Who makes the best coax splitters

[The Boston Dangler]

Originally posted by: alkemyst

It's RG-6 from the pole don't know if quad, but they redid this last year.

:thumbsup:

at 36db s/n, -6 dBmV down and 44bBmV up.

:thumbsup:

IF you aren't passing at least 1GHz through all connections wouldn't HD cable be limited?

most passive gear is rated for 1 GHz, but cable won't use any frequency higher than 860 MHz. the 1 GHz gear came to be with the intention of using it with satellite service. the attenuation at 1 GHz is incredible, so it's not used except for sat tv runs of a hundred feet or so. there is no correlation between frequency and HD/SD content.

 

[mugs]

Originally posted by: alkemyst

Originally posted by: mugs

Originally posted by: Dari
DO NOT put the modem after the cable line has been powered (if you choose to go that route). That will amplify everything, including noise. The ideal solution would be to get a tap (not a splitter) where the one part is losing something like 8dB and the other ports have the same loss.

One excellent brand is Digimax. The ones at the stores are usually garbage.

I have my cable modem after my amp and I have no problem getting up to 20 Mbps...

doesn't mean it always works though.

I don't think there's any harm in increasing the signal and noise proportionately. The signal to noise ratio stays the same. Splitting the line before an amplifier means you're amplifying a weaker signal.

 

[mugs]

Originally posted by: mshan
Cheap initial option would be to just get Monoprice 4:1 and their 2:1 and see if that works ok for you: http://www.monoprice.com/produ...id=2871&seq=1&format=2

Monoprice sells terrible splitters, unfortunately.

 

[Paperdoc]

First of all, you are right to start with a 2-way splitter at the beginning, taking one of these outputs directly to the cable modem. That gives it maximum incoming signal, and minimizes the attenuation of its outgoing signal. Then the other branch goes to all your additional devices.

Now, basically ALL splitters are cascaded chains of 2-way splitters. Every stage reduces the signal by 3.01 dB in an ideal circuit, but in reality I'd estimate it more like 3.3 to 3.5 dB per 2-way split. A 4-way is just like one 2-way, with a second layer of a pair of 2-ways on each output of the first. Put 4 2-ways on each of these and you can make an 8-way.

A 3-way splitter really is a 4-way with one of the first-level outputs not split. So you have one output at 3.5 db down (from 1st splitter level), plus 2 outputs at 7 dB down (from 2nd level).

Likewise, a 5-way is going to have 3 of the 4-way outputs (7 dB down), plus the last of these split 2 ways (10 dB down). But if you got an 8-way splitter system, all 8 would be at the -10dB level.

You can roll your own with a bunch of 2-way splitters and cables bits. Or buy one 2-way and 2 4-ways, and you can make an 8-way.

By the time you get to 8-way you have lost close to 10dB. You can fix that by inserting an amplifier of at least 10 dB gain in the line AFTER the 1st 2-way (where you take off the cable modem line) so that all the TV's have a better signal. The amp goes before any further splitters so the cleanest signal is boosted before splitting. This is such a common need that many places sell combination devices called distribution amplifiers. They combine in one box an amp of 10 to 20 dB gain plus 8 outlets. Usually this is simpler than buying and assembling your own system from individual components.

The only thing missing here, as you suggest, is how to deal with unused outputs. It usually makes only a small difference, but you should get several 75-Ohm terminators. These look just like the screw connector on the end of the coax cable, only with no cable attached. They simply have a 75-Ohm resistor mounted in the center with its wire lead sticking out, just like the center wire coming out of the end of the cable. It screws into an unused output to terminate that line prperly, preventing creation of reflected signals that could disrupt the other lines in the splitter network.

In terms of signal strength, making sure your signal is clean and strong at the beginning of your house system is pobabl;y more important than using low-loss cabling to minimize signal loss. However, bandwidth is another issue. Current cable TV system use frequencies up to about 1000 MHz (1 GHz), so all your components need to handle this. That's cables, splitters, amplifiers. But if you can foresee using satellite signals you should plan for going up to 2 GHz on everything. Some cheaper cables will handle this - sort of. They tend to reduce signal strength selectively at the higher frequencies. The higher-quality cables like RG-6 do not do this nearly as bad.

