JnB
Rookie

Several channels missing

TWC recently upgraded our condo complex to digital.  They insalled a new Cisco adaptor, but now I cannot get several channels and several of the ones I get have a pixel probelm.  How much signal strength should TWC be providing at the tap in order to support digital TV (i.e. the box leaing to my house)?

5 REPLIES 5
Expert

Re: Several channels missing

-10 to +10 dBmv

do you have a twc modem and does it share  a 2 way splitter with the DTA?

 if suo, copy and paste the modem signal level and error log pages... Don't reset it.

 

JnB
Rookie

Re: Several channels missing

I do not have a modem attached.  The only frequency I do not get is 183 (which is NBC, CBS, CW, etc).  I do get ESPN on frequency 525 (which is a higher frequency and thus I would not think work). Below is status from the Cisco DTA for the two frequencies.

 

Tuned Frequency  183

Power Level (dBmv)  51.71

Signal-to-Noise 4294966.3 dB

Modulation Type QAM256.

 

Tuned Frequency  525

Power Level (dBmv)  -6.22

Signal-to-Noise 37.1 dB

Modulation Type QAM256.

Expert

Re: Several channels missing

Ok, that red reading is an invalid(out of range or not locked)... get a  different channel

 

I'll bet there's a filter/ trap on the line that twc needs to come out and remove

 

Highlighted
JnB
Rookie

Re: Several channels missing

Looks like the problem was that the current line had to much noise as well as not enough power from the tap to suppor the length.

 

First, the signal at the tap (TWC box that my cable from the house connects with) is only about 1.5 dBmv on frequency 183, which in this market is the NBC and CBS channels.  According to the TWC tech that came out, this is Excellent signal strength.  According to the Audio / Visual company I hired to help with the problem, this is marginal signal strength.

 

We found out that the signal strength dropped about ~2.5 dBmv after approximately 100 feet of cable from the early 1980's.  Sounds like signal strength with more modern RG-6 drops about 1 dBmv per 100 feet of cable.  Next each splitter drops the signal ~3.5 dBmv and I had 1 splitter in place.   Thus, final signal strenght on frequency 183 was about -4.5 dBmv, which is not considered desirable, but supposedly does meet minimum TWC specs.

 

Line noise was the real problem on why the DTA would not work with frequency 183, so I ended up having to pull a new line into my house.  Yes this required a cable to be burried and cutting holes in my walls.

 

Question - prior to TWC going all digital and having to use a DTA, my television would pick up the digital signals and everything worked perfect (example would be channel 7.1, 7.2, and 7.x).  I was originally told going all digital would reduce bandwidth requirements and everything would work better.  Per this incident, TWC now tells me digital systems are a lot more sensitive to line noise.  Is this true?


Not happy with the TWC attitude during this entire process.  The technician just quickly laid the problem back on me with little support saying I need a new line.  I have been without prime TV channels for almost a month as TWC's comment was not their problem the FCC mandated going to digital.  I had to hire audio visual company to help really figure this out.  Last comment is that the Audio Visual company said their business is booming due to TWC doing this to many other people as well.

Expert

Re: Several channels missing

I don't think your data is correct, something else was wrong. Cable boxes work with a -15 to +15 range. I'll bet there was a channel or band trap on the line or a crimped cable acting as one to kill the 183 mHz ch 8 qam signal

 It could have also been ingress from broadcast TV ch 8

What is your zip code?