This may sound like a silly question but I am not very knowlegeable and would appreciate any response. I have a quad LNB on my dish and when out in my caravan I obviously receive freesat channels OK, I have my own Post Code logged into my Humax recorder and use two feeds from my LNB.

My question is if there was someone else on a pitch next to me and they used one of the other two feeds on my quad LNB to their receiver, if they have their own Post Code logged into their receiver will they receive all freesat channels and local weather for both post codes having two different receivers with two different Post Codes logged into the receiver connected to the same LNB, i.e. their receiver and mine. I hope this makes sense. Thanks in anticipation for any response. ATB Rob.

Their box will receive according to whatever postcode is configured in their own box, the LNB is irrelevant in this.

One thing to be aware of is that the electrical supplies need to use the same phase, for example sharing an LNB with the house next door can be dangerous. I would imagine it's okay on a caravan site but I don't know anything about caravan sites.

Many thanks for your reply. I don't understand what you mean by using the same phase supply nor why it would be dangerous if it were a house next door so I think I will play safe and just carry on using my set up for myself when I am on a caravan site. Thanks again, Rob.

The grid comes in 3 phases 120 degrees apart. Your house will use just one of them as will your caravan, your neighbour will also use one of the phases but it may be different to the one you use and if so that can be dangerous in the event of a fault occurring. I expect the caravan next to yours would be on the same phase but I know absolutely nothing about how caravan parks are wired so don't know.

As a general rule you should not share LNBs between properties (or caravans) unless you know what you are doing.

Many thanks Bob, I understand now. On a caravan site there are mains electric supply posts placed at various points and each post can have up to four sockets (16 amp each) so up to four caravans can plug into the socket to supply mains to their caravan. Each one has a seperate (I think you call it an RCD) so if you overload the RCD associated with socket that you plug into it will switch off then all you do is just flick the switch back up to put you in service again. The leads to the caravans are usually 25 meters long although caravans are normally fairly close to the supply posts so after the cable is connected the slack is usually left at the rear of the caravan on underneath. Thank you for your input.

The issue arises from the voltage difference. The single phase supply to your house has a voltage between neutral and live of 240V. Your neighbour has the same, but they will invariably have a different phase to yourself. If you were to connect a ac voltmeter from your live conductor to next doors live it would give a reading of 415V.

The reason adjacent properties are on different phases is to balance the load on the cable. Any inbalance appears as a current on the neutral conductor.

Under fault conditions this can be transferred between properties.

Basically in this circumstance all the coax leads screens are bonded together and connected to earth with a conductor capable of carrying the full potential earth fault current. .

Provided the Caravan Site is installed to full up to date safety standards you have little to worry about.

1 It would be madness to mount electrical sockets that are designed to connect to long leads on different phases within a distance that two leads could create a phase to phase voltage.

2 They will be protected by near instantaneous rcd (residual current detection) circuit breakers and also have current limiting MCB's. These devices operate in a fraction of the time a conventional fuse takes to blow and in the case of an earth fault wouldn't operate at all.

Blimey! Thank you for that but I think I met the scholars on the way back!! My knowledge extends to fitting a 3 pin plug on the end of a cable or thereabouts.

Basically right, although since 2008 the nominal mains voltage is actually 230V for single phase and 400V for three phase supplies.
It's all to do with European harmonisation, the 220V countries also changed to 230V at the same time as the 240V ones (although the allowed tolerances actually allow the voltage to rise above 240 and fall below 220 dependant on application).

A tad misleading, the EU specified a nominal voltage throughout the EU. In reality nothing changed, The 11000/415V transformers supplying the LV networks do not have onload tap changing capabilities. To change the ratios require each transformer to be taken off load and the internal winding tap moved (A massive task). Reducing the 11Kv system voltage at the primary transformer would increase system losses down to the extra current required to meet the same demand for demands that aren't voltage dependent. So nobody changed a thing, only the way the nominal voltage is expressed. If you check most peoples supply voltage it will still be around 240V in the UK, other than under maximum LV network loads - normally late afternoons after clock change means people are still at work after the lighting load is applied. . There has always been a permissible voltage variation +/- 6% except under emergency load shedding when National Grid can call for a temporary reduction of 12% (in specific areas) to avoid load reduction by disconnection. There's no magic control you can change the voltage supplied to every consumer. You can only maintain a voltage profile at the last point the supply transformers have on load tap changers with automatic control. Voltage control on the 400/275Kv network is down to the excitation levels of the supplying generators and any dynamic compensation that NGC and your ISP have connected to the network.