By the way, don't overdo it as I did. After much troubleshooting in my system I discoverd that I had added 'way too much amplification and the tuners receiving the signals were swamped so badly that they nearly shut down, producing very poor pictures. Removing an excess amp solved the problem.

 

[Paperdoc]

Originally posted by: alkemyst

Originally posted by: mugs

Originally posted by: Dari
DO NOT put the modem after the cable line has been powered (if you choose to go that route). That will amplify everything, including noise. The ideal solution would be to get a tap (not a splitter) where the one part is losing something like 8dB and the other ports have the same loss.

One excellent brand is Digimax. The ones at the stores are usually garbage.

I have my cable modem after my amp and I have no problem getting up to 20 Mbps...

doesn't mean it always works though.

Here's the reason you split off the cable modem line first thing with a 2-way splitter. In the systems I saw, the download portion of the signal is around 750 to 800 MHz. Any decent cable system will handle up to 1000 MHz properly, so the download portion will work anyway, amp or not.

The upload portion, however, is sent by your modem up the cable line at some frequency below 50 MHz - that is, under Channel 2. Now, any amp you insert can introduce a problem. It is a one-way device, boosting incoming signals and forwarding the outputs on to your TV's. But any signal trying to travel backwards cannot get through the amp. For that reason you can buy special amps for this purpose that have a feature called "Passive Return". It is a curcuit that provides a bypass path to allow only signals below 50 MHz to get around the amp and travel back up the line to the cable system's equipment.

However, even a "Passive Return" provides no extra boost to your modem's low-frequency signal. When that signal hits a 2-way splitter it is split into 2 outputs. Even though it is entering the splitter at a port labelled "output", it gets split evenly into the other output and the "input" that is connected to the incoming cable. So now the signal your modem sent out is reduced by 3.5 dB before it leaves your house. If you hook the cable modem behind several splitters, every one of them reduces this low-frequency upload signal on its way back to the cable company. So keep that splitter number low. In other words, put ONE 2-way splitter at the head of the cable entering the house and take one of its outputs directly to your cable modem. The other output from your first splitter can be treated as you want - amps, multi splitters, etc. And since you are not feeding another cable modem from this point on, the amp does not need the "Passive Return" feature.

 

[olds]

Originally posted by: Dari
DO NOT put the modem after the cable line has been powered (if you choose to go that route). That will amplify everything, including noise. The ideal solution would be to get a tap (not a splitter) where the one part is losing something like 8dB and the other ports have the same loss.

One excellent brand is Digimax. The ones at the stores are usually garbage.

They have an awesome web site too.
Digimax

 

[olds]

Bottom line, active splitter before modem or not?

Reading the thread, the answer seems to be no.
But it's working for mugs.

 

[Paperdoc]

Originally posted by: oldsmoboat
Bottom line, active splitter before modem or not?

Reading the thread, the answer seems to be no.
But it's working for mugs.

Bottom line: active splitter (i.e., amp plus splitter(s), or distribution amp in one box) AFTER the single 2-way split that supplies the cable modem. Mugs says it works, but note he / she only quotes download speed. As I said in my earlier post, the amp will actually help the download signal but block or weaken the upload signal.

 

[olds]

Originally posted by: Paperdoc

Originally posted by: oldsmoboat
Bottom line, active splitter before modem or not?

Reading the thread, the answer seems to be no.
But it's working for mugs.

Bottom line: active splitter (i.e., amp plus splitter(s), or distribution amp in one box) AFTER the single 2-way split that supplies the cable modem. Mugs says it works, but note he / she only quotes download speed. As I said in my earlier post, the amp will actually help the download signal but block or weaken the upload signal.

Thank you. :beer:

 

[olds]

One more question.
I need a splitter to send the signal to the modem.
What makes a good, passive splitter? Radio Shack gold for $16.00?

