Hi there! I just got a new LCD HDTV with a QAM tuner, so now I'm thinking I'm going to need a 3-way splitter. Before, I just used a 2 way splitter for my Internet and to my non-digital cable box, but now with my QAM capable HDTV, I'm thinking I'm going to need a 3 way splitter to make use of the QAM. Now, my question is will splitting a connection into 3 different sources weaken it at all? For example, am I going to be experiencing any extra slowdown in my Internet, or not pick up enough channels through the QAM since it is from a 3-way split signal?

Anyways, does anyone have any recommendations on a 3-way splitter to buy, or will any regular store bought splitter do fine? Should I look for anything special like something that's gold plated or whatnot?

I know it's a lot of questions, but thanks to all those who answer.

A 2-way is -3.5dB on each leg.
A 3-way generally has -3.5dB on one and -7dB on the other two.

Use the -3.5 output for cable modem and the other two for video. If there is too much of a signal degradation, call you cable provider to check/adjust levels.

Would it be better if I just buy another 2 way splitter, and split one of the connections coming out of the original splitter? Or would that be less efficient?

Makes no difference.
Once you add another 2-way, the power is halved and becomes -7 on each leg. It's better to use a three-way IMO. One less cable in between. ;)

Cool, thanks alot! BTW, can I just buy any regular 3-way splitter, or should I look for something with certain details like being gold plated or something?

IMO... any three-way will be fine.
Look for 5-1000MHz and bidirectional. Gold plating is just a color.
best to look at the "specs" on the existing splitter and get a 3-way that matches.

Cool, thank you again! You've been a big help!

agree w/ratman

hook it up like he said and if you have issues, call your cable co to test.

i had issues after my cable modem install since we have 4 tv's and cable modem.

comcast had to come & re-run the wires as they were vintage cable wires. no not all cable wires are equal.

you want your most "important" leg to have the least amount of splits. my cable modem is them most direct, followed by the DVR and then the other analog tv's.

IMO... any three-way will be fine.
Look for 5-1000MHz and bidirectional. Gold plating is just a color.
best to look at the "specs" on the existing splitter and get a 3-way that matches.

Stay away from gold plated splitters, You want to use common metals in the system, Having uncommon metals can cause a CPD issue. As for any 3 way working you want the 5 - 1000 as alisted above and best best is to used a balanced 3 way, This will have a forward loss of 5.5dbmv and the same for return gain on each leg.

Having uncommon metals can cause a CPD issue

What is a CPD issue?

This will have a forward loss of 5.5dbmv and the same for return gain on each leg.

I understand what happens in the forward (splitting) direction but what do you mean about the return gain?

What is a CPD issue?

Common Path Distortions

"It is a result of a combination of undesired processes that take place at such passive junctions and normally come into play after some incubation period during which a non-ohmic metal oxide cell is setup. This is commonly referred to as the Diode or Bimetallic effect. Of these the Diode effect is probably the most appropriate generalised description. An ohmic device is one which has a linear I-V characteristic such as a resistor and a non-ohmic device has a nonlinear or asymmetric response such as that of a diode curve. Such non-linearities at contact surfaces give rise to CPD.

In microscopic terms connector surfaces have irregularities and numerous crevices. Such crevices are largely present on the threads of F-connectors here the peaks and troughs often have sharp edges. Any coating at such points is easily damaged by the mere action of threading on a connector. Threads are often left with rough edges where corrosion can start easily. Added to that the protective metal coatings on many connectors are insufficient and of the order of 2-3 microns only. Any superficial damage to this coating reveals the base metal which in presence of moisture and other corrosive materials accelerate the process. This is accelerated further by the changes in ambient temperature which promote ‘breathing’ through the minute gaps between the threads. Moisture in the air will tend to get trapped in the crevices from where evaporation is difficult. Corrosion cells thus set up
accelerate the bimetallic effect." [Author unknown]

Good to see smooth_imports make mention of it.

Couldn't have cut and pasted better myself. ;)
http://cable.doit.wisc.edu/cpd/cpd2.html

As for the return path... I always thought that the loss on the "return" path when using a bi-directional splitter is nominal.

The loss of the return path (when combining) through a power divider/combiner is the insertion loss of the device.

Couldn't have cut and pasted better myself. ;)
http://cable.doit.wisc.edu/cpd/cpd2.html

As for the return path... I always thought that the loss on the "return" path when using a bi-directional splitter is nominal.
I didn't know that Dave had put it on his website. I have had a copy of it for a few years. It is an excellent article.

