Electric Shock From satellite Cable!!!

[DanPaula]

Hi. Just bought a satellite system for caravan which workd great. However, when I disconnect sat-finder I'm getting a mild electric when unscrewing the metal connections to fit direct to LNB. I tried even by setting up then turning power off but there must be still current left in the cable.

I've checked connections and the inner and outer coax is not touching anywhere. Does anyone else have this problem? Is this normal? It's quite annoying.

Many Thanks, Dan.

 

[Rod_5041370]

If you are using a 230vac digital receiver, try reversing the mains plug, especially if it is the "figure of eight" input type.

 

[DanPaula]

Cheers Rod but it's not a figure 8 type. There's no way I could reverse it as it's like a "jack plug??" type with an inner and outer connector.

 

[Rod_5041370]

This jack plug seems like a 12vdc connection in which case you shouldn't be able to get a shock unless the mains adaptor is faulty or the AC is coming via the SCART socket on the TV.

If the TV is a 230vac one, try reversing the line and neutral, but first check the incoming mains polarity to the caravan.

 

[DanPaula]

would you suggest trying on a different tv here at home? I haven't taken it to the van yet but when I do it will be on 12v.

 

[DanPaula]

Rod, just tried on a different tv and it's fine. Must be the old tv thats dodgy. Many thanks for the advice, dan.

 

[JeremyClarksson]

This is from memory so the voltage figure may be wrong.

The coax cable carries an 18V supply which is used for the LNB and possibly a motor drive (we have one at home).

I am not absolutely sure it is necessary but you can usually disable it in the menu to see if this removes your signal.

I have never bothered because this voltage is harmless, even if it is a little unsettling.

 

[Lutz]

The LNB on the satellite dish receives needs a signal to enable it to differentiate between horizontally polarised and vertically polarised transmissions. Horizontal polarisation is achieved using an 18 volt supply and vertical polarisation a 13 volt one. In addition, the LNB gets a 22kHz signal to identify the highband. The 22kHz signal can also be used to switch between two (or more) LNB's, or internally, in the case of twin or quad LNB's, connected to the same receiver, or to steer a motor driven satellite dish.

 

[MikeAce]

As stated above, its perfectly normal, i used to fit satellite systems, in the rain on an aluminium ladder i used to get quite a sting in the tips of my fingers when cutting back the cable to fit the f connector.

Dont let it worry you, i get it when i put my tripod and dish up too, as lutz stated there is voltage in there but nothing sinister.