Connecting 2 TV aerials together?

[flobadob]

We live in an area of Ireland were we can pick both UK and Irish TV signals. For UK we point the aerial south and for Irish TV we point it west. At the minute I have only one aerial which is used to pick up the UK signal. My question is if I got another aerial so as to get the Irish channels how would I join the both aerials so that I can take them to the TV on one cable. Do I simply join the 3 cores together and the 3 outer bits together or do I need a sort of junction box to do it?

[beso]

The cores cannot simply be joined together. This will mess with the impedance of the system and result in huge signal degradation. They can be connected using the same kind of splitter that is used to connect multiple telvisions to one aerial. However this will also degrade the signal particularly if the aerials are in the same frequency band.

This is for two reasons. Firstly the signal from one aerial will be transmitted from the others. Secondly because the noise on the band from the non signal aerial will be combined with signal form the main aerial. Both these effects are reduced if the aerials are on different bands.

I have three aerials conneccted. High Band VHF and Low Band VHF aerials are connected via a splitter. This works because they are band specific aerials so do not tend to relaease much signal through each other. These are then fed into an amplifier where they combine with the UHF signal from antoher aerial.

Ideally you should have a switch to change the connections. Otherwise you should feed each aerial into a masthead amplifier and then combine them with splitters. In Australia where we have two VHF bands and a UHF band the amps have separate VHF and UHF inputs and this can work very well.

Where bands are the same, even with boosters you will actually be transmitting a significant amout of the signal from the other aerials. However with the amp it will be strong enough to sustain this loss.

[AlBags]

Simple ..

You look at the two channel groups of the transmitters you wish to receive at same time.
You then buy a suitable group combiner/amp and connect each of the two inputs to two antennas, each pointed in correct direction.
The outpu will then carry an amplified combination of both groups.

Some here .. (these require a separate amp, which is after the combiner, on the downlead .. powered by 12v supply in loft, usually)

http://www.tvaerials....p.aspx?categoryid=298

[beso]

In Australia the power supply is always located near the television and fed to the mashead amp through the same cable as the signal. A capacitor blocks the DC power from reaching the television and a choke prevents the AC signal entering the power supply.

[flobadob]

Thanks. I'll need to find out the correct frequencies I wish to combine though. Think it may be the top combiner but not sure.

[AlBags]

All the info you need on this site! ...

http://www.aerialsand...uttoncoldfieldtx.html