Coax Splitter with Charter QAM?

[gerberdude]

So I used to have a OTA antenna feeding my HDHR a HD signal, but the signal would occasionally skip or stutter due to bad reception, so I decided to split my Charter cable and feed it to the HDHR to get my HD that way.

I take the existing two way splitter that connects to the cable from the wall, and replace it with a 4-way 5-2300mhz splitter. (I now know that I should have used a 5-1000mhz splitter since I am not using satellite maybe this is part of my problem?)

One jack goes to my analog PVR-150, one to my cable modem, and the other two to the HDHR.

Last night was the maiden voyage for the new setup.

We're watching Lost live in the living room, (not via Sage, just plain live TV), when the TV says "Weak or scrambled signal" and the show just stops, about 15 minutes in, only to resume a few minutes later.

I know that my Sage server is recording Lost, Biggest loser, and maybe something analog also, all simultaneously.

I later check the Sage system messages and find out that Biggest Loser, and Lost both had recording problems, and Biggest Loser even failed to record altogether.

Nothing like this has ever happened, so I am pretty sure it's because of these new splits.

So questions:

Is this because I have split the signal too much, and would splitting it in the office where the server is cause it to drop out in my living room even though the TV is on a totally different wall jack?

Should I add a amplified splitter of some kind? If so, where?

Should I redo the way that the splitters are set up?

[david1234]

as I understand it, a 4-way splitter is like putting in a "tree" of 2-way splitters. Your going to see some pretty good signal loss from it.

The easiest way to be sure that's the problem, would be to bypass the splitters and plug the cable right into the different tuners. If everything works doing that, then most likely an amp will fix the problem. ... I missed the part about the TV not being watched with Sage- that means there's also at least one splitter, probably in your cable box adding to the signal loss.

Since the TV wasn't hooked up to Sage, the signal from the cable company was probably flaky to start with, and the extra splitters didn't help.

[gerberdude]

I'm starting to think that this might just have been a fluke. The cable in the living room shouldn't have cut out just because I added more splits in another part of the house, should it?

Am I missing something here?

[blade]

Originally Posted by gerberdude

Is this because I have split the signal too much, and would splitting it in the office where the server is cause it to drop out in my living room even though the TV is on a totally different wall jack?

Depends on how you have it wired. From the way you described the setup it doesn't sound like it should.

Should I add a amplified splitter of some kind? If so, where?

Once again it depends.

Should I redo the way that the splitters are set up?

Probably, but once again it depends on how everything is wired.

There are a lot of sites that explain how to determine signal loss. You might want to take a look at this one. I just found it on Google and skimmed it so I can't vouch for everything on it, but based on my understanding of how all this stuff works the diagrams looked reasonably accurate and should provide some insight.

My setup is:

Cable From Pole --->2 way splitter--->Cable Modem
                           |
                           |
              TV<----- 4 way 15db amp--->PVR-500
                          |        |
                          |        |
                 2 way splitter  2 way splitter  
                       |   |            |   |
                       |   |            |   | 
                     HDHomeRun1     HDHomeRun2

Ideally you want the amp as close to the source as possible (within reason) and no splits before the amp. If you have a cable modem then you either need to split the signal for the modem before the amp or have an amp with a return path. I have a split before my amp because the one I'm using is quite a few years old and I'm not certain it has a return path.

The signal for each tuner is about as even as I can get it using the parts I already have. The PVR-500 has 1 input and splits the signal internally. The only TV in the house that is connected to coax has a run of 25 feet from the amp compared to less than 2 feet for my other tuners. So that helps bring the signal for those two a little closer to that of the HDHomeRun's that have an additional 2 way splitter between them and the amp.

I'm sure there are others here that know far more than I do about this stuff, but maybe this will help get you started.

[gerberdude]

I guess I'm kind of at a loss, since I live in an Apartment complex. I really have no idea where the cable comes from, or how it is split before it comes to the drops in the walls. The apartment complex pays for the expanded basic charter package, so conceivably I could be sharing my signal with every other person in my building.

I doubt that is happening, but at this point I just don't know.

I am thinking of picking up one of these:

http://www.radioshack.com/product/in...ductId=2103092

I wish I could wait and just see if this problem repeats itself, but at that point I am potentially losing out on shows that I want to watch.

[Fuzzy]

About the only way a splitter on a different jack would affect that jack in the living room, would be if the splitter itself was poor/faulty. It could be bleeding ths signal down (in essence, sort of shorting it out), which could drop the strength everywhere.

[gerberdude]

Originally Posted by Fuzzy

About the only way a splitter on a different jack would affect that jack in the living room, would be if the splitter itself was poor/faulty. It could be bleeding ths signal down (in essence, sort of shorting it out), which could drop the strength everywhere.

Here is the splitter that I installed:

http://www.consumer.philips.com/c/ca..._27/prd/en/ca/

I guess it's a pretty good one, I don't really know. Although, I now know that a 1000mhz unit would be just fine. I have another 1000mhz Philips splitter that I will put in when I get home.

I don't suppose that could have anything to do with it?

[david1234]

Here's a pretty good explanation of how the splitters affect the signal

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

[gerberdude]

Originally Posted by david1234

Here's a pretty good explanation of how the splitters affect the signal

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

That's a good explanation of how the signal can degrade. I think when I get home I'm going to plug my computer directly in to my cable modem to try and find out the signal strength after the 4-way split. It's not the same as using a $1500 cable signal tester, but I don't really have $1500 lying around right now.

Can anyone recommend how strong a signal needs to be for the HDHR to actually use without dropping out?

