Aerial signal splitting question

Trevord

I am hoping to split a loft terrestrial aerial signal to feed two rooms and wonder if this plan should work.

(For the moment it applies to analogue, but TVs will be upgraded for DTT in due course).

There is just a single downlead to each room so I am using diplexers to merge/demerge the terrestrial and sat signals to feed each room.

Questions:

Do I need to connect two coax cables to the aerial or can I simple connect one coax to the aerial and then use a splitter on that so that I end up with an aerial signal to feed to the diplexer for each room.

Would splitting a single aerial signal and then running the split (and presumably weaker) signal through the diplexers ruin the aerial signal quality?

There seems to be only one coax clamp on the aerial which is why I was considering the use of a coax splitter in the first place, rather than two coax runs directly from the aerial.

Would I be better off finding some way to connect two coax cables directly to the aerial so that I avoid the need to split the aerial signal?

watty

Get a decent 4 way distribution amp with a low gain figure.
Ones with F-Connectors (screw on plugs) are usually better

Sam Russell

When you split a cable, you lose half the signal in each leg, that is half the signal goes down one leg, the other half down the other. This only happens if you use a perfect splitter. You are best to put in some form of (powered) amplifier to boost and split the signal in one go. TV cables are 'transmission lines' with a characteristc impedance (75 ohms in the case of TV cables) and just 'joining' two cables destroys this impedance and loses a lot of signal at that point. It is for that reason, joints in cables need to be done properly or signal strength will be lost.

If you have not got much signal to start with, this will be important to you.

lucernarian

A proper inductive (not resistive) coax splitter is probably the way to go if an aerial is to supply just two TVs. If reception is weak, you should have some amplification on it in the first place. A two-way splitter shouldn't have any visible/noticeable effects on reception if the existing cable's signal is good. Basically, splitting the signal properly should knock a fixed amount of the signal off the existing diplexed cable. If that already has good, snow-free analogue TV3 for example then a passive splitter will work fine for both diplexed cables if installed correctly.

If you plan to supply a few TVs from the one loft aerial, you would require an increasingly strong signal at the antenna to manage with just passive splitters and you may notice that there are frequent picture breakups where there weren't before (digital TV only) and a proper distribution amp will likely be required.

If you don't have electrical sockets in the attic you can use a masthead amp (connected to the aerial's downlead a metre or two from the aerial) and power it with a PSU that can be plugged into one of the TV cables in any room. But I don't think you can use a masthead amp power unit on a cable which is diplexed with satellite, so this may not be an option for you.

I didn't explain all of that very well so ask if there's something I didn't clarify!

Trevord

Thanks for all your replies.

Haven't looked into getting an amp yet but the analogue signal to each tv is already fairly watchable.

kooga

guys

can you split a tv aerial signal?

i have an aerial lead going into my tv downstairs can this be split in two to have the uhf signal going into a combo box and a freeview hd pvr?

Peter Rhea

Combi receivers & Freeview PVRs will have a loopthrough for the aerial signal i.e. an 'aerial-in' & 'aerial-out' socket. No need for splitters.

Only consideration will be if it remains active when the receiver is in standby.

scubadec

Ok, I havent a clue of all the technical terms so please bare with me.
I recently moved into a new (to me) house.
There is a Satellite dish on the side of the house and an aerial on the chimney (I'm presuming terrestrial).
In our Sitting room there are 2 cables which I have connected to a combi box, one does the terrestrial channels and the other does the free to air Uk ones. This works perfectly for the sitting room.
In the Attic I have Located the aerial wire from the Aerial on the roof and the satellite dish wire and from opening the inline connections I have established what each wire does.

Now, There also seems to be a box which I presume was used to divide one of the lines up and spread it around the house to the bedrooms.
Link below.... add www.
satelliteandaerialsupplies.com/product/?s=triax-370403-4-way-link-amplifier-dc-pass-f-type

Now, I disconnected all the other wires and tried to add it in at the inline connections mentioned above. When I used the terrestrial line nothing happened and the signal to the TV was lost. When I used the line from the satellite dish, the green LED light came on, but there was still no signal to the TV downstairs.

Is this box not able to function as an aerial splitter?
Im not to bothered if the Satellite doesnt work but I would like to be able to see RTE 2 for the next few weeks if possible, so I can watch the WC games.

Any help would be appreciated.