The loss going through a passive device is pretty much the same regardless of forward or return. The lower frequencies have a slightly lower loss, but only a few tenths of a dB.

The loss going through a passive device is pretty much the same regardless of forward or return.

Are you really sure?

It is always rude, and usually illegal to distribute someone else's work without at least giving them credit.( Is Dave still working.) :)

Alright, three way run-down, in one concise post. :D

They can be balanced or unbalanced. Balanced loss is about 6.7 dB. Un-balanced loss is about 7.9 dB and about 4.1 dB on the low loss leg. Loss is the same either direction, about .5 dB less at return frequencies.

For cable 5-1000 MHz bandwidth is sufficient.

The best way to tell a quality splitter is to turn it over, is the back pressed, glued or soldered to the housing? Soldered is the best. Color is not important. Keep connections tight and dry, best defense against CPD and other problems.

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Need a splitter with DC power pass, esp. if you have cable box in line. Recommend something going up to at least 40-2150 mhz. That what we use at work when we are redoing distribution panels.


SAY WHAT? :eek:

DC Power pass would only be necessary if you are feed power to an amp through the coax. I would suggest this be avoided at all costs. Too easy to get AC hum on the line. No cable box that I know of requires a DC path.

40-2150 MHz? Might as well use your cablebox and cable modem as door stops. Without 5-40 MHz that's about all they will be good for.

Wow, just wow. :eek::confused:

SAY WHAT? :eek:

DC Power pass would only be necessary if you are feed power to an amp through the coax. I would suggest this be avoided at all costs. Too easy to get AC hum on the line. No cable box that I know of requires a DC path.

40-2150 MHz? Might as well use your cablebox and cable modem as door stops. Without 5-40 MHz that's about all they will be good for.

Wow, just wow. :eek::confused:
C'mon -- everyone needs a good laugh every now and then.

For cable, definitely no need to go up to 2150MHz and a definite need to go down to 5MHz.

.

I actually mistyped, agreeing that the splitter should be down to 5, but you guys can laugh all you want. Your lab tests tell you that you dont need DC Power pass or passthrough to 2150, but I am telling you what works in real world experience, redoing Comcast screwups in clients homes every day. Most of the homes we work in are large enough to require an amp, thereby necessitating the DC power pass.


Oh, mistypes, I see. :rolleyes:

Ya, I guess B O X is pretty close to A M P. :rolleyes:

Ya, I fat finger 4 0 when I mean 5, ya, all the time. :rolleyes:

:D

There is NO reason whatsoever to have AC running thru any cable OR splitter...If you have so many outlets that a house amp is required then the house amp has its own dedicated power source...usually a wall transformer...and BLOCKS ALL AC/DC on the output...Put AC thru the output and you WILL fry a STB or a television tuner at a minimum...

If XM2GO is using satellite splitters as he stated:Need a splitter with DC power pass, esp. if you have cable box in line. Recommend something going up to at least 40-2150 mhz. That what we use at work when we are redoing distribution panels.he is converting cable homes to satellite homes because those splitters WILL NOT pass the reverse in ANY cable system...and there would be many upset customers if he was knocing out their internet & phones...;)

I actually mistyped, agreeing that the splitter should be down to 5, but you guys can laugh all you want. Your lab tests tell you that you dont need DC Power pass or passthrough to 2150, but I am telling you what works in real world experience, redoing Comcast screwups in clients homes every day. Most of the homes we work in are large enough to require an amp, thereby necessitating the DC power pass.
Lab tests???

Design says there there should be a signal strength of 10-15 or 15-20dBmV at the tap (depending on system design), and real world says there usually is. If not, the issue in the outside plant that is causing the low signal needs to be resolved. Just throwing an amp in at the customer's house merely Band-Aids the problem, and when the outside plant is restored to what it should be, that Band-Aid itself may very well cause problems for that customer.

With 15dBmV at the tap and the house being, say 50' back from the road, there would be a signal level of (15-3.1(50' of RG 6)=) 11.9dBmV at the groundblock. Enough for 3 TVs and a cable modem with no additional amplification. More than that and yes, there is going to be additional amplification needed. A standard 15dB gain drop amp is plenty for most houses.

Power passing splitters are absolutely not needed in most cases as there is no power to pass to anything. The only exception would be if there is no a.c. where the amplifier is located and it must be powered remotely. Even then, only 1 leg of the splitter needs to pass power.

Cable systems in the U.S. are up to 750MHz. Some are 860MHz, and there are even a few 1000MHz ones, so why would splitters that go up to 2150MHz be needed? The insertion loss at the bandwidth used (5-1000MHz) is greater than splitters by the CATV industry. Why would you want to use splitters that lose more signal.

