Isn't that the Enterprise?

Circling Uranus, in search of cling-ons!

cmack, you're in Houston, right?

I've had customers tell me that there's volume fluctuations on Ch 11, too.... this is with the Motorola box running through the GI HD converter, so my guess is that Warner is the problem.

create your own channel 11 with a good modulator and feed it into the cable box directly. see what happens and go from there.

You may get a great reading on the ground, only to find that you have no ground at all at Channel 11. If your measuring stuff measures with a DC signal, it will not tell you much about what is happening at that frequency.

Larry sez: "The problem occurs on only one channel. That eliminates everything except the cable box and the cable co's head end equipment."

The other thing that is not eliminated is the actual TV station itself, now that we know it is a local station.


Call channel 11's engineering department, describe the problem, and ask if they have anyone who can help figure it out. And be sure to ask if they have the number of the closest FCC field office. Maybe the TV station is running right at the hairy edge, almost out of spec, of some detail of their signal, and grounding or who knows what at your location shows their problem.


This sounds like a problem we had in the early days of color TV, when titlers first came into use -- when a white title such as a sports score came up, many TVs would emit a nasty buzz. This had something to do with the actual voltage of the sync signal. The buzz went away when the titler's sync went off.

Let's ask some questions:
In this system, when does the sync signal change? When you switch cameras or program material. When does your problem occur? When the camera changes angle ( = switching cameras) or when the program switches between program and commercials. Another hint -- the problem I describe above was worse or only occurred on live programming, where there was no recording process between the original program and the TV.

cmack sez: "The noise is worse with live broadcasts such as a football game and the client claims when the score pops up on screen the noise will be more pronounced and change slightly in tone."

The client is right, I am sure.


Also, try connecting the TV directly to the cable. Channel 11 should pop right up on channel 11. (Some systems move the channels around, so you might have to hunt for it.) See if the problem happens then.

And did you try this cable box somewhere else in the same house?

If you take the cable box output and run it through the VCR's tuner, does the problem occur the same way? The VCR will process the sync signal a little differently than the TV.

I vote for grounding as the problem because

Don't you just hate it when a program goes to commercial right in the middle of an important part?!

Perfect response, Larry!


I did not intend to send that right then, and then I shut down the computer so I did not see that it went out.

...because the problem is only happening at one location, and a ground problem will introduce 60 Hz noise into the signal, which could upset the sync somehow. I said somehow, but I have no idea how.

Try running a wire to a cold water pipe type ground, then touch it to different grounds in the system to see what results you get. I had a noise problem recently where connecting to the cable itself made the noise disappear, while touching the ground of any other component increased the noise.