Originally posted by: danplaysbass
Ok. I'm running comcast digital cable and broadband internet. Main cable comes in and goes into a 3-way splitter. One to main LR, one to office, one to BR.
Office connection is for internet (no TV) and has no problems.
LR is split 2-way, one to Digital box/tivo and the other to TV tuner. Cable box/Tivo have no signal problems, however, when tuned to either tv reception is weak with bad signal quality. I plan on adding a slingbox to the LR setup so then I will have a 3-way split there.
I called comcast about it and they want to send and tech out but I think it would be cheaper to fix this on my own.
So I'm thinking I could put some in-line amps into the system. Where should I put them and which ones are good.
I don't have a kick-ass setup here so I'm going for cheapest solution here. What do you guys think?
A 3-way splitter has 2 ports that drop 3.5 - 4dB per port and a third that drops 7-8dB. They should be marked. The higher the number the higher the loss and more loss = bad. If you have the LR on the high loss port and plan to add another splitter indoors you can see that the loss can add up quickly, not to mention the attenuation (roll off) of the signal level through the cable. The higher the frequency the faster the roll off. The Comcast system is probably built to run from 11MHz to 750MHz or higher. The loss at 750 is roughly 6dB per 100 Ft of coax. You could easily lose 16dB between the point of contact with the house and the last device in the line. Also, when looking at the spliters be sure to see that they are marked with 5-1000MHz (5Mhz - 1gig). If for example they top out at 500MHz all frequencies and services above that will drop like a rock.
If you want to add your own amp make sure it is good to 1gig and is bi-directional. It must allow the signal to pass in both directions. If it does not you will lose your modem or any other device that interacts with the outside world... EOD and VoIP for example.
Look for one
like this and place it at the first splitter. You need to amplify the signal here before the signal drops too far. Many people add amps right behind the set or after the last splitter and wonder why it didn't help. Amplifying after the levels have dropped only amplifies noise and you don't want that. Don't get a huge amp. A 15dB amp should be enough for what you need. Too much and you risk driving the modem or other device beyond the design specs.
You will also need a power inserter (looks like a splitter with a clearly marked port for the DC power connection) but that should come with the amp. Don't use a cheap amp, cable or conectors. Trust me.... you will regret it in the end. They leak RF like a sprinkler. And if it leaks out it can "leak in" as well. Off air frequencies like radio, TV, HAM, etc will enter the coax and screw with your toys.
This isn't rocket science but it may be easier in the end to let them do it. At least they will own the work and service it if it fails.
Before you decide, check the 3 way splitter outside and see what port is feeding the line you want to tweak. If it's on the 7dB port move it to the 3.5 port. This may add just enough to get you what you need for the line you are having trouble with. If all sets in the house have bad reception then I would have my doubts about an amp being the solution.
This may or may not help but it's somethign to think about!
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