Quad Lnb and multiswitch

dkane

A friend of mine has moved into an apartment which has a Communal Satellite dish and Aerial system installed. However the builders no nothing about the system and cant tell them why the system is not working.

They asked me to have a look at it today and see if I could get a signal to the points in the house.

The setup is as follows:
There is a dish pointed at 28E with a quad output LNB.
There are two terrestrial antennae with mast head amps.
There is a "multiswitch" in a waterproof box with the four cables from the dish and the feed from the antennae connected to its inputs.
There are 8 outputs from the multiswitch
There are four cables back to the four apartments in the block
There is a power adapter which takes 240 volts and outputs 24 volts to the system

No one in the block is using the system as no one knows how to use it. In fact two of them have got Sky installed even though they are not meant to put anything on the outside of the building.

When I opened the box there was a power cable into a socket in the box but this was not connected. First thing I did was to connect this up.

The lead into each of the apartments was not connected either so I found the one to his apartment and put an f-connector on it and connected it to the first output.

However there is still no signal to the plate in the house. I have tried both a TV connected directly to try the terrestrial signals and a FTA sat box to try the satellite signals.

Anyone got any suggestions at to what I have missed? do I need anything in the apartment to demux the signals?

(The multiswitch looks a bit like this one, although the connections are arranged differently http://www.hometech.com/pdf/st-201758.pdf)

Daniel

Zaphod

Most multiswitches are designed to work with quattro (4x fixed output) lnbs although some will work with quads also (4x universal).

The switch needs to be plugged in for the internal amp to work.

If you could get a receiver and tv up into the attic you could then test if the outputs from the switch are OK. If they are, then the problem lies between the switch and the outlets in the flats. If there's no signal, then the problem is with the switch or the dish.

Do the same with the terrestrial side of things.
http://www.satellites.co.uk/php-bin/forum/showthread.php?t=41947

dkane

Ok it is a quatro LNB as the different outputs are marked hi v, lo v, lo h and hi h.

Do I need any equipment inside to demux the terrestrial signal from the sat signal or can I just split the cable and run the muxed signal into both?

Obviously the power adapter needs to be powering both the multiswitch and the mast head amps?

Zaphod

The sat IF region is 900-2150MHz and the terrestrials are below 900MHz so they shouldn't interfere, but you could just temporarily remove the aerial input while checking the sat signals and vice versa for terrestrials.

Kovold

I reckon you will need a diplexer to be connected at the wall plate, something like http://www.schwaiger.de/html/D_Products/produktseiten_gb/art000059.html.

-.> Kovold

cast_iron

Surely a diplexer switch is needed in each apartment. How else could the satellite and aerial signal be inputed to their respective (seperate) inputs on a reciever?

I would try to bypass the multiswitch altogether first, by using a female/female f-coupler. Work on aerial alone first, then try satellite - as suggested by zaphod. Then when you get a picture, connect into the multiswitch.

What really needs to be done is get the people who installed it back - it is their responsibility, having been given the contract to supply it.

dkane

Does the lnb not need to be connected to the multiswitch for power?

Kovold

The LNB gets the power either from the MS or the receiver. There is no way by-passing the the MS with a quad-LNB. What you could do to confirm that the wirering is ok is to take the MS out and just put the terrest. signal on and check if you can get this at you wall plate connect to a normal TV set.

But I far as I can make out you haven't even confirmed that the actual setup is working as you haven't diplexed the single yet at the wall outlet. I would start there before going to all the trouble.

-.> Kovold