Any Cable Experts Here?

"Brickman" (legomaniacman) 03/03/2016 at 19:37 • Filed to: None

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I’ve been having problems with our cable signals. Higher channels are fine, but the lower channels up to 20 or so skip and have code 225. All the TVs are like that.

I have Comcrap, but that’s all there is. We want to get Xfinity cable internet soon, but with the cable not working 100% im worried the internet wont work or keep dropping.

I went into the attic to investigate. I haven’t done any of this mess. Previous owners 25+ years ago and my dad put two new cables a few years ago to replace whats bad. Not sure if he replaced a splitter, but these look quite old.

IDK why he put my cable (white one) on the input side of the splitter. Im going back up tomorrow to fix that even though my cable works, except lower channels like the others.

Sorry for the lousy cell phone pic.

I drew a picture of what the current set up is like.

Here is my idea. I want to put a powered splitter and updated cables. Put a 1002mhz for the internet router and to the TV.

Would this work or would I just need one big high quality splitter?

shop-teacher > Brickman 03/03/2016 at 19:46

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I would try one big high quality splitter first, and see if that works.

1111111111111111111111 > Brickman 03/03/2016 at 20:04

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Get splitters from platt or a place where you can get really low loss, also use better coax for less loss.

Also if you get Comcast business internet they will rewire to the demarc and the support is better. I’m getting 25/15 with no caps and 5 statics for 120$.

-this space for rent- > Brickman 03/03/2016 at 20:17

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Step 1, bypass all the splitters and make sure the source isn’t garbage.

Step 2, buy new things as required

Step 3, profit

Busslayer > Brickman 03/03/2016 at 20:18

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I had trouble with my cable when I had it installed a couple years ago. List signals, poor picture quality. They sent a tech out. He looked at all the wiring and immediately said the problem was the original installer ran one cable above a florescent shop light I had in my basement. I didn’t really believe him, but he rerouted the cable and never had any more problems.

Could you have something causing interference?

What about bypassing all those splitters and temporarily hook a TV up more directly to see if you can isolate the problem before throwing parts at it.

N51fanatic > Brickman 03/03/2016 at 20:41

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RF engineer here, I can’t see the exact types of splitters you have but to give yourself a rough idea, the splitters are sending equal power to each output. Meaning, 2 way sends 50% to each output, 3 way, 33% to each output, 4 way, 25%. Add to this, you are now splitting it again after the first split. So in your master bedroom your getting 50% of 33% of the original signal. Add in line losses from cable attenuation, and that could be why your having problems. Loose connections, and other interference in the terminations could also be issues, as could EMI from other sources.

Brickman > Busslayer 03/03/2016 at 20:46

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Supprisingly the cable runs along this 2x4 with the telephone line, nothing would be causing interference.

Could hook up one TV, I need to find the main line though lol.

Brickman > N51fanatic 03/03/2016 at 21:02

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Thanks. One is a Radio Shack UHF VHF FM Hybrid splitter. Other is a GE 4-way digital 5-2500mhz Power pass all ports. Can’t think of anything that would cause any interference other than the splitters themselves and a couple of the cables are definitely not the newer type. No loose connections.

I do have a new 1002mhz 2-way splitter that I’ll test out. I’ll find the main cable and put two TVs on that and see.

I do know the cable in the pedestal outside is old. Someones house as a thicker orange cable.

N51fanatic > Brickman 03/03/2016 at 21:09

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Hybrid splitter just puts different bands on same cable (i.e. UHF, VHF). There are other components called directional couplers. Meaning they have the ability to send uneven amounts of power to different outputs. For example, let’s say you have a tv right next to the 1st splitter, and one one the other side of your house upstairs. The one on the other side is twice the distance away. A simple 2 way splitter would be inefficient as you are sending the same amount of power to both. You are wasting the power needed to go twice the distance to the other tv on the one right next to the splitter. For the sake of this example, you would need a coupler that could send 10% to the tv right next to the coupler and the 90% to the other side of the house to overcome the cable losses and any additional splitter losses.

RF design 205 lol

Clown Shoe Pilot > Brickman 03/03/2016 at 21:18

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Good advice from N51fanatic. I HATE troubleshooting this sort of thing at work, mostly because it’s always a damn emergency. Give a bunch of people 2 days to complete their setup and testing before an event and nobody will turn any of their TVs on until the morning of the event and discover that their internal cabling is a complete shitshow. Luckily, I have a very very nice test tool. It usually goes something like this:

Rando: None of my TVs are working, there’s something wrong with your system

Me: Hmmm... let’s take a look. I’m going to unplug your equipment and plug the cable from my system into this test set... Ok, I see all the channels, with good power levels. What channel are you having a problem with?

Rando: Hmmmm... must be my equipment. Do you have splitters and amplifiers I can borrow?

Brickman > N51fanatic 03/03/2016 at 21:21

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I think I understand what you are talking about :D

e36Jeff now drives a ZHP > Brickman 03/03/2016 at 23:33

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So, I actually work for the great Satan. A powered amp will fix your issues provided that the signal coming in the house is clean in the first place. Some powered amps have a line with less loss in it, thats the one you want to run to your internet.

However, if you haven’t had a tech out to look at it, I’d do that. If he thinks it warranted(and to me it sounds like it probably is), he will replace the splitters and/or install a powered amp for free.

If the house is 25 years old and has never had its underground or aerial drop replaced they might need to be replaced. Usually they are once every 10-15 year type things. Again, that’s something that would be replaced for free if its broken. It’s also possible(but less likely) the tap has issues. There is really no way to tell exactly what the issue is without reading the signals in the house itself.