Throw into the mix that when (if) they go with a satellite provider, that splitter will get replaced with a multiswitch.

On second thought...

Marketing, marketing, marketing.

Tell the customer that it is made for satellite and they will think it is better than what is made for cable TV. Tell them that it goes all the way up to 2150MHz and the ones made for cable ONLY go up to 1000MHz. BAM -- it's a better splitter. Tell them that it passes power whereas the cable one doesn't, and it's an even better splitter. Don't forget to mention that it's GOLD PLATED, and they'll buy it for anywhere from 15-25 bux rather than get one that's more efficient for less than 6 dollars.

No wonder Comcast gets a bad rap... subcontractors that don't have a lot of technical experience. ;)

Lab tests???

Design says there there should be a signal strength of 15-20dBmV at the tap, and real world says there usually is. If not, the issue in the outside plant that is causing the low signal needs to be resolved. Just throwing an amp in at the customer's house merely Band-Aids the problem, and when the outside plant is restored to what it should be, that Band-Aid itself may very well cause problems for that customer.

With 15dBmV at the tap and the house being, say 50' back from the road, there would be a signal level of (15-3.1(50' of RG 6)=) 11.9dBmV at the groundblock. Enough for 3 TVs and a cable modem with no additional amplification. More than that and yes, there is going to be additional amplification needed. A standard 15dB gain drop amp is plenty for most houses.

Power passing splitters are absolutely not needed in most cases as there is no power to pass to anything. The only exception would be if there is no a.c. where the amplifier is located and it must be powered remotely. Even then, only 1 leg of the splitter needs to pass power.

Cable systems in the U.S. are up to 750MHz. Some are 860MHz, and there are even a few 1000MHz ones, so why would splitters that go up to 2150MHz be needed? The insertion loss at the bandwidth used (5-1000MHz) is greater than splitters by the CATV industry. Why would you want to use splitters that lose more signal.

Throw into the mix that when (if) they go with a satellite provider, that splitter will get replaced with a multiswitch.

On second thought...

Marketing, marketing, marketing.

Tell the customer that it is made for satellite and they will think it is better than what is made for cable TV. Tell them that it goes all the way up to 2150MHz and the ones made for cable ONLY go up to 1000MHz. BAM -- it's a better splitter. Tell them that it passes power whereas the cable one doesn't, and it's an even better splitter. Don't forget to mention that it's GOLD PLATED, and they'll buy it for anywhere from 15-25 bux rather than get one that's more efficient for less than 6 dollars.

Nicely put.

I only wish our cable system was designed like that, and had that much signal out of the tap (15-20db). I've seen it like that in a lot of MDU areas, but mostly see 10-15db for single family homes, unless it's a hot tap needed for a long drop.

The setup that "XM2G0" is referring to is definitly for a satellite system only. I worked for Dish Network for 10 months (hated it), and you have to supply power to the LNBs from the receivers thru the coax cables to make the system work. Which means that all passive devices must pass power, if it's in the path between the LNB and the receiver.

If you apply that same setup with cable, the cable companies would go bankrupt because all of their modems and set top boxes would be fried, not to mention all the damage claims from customers who had their HDTV's, etc. fried as well.

As far as what types of splitters to use, if I see any splitter that is not a cable company approved splitter, then it gets replaced.

- Cable Tech

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Further more, we are only subcontractors for Comcast, because their team of wonderful installers come in after our custom installations, and messes everything up. Also, all of our installations have boxes. We NEVER connect TV's straight to basic cable (no STB) or straight antenna. We have done this, but only old analog TV's or antenna as a backup for Satellite weather fade.

Well you sure as heck do not work for Comcast if you are doing back-up connections of antennas for satellite weather fade...

So what are you saying...That you go in and custom install...then Comcast comes in and messes everything up...then you have to go back and clean up after Comcast??? Yet you are charged back $189.00 for any customer service call??? Which is it??? If you did a custom install and Comcast comes out after you...that is a service call...You make no sense...Especially if you are a sub for Comcast ALL your materials come from Comcast and they DO NOT use 40Hz-2150MHz splitters for their CATV system in Chicago...THAT is "real world" knowledge...:rolleyes:

Come back after you learn the difference between satellite and cable installations...It is people like you that has destroyed my industry...:mad:

Well you sure as heck do not work for Comcast if you are doing back-up connections of antennas for satellite weather fade...