 

[The Boston Dangler]

Originally posted by: oldsmoboat
One more question.
I need a splitter to send the signal to the modem.
What makes a good, passive splitter? Radio Shack gold for $16.00?

no, radio shack is crap. swing by the cable company's office and ask for a splitter. chances are they will have a freebie for you.

 

[MrPickins]

Originally posted by: oldsmoboat

Originally posted by: Paperdoc

Originally posted by: oldsmoboat
Bottom line, active splitter before modem or not?

Reading the thread, the answer seems to be no.
But it's working for mugs.

Bottom line: active splitter (i.e., amp plus splitter(s), or distribution amp in one box) AFTER the single 2-way split that supplies the cable modem. Mugs says it works, but note he / she only quotes download speed. As I said in my earlier post, the amp will actually help the download signal but block or weaken the upload signal.

Thank you. :beer:

They make active splitters that do pass upstream signals, but they tend to be more pricey. I'd go with Paperdoc's suggestion.

 

[axelfox]

I'm also looking to run some more lines to different rooms at my house and this thread is very useful.

If you read the threads and articles from the following links, you'll see that they do not discourage placing the amplifier before the cable modem.

CableTVAmps.com

HTS

DropAmp

 

[Howard]

Originally posted by: boomerang
You should read this.

http://www.swhowto.com/VideoLoss.htm

If you ever forsee the possibility of satellite tv, and you are going to string all new coax, go with RG6 quad shield. The RG6 you have right now may be quad shield.

http://www.bluejeanscable.com/articles/shielding.htm

 

[The Boston Dangler]

Originally posted by: axelfox
I'm also looking to run some more lines to different rooms at my house and this thread is very useful.

If you read the threads and articles from the following links, you'll see that they do not discourage placing the amplifier before the cable modem.

CableTVAmps.com

HTS

DropAmp

i've been a cable engineer for 10 years. go ahead and amp the input of your modem. if it works properly, great. if it doesn't, i told ya so.

 

[axelfox]

Originally posted by: The Boston Dangler

Originally posted by: axelfox
I'm also looking to run some more lines to different rooms at my house and this thread is very useful.

If you read the threads and articles from the following links, you'll see that they do not discourage placing the amplifier before the cable modem.

CableTVAmps.com

HTS

DropAmp

i've been a cable engineer for 10 years. go ahead and amp the input of your modem. if it works properly, great. if it doesn't, i told ya so.

I don't disagree with you (agree more than anything), but just saying that's what they're saying.

 

[Paperdoc]

Originally posted by: axelfox
I'm also looking to run some more lines to different rooms at my house and this thread is very useful.

If you read the threads and articles from the following links, you'll see that they do not discourage placing the amplifier before the cable modem.

CableTVAmps.com

HTS

DropAmp

In reading these carefully, I noted a few things.

First one is informative. It uses the term "Bidirectional Amplifier" for a unit with an amp and several ouput ports that boosts the downloaded signals in the 54-1000 MHz range, and lets the uploaded signals in the 5-42 MHz range pass back up unimpeded. However, that device does not boost anything in the low freq band. It is what I called a "Passive Return" feature. The site notes that "cheapie amps" do not do this and may cause real problems with cable modems or set-top boxes for "Pay per View" and similar interactive functions.

The second, a forum discussion, refers to a particular Radio Shack product, among others, billed as a "Bidirectional Amplifier" with 4 outputs, each at up to 8 dB boosted from the input. Although it says the uploaded signals ar passed, it does not specify the unit's impact on these signals.

The last, operated by Electroline who makes amps, is more detailed. It offers an 8-port amp with each output boosted 4 dB above input, and specifies that the uploaded "Reverse" signal is reduced by 10.5 dB. That is exactly what you get from 3 levels of 2-way splitters at 3.5 dB each level. The site also recommends specifically for houses with cable modems a different model with "Active Return", and says this one sends the uploaded signal back out with no reduced signal. It appears they have built in (I suspect between the main amp and the splitter network) a bandpass amp of 10 dB gain for the 5-42 MHz range that sends its output around the main amp back up to the cable company. This is ideal for any place that has more than one cable modem. The only issue would be that the 10.5 dB loss in the splitter network happens before the 10 dB offsetting gain, so the final signal has just slightly more noise in it. However, I'm sure that is not important.

