 ways.

Check your documentation to see what is the acceptable DB range for whatever you are putting into it. IIRC the strength at the side of the house must be at least 15 DB, but can go from 0- 25. (zero does not mean zero strength, just zero DB). Negitive values are possible, and supported my most recievers. Optimum for a TV IIRC is 8-15. But some recievers will go to -15 to 25 DB.

<Oldsmoboat>
Added a parenthesis for Evad.

 

[RaynorWolfcastle]

Evadman is correct. You can add an amplifier (before the splitter, obviously) if you're really having problems. You should put your amp as far up in the stream as you can since you want to amplify the cleanest signal possible and each split both weakens the signal and adds noise.

 

[iwearnosox]

Modern cable company splitters use a -3.5db out for the modem and -7db for tv. If you have a cable modem this is the type you should use.

 

[BillyBatson]

what sort of amps do you guys recommend? so far i found this and how does it work if ther e is no external power source?


edit

i also found these

this and this

 

[Kelemvor]

On standard non-HD TVs you won't notice a huge difference most of the time...

Here's the setup in my house.

Cable line in from outside
Hits 2 way splitter to go up to cable modem - main line continues
Hits a 3 or 4 way splitter to go to bedrooms and family room - main line continues
Hits another 3 or so way splitter to go off to the basement rooms and such.

All of them work fine. I did have trouble when my digital box was coming off the last splitter so we moved it to come off the middle splitter and it seemed to help. But even the basement TV on the far end of everything only has a slightly dirty looking picture.

I wouldn't worry about an Amp until you try it without and see if you have problems.

 

[Tifababy]

I was having signal issues with my HD cable box, and being the geek I am, I interrigated the cable technician. He told me that in our area, all houses were guaranteed 10dB coming into the house. I asked him what strength the HD box needed and he said that their rule of thumb is for HD boxes they want the strength >1dB, but it will still work as long as it's above 0dB. For analog cable, they don't get concerned until you reach below -3dB. I was also told that if you have a digital cable box or HD cable box that they don't like you to add an amplifier because most cheap amplifiers are one way, so the boxes cannot send data back to the cable company which is needed for diagnostics if you call in complaining about poor service. So instead of using an amplifier, I called the cable company and they came out and put in all new splitters and higher quality connectors on all the cable tv lines in my house...for free!

 

[BillyBatson]

FrankyJunior thanks for the info, i am having problems however the quality on y tv set dropped to where i notice it and of course my htpc is recornding the same lower quality.

Tifababy, for free you say? haha. I might try that thought i think i am going to buy a nicer splitter today for the living room which splits 4 ways, it is REALLY old and it is 0-900mhz and it doesn't say what the -dB out is for each line out.

I also found out that one of hte line outs in the living room was going to yet another splitter that was -4dB out to each line! and then to my sisters tv so that was removed (and thrown away) and she got connected directly to 4 way and her tv now looks nicer.

thanks for the help everyone!

 

[TechnoKid]

I'd reccomend replacing the four way splitter you have now with a amped four way, or, a two way amp, and then a four way off of that and another spliter for your needs.

http://www.dslreports.com/faq/cabletech read that

and here is the splitter i'd reccomend: Electroline four-port amp

Electroline two-port amp


street>twoway split>cable modem/four-port amp>tvs/your split
street>twoway split>cable modem/two-port amp>fourway split/addt'l split

Your cable modem needs to be run off of one of the legs from the first two-way split, thats how its setup now i presume. Then on the other leg, you can run one of the setups mentioned above, either a two port amp into splitters, or a four port amp into splitters. I suppose you could go with a higher port amp, but, you'll get greater insertion loss per leg. You do not want to re-amp an already amped signal unless you use a unity gain 'amp'.

Also make sure all your connections are using crimped connectors or compression (ala thomas and betts SNS) connectors and NOT screw on connectors. Are all your cabling RG6? If not, replace all cabling with RG6 or RG6QS (quad shiled).