So what are you saying...That you go in and custom install...then Comcast comes in and messes everything up...then you have to go back and clean up after Comcast??? Yet you are charged back $189.00 for any customer service call??? Which is it??? If you did a custom install and Comcast comes out after you...that is a service call...You make no sense...Especially if you are a sub for Comcast ALL your materials come from Comcast and they DO NOT use 40Hz-2150MHz splitters for their CATV system in Chicago...THAT is "real world" knowledge...:rolleyes:

Come back after you learn the difference between satellite and cable installations...It is people like you that has destroyed my industry...:mad:

=Sigh=

=Sigh=

Exactly...:rolleyes:

20 bucks for a splitter!

Surely this guy works for Monster. :)

Well you sure as heck do not work for Comcast if you are doing back-up connections of antennas for satellite weather fade...

So what are you saying...That you go in and custom install...then Comcast comes in and messes everything up...then you have to go back and clean up after Comcast??? Yet you are charged back $189.00 for any customer service call??? Which is it??? If you did a custom install and Comcast comes out after you...that is a service call...You make no sense...Especially if you are a sub for Comcast ALL your materials come from Comcast and they DO NOT use 40Hz-2150MHz splitters for their CATV system in Chicago...THAT is "real world" knowledge...:rolleyes:

Come back after you learn the difference between satellite and cable installations...It is people like you that has destroyed my industry...:mad:

Nicely put as well.

I've been a field tech now for cable in the "real world" for almost 7 years (compared to XM2G0's 2 years). We have contractors that work for us, and they do not do "custom" installs. They do the same type of installs that in-house techs do, and are only called to help when the work load is heavy and our scheduled appointments are pushed out over a week (which is almost all the time).

The stock that the contractors use comes from the same warehouse that us "techs" get our stock from, which means there are no splitters rated 40 - 2150 mhz (like I used when I was with Dish Network), only 5 - 1000 mhz splitters are used. Without the 19 - 37.50 mhz range on the splitters, our modems would never work. So yes, us "techs" would have to "mess up" the "custom" install if "those" splitters were used in our system, because it would be setup WRONG.

If you noticed the last comments made by XM2G0, it was said that they never connect the coax straight to the TV, and that they always have a box to install. That sounds like satellite to me, especially where it's mentioned about weather fade. Cable has no issues with weather fade, only satellite does.

Ok. I'm done with this battle. :cool:

- Cable Tech

I cannot agree with what you guys are posting. I understand the technical points you are making, however, I live in the real world of custom installation. Serving customer is my top priority, hence why I ever posted a response the the original 3 way splitter question. In reality, buy any quality 3 way splitter for around 20 bucks and you should be fine. If you are that concerned about signal loss, by pass the splitter and run a straight feed.

As I see that this thread will has turned into nothing short of a pissing match...
No pissing match here -- just a bunch of guys with a combined several decades of real world experience in cable TV.

You wrote that what was needed were 2GHz splitters with no return path. They also needed a path for power. You subsequently conceded that there does, in fact, need to be a return path. Why the insistence that there needs to be a path for power when there is no power involved, or a bandwidth of 2GHz when the system's bandwidth tops out at no more than 1GHz is difficult to understand. Not just difficult to understand -- it makes no sense.

Nobody is saying that you haven't straightened out messes at clients' homes. Unfortunately, messes happen all the time and someone has to straighten them out.

If someone tells you that a certain something (whatever it may be) shouldn't be done a particular way, that may be just their own, personal opinion based on their way of doing things. It may or may not be based on anything factual. If several different people tell you the same thing, odds are pretty high that there is merit to what they are saying. Do some research into the subject rather than insist that what is being questioned (challenged) is right just because the boss says so.

Don't leave this or any other forum just because someone may challenge something you may write. Heck, I got jumped on because I quoted something someone else had written in a report a few years back without giving proper credit. (My copy did not come from the website posted). We're all here to share information and experiences.

(You can go on the Web and buy a 3-way splitter made by a major CATV industry manufacturer for well under 20 bucks. Less than 10 even.)(Not eBay, either.)

HFC-systems will never go above 1-ghz, switched digital will be the norm before that ever happens, besides CSO/CTB don't work real well above 870mhz so most companies are forgoing the idea of running their system that high,but having a good linear tilt is.

Signals out of the tap are designed for analog in mind, and most system's are using 256-QAM which steps itself at 5-6 dbmv below the top analog of 550mhz usally.

Power through the drop system will be gone soon with Docsis being the norm now so power passing in taps is really not needed,besides terminators,tv's and set-tops do not like the voltage.