Cable Guy Steals Customer Amp

[gbertler]

A cable guy came to install two cable cards in my Tivo. He cheked the signal levels and said they are a bit high. So what he does is change some wiriing out and gives me this new cable amplifier. Unforunately I didn't stay in the basement where all the wiring is located the entire time he is down there. After spending 15 - 20 minutes in the basement, he comes up and asks me if the cable amplifier we had was store bought, I said it was. (Note he is caring a big bag attached to his belt the entire time he was here.)
He leaves and I check the signals on the cable boxes, not the Tivo and it states that in the 700mhz range it is: +11dmv. The 73mhz says 0dmv.
I'm not an expert, but does this seem to be an extreme range? Our basic analog channels are not clear, but I'm thinking that's because we are amping a week signal on the lower frequencies. (We have a three way splitter in our house, which is attached to a two way spitter on each port, so each port at the end is getting 15-5.5-3.5 = +6.)
The amp I did have was 15db forward and 10db reverse, he took that one and gave me one that is 15db forward and -1db reverse. My forward signal used to be 42dmv and now it's 54dmv, which seems a bit high.
I also think that there tilt compensator is too high in our neighborhood, since we have such a big difference from the low end to high end.
If anyone cares to repsond and let me know what they think about this, I'd be happy to hear from you.

 

[Chucky Cheese]

it states that in the 700mhz range it is: +11dmv. The 73mhz says 0dmv.

Most Cable Companies want the digital carrier between +10 to -10 dbmv. 1 db isn't going to hurt it.

The amp I did have was 15db forward and 10db reverse, he took that one and gave me one that is 15db forward and -1db reverse. My forward signal used to be 42dmv and now it's 54dmv, which seems a bit high.

This part is a little confussing. Most Cable amps forward is 15dbmv on the forward and -1dbmv on the return. I've never seen an house amp amplify the return. I works like this, let say at the side of the house on channel 2 you have 9db of signial on the forward and 38dbmv on the return. When you put it through a 4way splitter you loose 7db of signal through each leg, your signal now is 2db on the forward and your return is now 45dbmv. Everytime you split the line, your forward carrier goes down and the return goes up. if your forward signal was 42dbmv you would see cross modulation on your tv (One channel bleeding into the other). That's way to much signal. However if your return is 54dbmv it's good.

 

[stevenl]

Good? 54 is not good. Docsis2.0 max upstream specs are 55db. That only gives you one db of play.

 

[Chucky Cheese]

Good? 54 is not good. Docsis2.0 max upstream specs are 55db. That only gives you one db of play.

Maybe BrightHouse specs are that way. Over here it's good. Every system is different. Is 47db better?? Of course. Every house is also different. Some houses have 4 outlets some have 20. Some require 1 drop, some 2.

 

[stevenl]

Every system who runs DocSIS2.0 has the same specs. Its the Standard from Cablelabs.

Each house can be different correct, but the equipment specs are still the same. If you have 20 outlets well you will need to configure your system properly to get it below the maximum. With 20 outlets you still may only have 1 modem, maybe 2? Either way you will isolate those from the other 18 outlets so they get the best return possible. The same case for boxes apply. Most all software/hardware limits on the boxes is about 55 for the return. So you need to be creative when you have 20 outlets.

 

[Chucky Cheese]

So you need to be creative when you have 20 outlets.

:up:up