Science channel SD 122

navpack

For months now, the Science Channel in SD (channel 122) is distorted, freezes, breaks up.

Happens somewhat randomly, but during the programming, but the commerical content. Tried several times to put a tech support ticket into Verizon, but the only response I have gotten is to do a STB reset. All other channels are fine. And watching the HD on iPad is fine.

Anyone else seeing this?

Thanks.

phil

PaulKolodner

This is a common problem. I am posting the text below in multiple places because I believe I have a solution:

I’m a physicist with long experience in electronics and optics, and I have solved this problem on two set-top boxes in my house. I removed the coax cable between the wall jack and the set-top box and replaced it with one that was 3” shorter. End of problem. What?? Why should something so silly actually do anything? Well, here’s what I think is going on: The RF radiation that enters that cable can be weakly reflected from its ends. If the wavelength of the particular channel has the correct relationship to the cable length, a resonance can be set up, just like blowing into a flute creates distinct tones. This resonance can cause problems. Changing the length of the cable by a quarter of a wavelength shifts it out of resonance. The channels I had problems with use frequencies 727 MHz and 636 MHz. (You can find this using Menu/Settings/System Information/Info in FiOS). The formula for the wavelength in this kind of coax cable is: wavelength in inches = 7793 / frequency in MHz. This gave 7793/727 = 10.7 inches and 7793/636 =12.3 inches. A quarter of those lengths is 3 to 4 inches. I had a cable lying around that was about the right length – being off by an inch or two wouldn’t matter. I got lucky the first time. If this had not worked, I would have tried some other lengths within a wavelength of the original cable length.