splicing a spliced cable line

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I have a three way splice from the cable company, and would like to splice it yet again for a fourth television. Should I go out and buy a 4-way splice, or can I just hook a two-way on to an existing run?
Does anyone know what the biggest splice I can use is before i start to lose signal quality to a noticable level? We're not too picky about signal as we don't have Hi-definition or anything, but it's still gotta be watchable.
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You don't splice cable line. You connect separate pieces using the connectors. If you need to SPLIT one, you use a splitter box.
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Two-way splitters cause a 3 dB loss (the power is cut in half for each circuit ... actually it is a little more since splitters are not perfect). Ganging splitters adds another 3 dB loss for each 1 to two split. Some cable companies provide a rather robust signal and multiple splitting (within reason) is not a problem. Others provide a marginal signal and even one splitter shows up as a noisy signal (grainy looking picture). Splitters are cheap ... just go ahead and try it.
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Do I lose more by buying one 8-way splitter than using a two-way splitter? Or is it the same 3db loss between all these?
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A 2-way splitter approximately cuts the signal in half, a 3-way will give each output 1/3 of the power, etc. However, if you have an 8-way splitter, but only have 3 cables coming out of it, I'm not sure if each cable gets 1/3 or 1/8 the power (since you only have 3 "circuits").

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Unless the other 5 outs are functioning as antennas(!) -- and they cannot be, since the wavelength is much longer than they are, you divide by 3 -- ie, only 3 loads.
David
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David Combs wrote:

Ideally you have to terminate the unused connector with terminating plug (50 Ohm non-inductive resistor). You can buy them from RS for minimal cost. I won't go into detailed theory for that.
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No way Thats like saying since I have three 120v outlets on one line so each outlet is now 40v singal loss yes 1/2 or 1/3 no way does not work that way I have a two way splitter sitting right here one outlet is marked 7db the other is 3.5 db So even each outlet may not have the same loss My OTA singal went from 90 to 88-89 Spud
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wrote:

It is no way like that.
A typical 2 way splitter has 3db or more loss on each output from the input. A 3db loss means that the power at the output is 1/2 the power at the input. Every 3db loss cuts the resulting power in half again.
http://www.swhowto.com/VideoLoss.htm
Bob
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As far as I know, the difference is small (with quality splitters).
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Thanks guys, I'll go ahead and get an 8-way and give it a try. Can I use the crimp type connectors without a special tool? I'm seeing "compression type" which our cable company uses, and I don't ahve one of those tools. I do have a simple solderless-terminal crimper that may work to crimp type connectors.
Do they make one that works better than the crimp type, like one that I can just screw together or something, there won't be much opportunity to pull on these lines as they'll be in the wall.
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The solderless terminal crimper will not work correctly, although you lose nothing but an inch of cable to prove this to yourself. Go buy the right tool to do the job the way the cable company did it.
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By the way, Home Depot carries the right tool. Not expensive.
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" snipped-for-privacy@gmail.com" wrote:

Do *not* get a splitter with more ports than you need. Every split (one to two) looses 3.5db of signal to each output port whether you have something connected or not.
There is commonly only a one to two splitter, so every larger splitter is just a collection of two way splits internally.
Splitter losses:
2 way = two 3.5db loss ports
3 way = two 7db loss ports and one 3.5db loss port
4 way = four 7db loss ports
8 way = eight 14db loss ports
Unused ports should be terminated with 75ohm terminators. Open ports are a source of both signal leakage which can interfere with over the air signals including police radios and air traffic control, and also ingress where these over the air signals can get into the cable and interfere with the cable signal. Cable companies are required to periodically survey their entire systems and certify compliance with maximum leakage limits imposed by the FCC.
Improperly connections such as twist on or set screw F connectors or improperly done crimp or compression F connectors will also cause problems. These connections are more sensitive than most people think, and they are only becoming more sensitive as cable systems expand to higher frequencies.
There is also signal strength loss from every connector, ground block, etc. in the system (insertion loss) and loss from every foot of coax cable. Don't have any more connections than you need or any large excess of cable in your setup if you want the best signal.
The total signal loss is important in the "forward" direction (from the cable Co. to you) and even more important in the "reverse" direction (from you to the cable Co.) if you use things like a cable modem or pay per view from a two way cable box.
Pete C. (Used to work for Cox cable)
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"Pete C." wrote:

Forgot to mention:
You also need to make sure the splitters you use are rated for the frequencies in use in the cable system. These days it's safest to assume systems are up to 1GHz so you need a 1GHz rated splitter. An old 750MHz rated splitter will work for some channels, but you will loose others that are at higher frequencies because the splitter can't handle them without substantial attenuation.
Cheap splitters also have poor shielding which can cause leakage and ingress problems. The shielding rating is usually stamped on the back of the splitter, 140db is a typical good value for this, less typically means it's a cheap splitter.
Pete C.
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wrote:

It's best to only split once. Find where the cable is initially split where it enters the house and replace the three way with a four way. Downside is that it means running a cable all the way from the cable box to the new TV. There are also some cheap amplified splitters. I had good results with an RCA amplified splitter I got from home depot.
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On Wed, 29 Nov 2006 22:17:27 GMT, AZ Nomad

I'd be better to keep the amplifier separate, so you get to use only what you need. A too-strong signal is as bad as a too-weak one.
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wrote:

Agreed, although that cheapo RCA didn't seem to overamplify. If you go with an amplified splitter, it should be a close to the cable box as possible. If you've lost your signal by running splitter after splitter, using an amplifier won't recover your signal from the noise.
I had a multimedia computer with 3 video inputs (three capture cards); add to that a VCR and TVs in three other rooms and I had 7 devices that needed a signal. I ran a three way splitter at the cable box, and then two runs each to a four way amplified splitter. The third run went to a cable modem.
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On Thu, 30 Nov 2006 01:26:58 GMT, AZ Nomad

Right. The amplifier needs to be connected at a point BEFORE the signal loss occurs. That is, before the splitters.

A cable modem (and/or digital cable box) are best connected before any amplifiers (and with minimum splitters) because these devices also send signals to the cable office.
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On Wed, 29 Nov 2006 18:33:20 -0600, Mark Lloyd

My smaller amp has only one output (or two?)
The next size bigger has 2 outputs plus a adjustment for output strength.
I think I have it set all the way up, but you're definitlely right about a too-strong signal. In order to get DC stations in Baltimore, I have an amplified (RAdio Shack) antenna in the attic. Once in a while for a Baltimore station (11 I think is the only one) the signal is too strong, so I put in an A-B switch to switch from the amplified antenna to nothing. The one foot cable from the VCR to the A-B switch functions as the antenna, and even though it is coaxial and shielded, it gives a good picture for channel 11, the only one I use it for.
I may have to get a remote-controlled A-B switch if I get in the habit of changing to and from channel 11 from the other room. (Although this is only a problem sometimes.)
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