By comparison, my suggestion was to put a single 2-way splitter first, taking one output to the cable modem and the other to the simple distribution amp for all other TV's. This way would send back up the line a slightly less noisy signal, but it would be weaker as it leaves the house.

 

[dartworth]

Here is what I did...


http://www.avsforum.com/avs-vb/showthread.php?t=1050643

 

[axelfox]

Originally posted by: Paperdoc

Originally posted by: axelfox
I'm also looking to run some more lines to different rooms at my house and this thread is very useful.

If you read the threads and articles from the following links, you'll see that they do not discourage placing the amplifier before the cable modem.

CableTVAmps.com

HTS

DropAmp

In reading these carefully, I noted a few things.

First one is informative. It uses the term "Bidirectional Amplifier" for a unit with an amp and several ouput ports that boosts the downloaded signals in the 54-1000 MHz range, and lets the uploaded signals in the 5-42 MHz range pass back up unimpeded. However, that device does not boost anything in the low freq band. It is what I called a "Passive Return" feature. The site notes that "cheapie amps" do not do this and may cause real problems with cable modems or set-top boxes for "Pay per View" and similar interactive functions.

The second, a forum discussion, refers to a particular Radio Shack product, among others, billed as a "Bidirectional Amplifier" with 4 outputs, each at up to 8 dB boosted from the input. Although it says the uploaded signals ar passed, it does not specify the unit's impact on these signals.

The last, operated by Electroline who makes amps, is more detailed. It offers an 8-port amp with each output boosted 4 dB above input, and specifies that the uploaded "Reverse" signal is reduced by 10.5 dB. That is exactly what you get from 3 levels of 2-way splitters at 3.5 dB each level. The site also recommends specifically for houses with cable modems a different model with "Active Return", and says this one sends the uploaded signal back out with no reduced signal. It appears they have built in (I suspect between the main amp and the splitter network) a bandpass amp of 10 dB gain for the 5-42 MHz range that sends its output around the main amp back up to the cable company. This is ideal for any place that has more than one cable modem. The only issue would be that the 10.5 dB loss in the splitter network happens before the 10 dB offsetting gain, so the final signal has just slightly more noise in it. However, I'm sure that is not important.

By comparison, my suggestion was to put a single 2-way splitter first, taking one output to the cable modem and the other to the simple distribution amp for all other TV's. This way would send back up the line a slightly less noisy signal, but it would be weaker as it leaves the house.

Thanks for the insight.

I'm looking to run some RG6 cables to some of the other rooms in my house. It's an 1970s 2 story house with an attic, but all of the existing runs pretty much are on the outside.

I've attached a link to a diagram for the proposed setup The arrows indicate existing cable runs, but not with the splitters as diagrammed in the image.

Proposed Cable Run

The cable line will run into the house where it will be split from the cable modem. It runs into the house first because there is no other power outlet where I can place the amplifer after splitting it off to the cable modem. The other line will be hooked into a powered drop amp and then split 2 ways, with one line being sent back outside to hook up the other rooms.

The inside line will split 3 ways and run to the TV room, Kitchen, and Bedroom 5.

The outside line will run into a 4 way splitter to the living room, Bedroom 3, and two 2-way splitters, with one line going towards the Patio and Bedroom 5 (shared wall), where it will be split again to provide an outlet for those two rooms. The other line will go to a splitter near the Master Bedroom and Bedroom 2, where it will be split for those two rooms.

Alternatively (not in the diagram), I could have a 4 port powered drop amp and connect the TV room, kitchen, and Bedroom 4 directly to the powered drop amp and run the other line outside with the same outside setup.

Hopefully it's not too confusing. Thanks for the help.

 

[mugs]

Originally posted by: Paperdoc

Originally posted by: oldsmoboat
Bottom line, active splitter before modem or not?

Reading the thread, the answer seems to be no.
But it's working for mugs.