[Taddeusz]

Depending on your cable modem you may be able to use it to determine your signal strength. My Motorola cable modem has a private IP address of 192.168.100.1. It will tell me the incoming power level. Keep in mind that a usable cable signal is anywhere between -10 and +10 dbmv. If it falls below -10dbmv you will start to have problems.

If you know how strong your signal level is with absolutely no splits or have a cable amplifier with a set output level you can determine your final signal level by subtracting the values for all your splitters. 2-way give a -3.5dbmv drop, 3-way and 4-way give a -7dbmv drop.

[zoundz]

As always, YMMV, but I have my Charter cable split a bunch of ways. I have an amplifier in line and then the 4 outputs of the amp are run to the Charter STB, 3 Hauppauge cards, the tv, and both inputs of my HDHR. All of this works just fine for me. The clear QAM's are pretty much rock solid on the HDHR. Assuming that you're not on a <buy food or pay for cable> budget, the easiest way to find out what will help is to get an amp and put it in line. You definitely want to use the widest bandwidth splitters you can, since the specs on the label may be a bit optimistic compared to the reality. 1000MHz is cutting it a bit thin. The other thing is to make sure that all the cables in your splitter network are up to par and that the F connectors are nice and snug. Just a little bit of looseness and everything will go to hell.

[Taddeusz]

Originally Posted by zoundz

1000MHz is cutting it a bit thin.

1000Mhz splitters are just fine. Analog CATV and QAM don't go above that. Even my cable modem doesn't operate above 1Ghz. It's currently at 117Mhz incoming and 21.1Mhz outgoing.

[Fuzzy]

This highest cable frequencies are about 800Mhz, so a 1GHz splitter is plenty. You won't gain anything using a higher one, except a HF noise getting through.

Being in an apartment is never ideal, cable wise. Mainly, because in most cases, the lines are owned/controlled by the landlord, not the cable co. If they are using shoddy amps, or don't have them adjusted properly, it'll be hard to get it working well (you may find great signals at the low end of the spectrum, but poor signals at the high end). Ideally, they should ahve the amps configured such that all signals, at every jack, are at about +5dB. They should have the skew adjusted such that that +5dB is consistant across the band. This +5dB is ideal as it provides enough room for some moderate splitting (up to 8 ways) without bringing the levels too low.

Either way, if you are ever needing an amp in-house, there's problem upstream, and should be fixed there (either by the cableco, or the landlord).

[gerberdude]

Originally Posted by zoundz

You definitely want to use the widest bandwidth splitters you can, since the specs on the label may be a bit optimistic compared to the reality. 1000MHz is cutting it a bit thin. The other thing is to make sure that all the cables in your splitter network are up to par and that the F connectors are nice and snug. Just a little bit of looseness and everything will go to hell.

So you think that I should just stick with the 5-2300mhz splitter? I guess that's not what is causing me problems.

I wonder if there is a short in one of the cables. They are all RG6Q with compression connectors. I made them myself, but maybe there is a problem with the cables. I will maybe swap those out too when I get back.

[wrems]

Maybe you should back up and test your connection with minimal splits? This will help you identify if the problem exists in your apartment or leading up to your apartment. Try plugging in only the HDHR via a straight feed from the wall no splitters, purest possible signal. Record a show and see if you have problems. Then go from there.

[gerberdude]

Originally Posted by Fuzzy

Either way, if you are ever needing an amp in-house, there's problem upstream, and should be fixed there (either by the cableco, or the landlord).

I'm starting to think that maybe my problem isn't the signal being too weak. I'm wondering if one of my coax cables is bad, or maybe to splitter is bad.

I guess the unfortunate thing is that other things could be going on in the building that might be messing with my signal, compounding the problem.

[gerberdude]

Originally Posted by wrems

Maybe you should back up and test your connection with minimal splits? This will help you identify if the problem exists in your apartment or leading up to your apartment. Try plugging in only the HDHR via a straight feed from the wall no splitters, purest possible signal. Record a show and see if you have problems. Then go from there.

Yeah, I think I'm going to have to try and replicate the issue. Maybe I'll just load it up with HD stuff to grab tonight and see what happens.

I hate intermittent problems. So hard to diagnose.

[tomfisk]

For what it's worth, I installed one of these on my server setup. You need to make sure that the amplifier isn't blocking the return path, especially if you have STB's. You'll also want to terminate any unused outputs with 75 ohm terminators (2nd Amazon link).

http://www.amazon.com/gp/product/B00...ef=oss_product

http://www.amazon.com/gp/product/B00...ef=oss_product

[voidpt]

One other tip. I had sort of the same problem on my tuners connected over coax (in Norway, same basics though). One thing that I verified had serious impact was my coax cables. In the end I bough some good quality RG-6T, 3x shielding & 1mm copper core cable. And then cut and made connections at exactly the optimal length. Used those F-connectors all the way (makes the copper core go from point to point). This 1mm center beat nearly all the other varied cables I had. I cut some of them open afterwards and some really had tiny copper cores. Usually a good store will give you several choice of coax cables, bought in varied length, and give specification on lost dB per length (thicker center, usually less).

[Taddeusz]

Originally Posted by tomfisk

For what it's worth, I installed one of these on my server setup. You need to make sure that the amplifier isn't blocking the return path, especially if you have STB's. You'll also want to terminate any unused outputs with 75 ohm terminators (2nd Amazon link).

http://www.amazon.com/gp/product/B00...ef=oss_product

http://www.amazon.com/gp/product/B00...ef=oss_product

I have the 4-port version from that company. Noisier that the one that the cable company supplied, which is also 4-port. Probably because it outputs at a slightly higher power level than the one from them. They both provide a return path, however the devices need to up their power levels to get through. I was having problems with my cable modem wired through the amp so I have the cable modem attached via a tap connected before the amp.