Electric Shock From Coax Cable

electro-shocks

Hi,

First of all for some reason every 4/5 days i lose at least 3/4 of sky channels with the no signal message. The only way it seems to come back is to recut the coax cable and refit the f connectors. This problem only happens in the second room.

Tonight it went again and i checked the cables and anytime I touch the coax and any connection point on the sky box I get a steady electric shock.
Should this be happening?

Im sick of lossing channels every 4 days or so, I'm going to have to get on the phone to sky. Theres no way I'm paying a call out charge tho, since day one I've been having this problem.

Apogee

Your eponymous experience with the coax is perfectly normal - the satellite receiver is sending a small current to power the LNBF attached to the dish, as well as sending a 13V or 18V signal to switch between Vertical/Horizontal polarities.

However, having to recut the cable makes no sense (unless you have kids/pets messing with the coax?). Most likely it's a fault with one of the output ports on the LNBF (if you can access the dish, switch around the cables) or else the tuner in the receiver is on the way out.

Tell Sky that you'll cancel your subscription and see if they will sort it out.

Liameter

electro-shocks wrote: »

anytime I touch the coax and any connection point on the sky box I get a steady electric shock.

This is a common experience. It occurs because the Digibox chassis is "floating" (not earthed) and it has suppressor capacitors that shunt a tiny amount of current (at about 120 volts) to the chassis. It's possible to earth the chassis.

The copper cable inside the 'F' plug attached to your LNB can oxidise slightly and cause a disconnection. As a precaution, you should always coat the wires with silicone grease before fitting the 'F' plug and make sure there's a film of grease on the inner copper wire when you push it into the LNB connector. The grease keeps out air and moisture, thus preventing oxidation.

See http://www.satcure.com/tech/silicone.htm
and http://www.satcure.co.uk/tech/fconn.htm

However, this may not be your problem. Your Digibox or LNB could be faulty. If one of your receivers is a Thomson Sky Digibox, it could be the culprit. It's quite common for PSU failure in a Thomson box to cause "no signal" with another Digibox.

Peter Rhea

Liameter wrote: »

It's possible to earth the chassis.

Not a good idea according to http://www.double-insulated.com/

These products must NOT have a safety connection to Earth

Liameter

I agree. I had in mind a resistive discharge method but I wasn't going to elucidate because most people won't understand how to do it safely.