Odd behaviour from f input 1 and 2

[Robr_uk]

Hi,

I have Sky+ HD and have been using fine for a while. I've had occasions when one feed or the other fails, so programs don't get recorded or I get missing channels\pixelation. Things have now degraded to the extent nothing was working, so I unplugged, swapped inputs etc, to little joy. I then did one at a time, and got a picture, however it was on the input that wasn't plugged in, but the cable was touching the outer casing of the input connection! In this config (one cable plugged in, the other touching the other input connection, I get one signal.

Anyone give me an idea of whats happening? Is there a technical guide as to how the signals are transmitted, how f connectors should be fitted, what the different parts of the cable do (the wire strands, tinfoil type wrap, the white plastic core, the copper (?) core)

Many thanks

Rob

[seawright]

Hi Robr_uk and welcome to the forum.
If you can't decide which F connector is causing the problem disconnect one completely and connect the other to input one.
In the system menu (services 0 0 1 select) select single feed mode and use the green button to save settings.
Once the box has re-booted check reception signal level and quality.
If ok check again using the other lead connected to input one.

Some F connectors are screw on whereas others require a special crimping tool to attach them.
If replacing one yourself I suggest using the screw on type.
They are also available with different size barrels to accommodate different types of co-axial cable.

The signal from the LNB is carried by the centre copper core which is insulated from the earthed braid and foil by the white plastic dielectric (insulation).
co-axial cable is more than a wire, it is a transmission line which will only carry the rf signal correctly if undamaged with all connections (inner and outer) at each end correctly made.
In addition to the rf signal it also carries direct current and an audio tone from the Sky box to the LNB to provide power and select the correct operating mode for the channel multiplex being received.