Bottom line: active splitter (i.e., amp plus splitter(s), or distribution amp in one box) AFTER the single 2-way split that supplies the cable modem. Mugs says it works, but note he / she only quotes download speed. As I said in my earlier post, the amp will actually help the download signal but block or weaken the upload signal.

Mine reduces the upstream signal by 1 dB. Not the end of the world.

You're going to be able to tell if you have a problem either way. My problem at my old house was that I couldn't pick up all of my cable company's clear-QAM channels, so I wanted to make sure I had the best possible signal to my TVs.

You know, your cable box is essentially a different type of cable modem. It receives the same type of signal (QAM), demodulates it, and turns it into audio and video. The cable modem receives a QAM signal, demodulates it, and sends the result to your router or computer. Many cable boxes are two-way as well. Anything that negatively affects your cable modem would negatively affect your cable box in the same way.

 

[Paperdoc]

To Axelfox:
Can't get a look at your diagram from where I am, but the description seems clear. First items in network are a 2-way split (1 to modem, 1 to amp), a drop amp, then a 2-way split (one outside, one inside). So far we have 7 dB loss in 2 levels of splitters, offset by whatever the amp does. The modem's signal will always be 3.5 dB down from incoming signal no matter what the amp does, and that should be fine.

The inside line should go to a 4-way splitter (further 7 dB loss) with one output terminated and the other 3 to TV's. The greater challenge is in the outside line. It gets a 4-way (7 dB loss) to feed two TV's, but additional 2-way (3 dB) on two of the lines. So these last four TV's (Patio, BR5, Master BR and BR2) are now 10 db lower than the start of the outside line, or 13 dB below the amp output, or 17 dB below the cable signal coming into the house. For this you should have a drop amp with at least a 15 dB gain, and maybe 20 dB.

However, then we look at the effect on the first inside line. Its losses, starting from incoming cable, were 7 dB up to the the output of the second 2-way splitter, plus 7 dB from the 4-way, total 14 dB. A 15 dB amp would balance this out nicely; a 20 dB amp would be more than necessary, and carries the slight risk of overdriving the TV's on the inside line, but might be just fine. If you look closely at the "outside line", two of its TV's also are directly on a 4-way and get the same signal strength as the ones on the "indor line". On balance, a 15 dB amp will give you good performance, with a slightly weaker signal at the 4 TV's on the furthest ends of the network, but probably OK. A 20 dB amp would give you all you need, but just might overdrive the three "inside line" TV's and maybe two on the "outside line".

There is one possible glitch in this, and that is the length of the "outside line" run. Even though you upgrade the cable, you might see more signal loss there than on the "inside line" branch. If that shows up, you could consider this: design originally with one 15-dB Drop Amp, which should give good signals everywhere except MAYBE at the last 4. Then, if the last 4 or all of the "outside line" units seem a bit noisy in the picture, you could add a small additional drop amp able to do 3 to 6 dB (no more than 10) between the second 2-way splitter and the "outside line". That way only that line gets the extra boost, and you don't even do that unless your first design shows it is needed.

 

[olds]

I was double checking my cables to verity that they are RG6 before I changed some runs.
The cable is not marked RG6. They are marked BW3912241 2007 9900963 CM c (ETL) US or CATV (ETL) US 18 AWG
I get the 18 average wire gauge and google seems to say that BW is Bright Wire but I turned up nothing definitive. Anyone know what this cable is?
TIA

 

[olds]

Anyone?

 

[ScottMac]

Originally posted by: oldsmoboat
One more question.
I need a splitter to send the signal to the modem.
What makes a good, passive splitter? Radio Shack gold for $16.00?

Holland makes the best passives and diplexers. The best there is, and at normal prices.

 

[PlatinumGold]

just in case any of you guys get FIOS.


fios requires bandwidth from 5 to about 1500 hertz. the range above 1000 hertz is used for guide info, vod and the mrdvr feature. so if you are thinking there is a chance you will get fios in the near future, get splitters that allow for frequencies up to 1500 hertz.