Hi,
I found this forum in a web search to learn how to improve my home cable service. That search led me to a specific thread found on this site dated ~2003. It was very informative and I imagine still current, but prompted the following questions.
Our house was wired several years ago during renovation to have capacity for cable service for computer and several TVs. After entering the house at the basement, the cable service meets a splitter: Regal, GRS2DGH, 5-1000MHz, 110dB EMI Isolation. One line marked with a tag “DATA Do Not Filter or Alter Configuration” goes directly to our computer. The other one proceeds to an upper floor closet in order to drop back down and serve the main TV. Two additional rooms were pre-wired from their outlets back to that upper floor closet location, but they were never hooked up to the feed from the basement. At that upper floor closet, I want to split the feed from the basement to accept the main TV and two additional pre-wired locations.
It seems like the signal will have dropped below zero, to -1.5dB, by the time it gets to the two additional rooms with all the splitting I’m doing (based on what I understand to be the drop in signal strength each time). I understand that dipping below zero is not good, although I don’t know technically why. I also read about someone else using a “Directional Coupler” in stead of a splitter as the service enters the basement. It preserved a majority of the signal for the TVs on one leg, and allocated only a small amount for the computer on the other leg. If I were to do that, it seems I would have enough signal left to serve all three TVs successfully (above zero signal and without an amplifier). I also read to avoid amplifiers, too.
Does this sound like the right approach? Any other suggestions?
Would the line that today serves the computer, still be able to serve a TV in the future? What’s the difference between what the computer needs/gets and what the TV needs/gets from the cable serving it? What is the tag “Do Not Filter of Alter Configuration” referring to?
Previous posts that I read warned against store bought splitters/couplers. What about more specifically offering a list of recognized quality manufacturers? Or even better, a list of those to avoid. Please explain the concerns.
How does one measure the signal? With specialty equipment? Is it that important? Or do I just assume that the cable company is bringing ~9db to the house?
And finally, for in-the-room cable to serve the TVs in the two additional rooms, I need to purchase new cable. Anything to avoid or to be sure to look for there?
Many thanks to anyone who has read this to the end, and even more thanks for any advice in reply.
Regards,
wgbjr
Splitter/Coupler at Service Entry
OKwgbjr wrote:Hi,
I found this forum in a web search to learn how to improve my home cable service. That search led me to a specific thread found on this site dated ~2003. It was very informative and I imagine still current, but prompted the following questions.
Our house was wired several years ago during renovation to have capacity for cable service for computer and several TVs. After entering the house at the basement, the cable service meets a splitter: Regal, GRS2DGH, 5-1000MHz, 110dB EMI Isolation. One line marked with a tag “DATA Do Not Filter or Alter Configuration” goes directly to our computer. The other one proceeds to an upper floor closet in order to drop back down and serve the main TV. Two additional rooms were pre-wired from their outlets back to that upper floor closet location, but they were never hooked up to the feed from the basement. At that upper floor closet, I want to split the feed from the basement to accept the main TV and two additional pre-wired locations.
You should be working for a cable company.It seems like the signal will have dropped below zero, to -1.5dB, by the time it gets to the two additional rooms with all the splitting I’m doing (based on what I understand to be the drop in signal strength each time). I understand that dipping below zero is not good, although I don’t know technically why. I also read about someone else using a “Directional Coupler” in stead of a splitter as the service enters the basement. It preserved a majority of the signal for the TVs on one leg, and allocated only a small amount for the computer on the other leg. If I were to do that, it seems I would have enough signal left to serve all three TVs successfully (above zero signal and without an amplifier). I also read to avoid amplifiers, too.
Does this sound like the right approach? Any other suggestions?
Your calculated worst case value of -1.5 dbmv will work fine. A "not good" signal threshold would be -7 dbmv and a "run out and buy an amp" threshold would be -10 dbmv. Drop amplifiers should be avoided if possible. If you can find a directional coupler with a 6db tap for the computer then use it instead of a splitter but be aware that the signal gained by using a DC will be minimal (approx. 1.5 db).
YesWould the line that today serves the computer, still be able to serve a TV in the future?
The tag is refering to a high-pass or window filter that some cablecos insert into branches that will not be sending upstream data. Your modem sends data upstream so adding a filter to that leg of the splitter would disable the modem. Noise is a big problem on the upstream and filters do help a little bit.What’s the difference between what the computer needs/gets and what the TV needs/gets from the cable serving it? What is the tag “Do Not Filter of Alter Configuration” referring to?
Avoid the high and low end accessories. By that I mean you don't need a splitter that can be used for DBS and you definitely don't need one of those gold painted things that they sell at the local dollar store. Home Depot and Lowes have a good selection of 2, 3, and 4-ways that are flat to 1 Ghz.Previous posts that I read warned against store bought splitters/couplers. What about more specifically offering a list of recognized quality manufacturers? Or even better, a list of those to avoid. Please explain the concerns.
With special equipment.How does one measure the signal? With specialty equipment? Is it that important? Or do I just assume that the cable company is bringing ~9db to the house?
Your modem and/or set-top-box can give a good approximation of the analog signal strength and noise level.
The stuff they sell at the home improvement store will work fine but you'll have to install you own connectors. Use crimp connectors with the proper tool on RG-6 cable.And finally, for in-the-room cable to serve the TVs in the two additional rooms, I need to purchase new cable. Anything to avoid or to be sure to look for there?