tv aerial coax run

[bananaspark]

I'm setting up a centralised media cupboard away from the living room in my flat, (digibox, tuner, vcr dvd etc all go in here along with infra red remote extender) and I;ve run the coax from the socket in the living room into there also.

but regarding the vhf signal, can I 'T' off from the coax onto a new tv socket en route before it runs into the media cupboard, also can I connect the dvd into the same aerial line to save on doubling up the cable run?
I will be running a 5 metre scart cable out of the the cupboard to the tv in case the above doesnt work.

 

[electronicsuk]

but regarding the vhf signal, can I 'T' off from the coax onto a new tv socket en route before it runs into the media cupboard, also can I connect the dvd into the same aerial line to save on doubling up the cable run?
I will be running a 5 metre scart cable out of the the cupboard to the tv in case the above doesnt work.

I assume you mean UHF, which is the band that TVs operate in. You can 'T' off the coax to another outlet, but only with a proper coaxial splitter. Don't be tempted to simply splice the cables as if they were carrying power, it might work but will give a terrible signal due to improper shielding and impedance matching.

If your DVD player has a UHF output then you can combine it with your terrestrial signals down the same cable, again using a proper splitter/combiner. You'll have to find a free channel to tune the UHF output on the DVD player to, but otherwise it should work fine. If you want to combine a number of devices then you really need to look at using a proper tuned channel filter/combiner, otherwise stray signals at the outputs of the various devices you're trying to combine will degrade overall performance.

If your DVD only has a SCART output then you will need a UHF modulator, personally I'd save yourself the effort and run it over SCART, you'll get a better picture anyway.

 

[bananaspark]

thanks, whats the best way to connect the cable to the new socket and then out again? get a t adapter? or carefully strip relevant parts of the wire and 'loop' them into the socket connectors...the second if done well should be better than 1st.

 

[electronicsuk]

thanks, whats the best way to connect the cable to the new socket and then out again? get a t adapter? or carefully strip relevant parts of the wire and 'loop' them into the socket connectors...the second if done well should be better than 1st.

No, under no circumstances will the second route be better than the first. What you have to remember is that RF signals are not like power at all, there's a lot more going on than meets the eye.

TV coax cables and distribution systems have a characteristic impedance of 75 Ohms, and proper T splitters offer correct impedance matching to ensure this remains the case. Splicing the cable in any manner whatsoever (even trying to create a loop in-out) offers no impedance matching whatsoever, it might work but results will be unpredictable at best, especially when you have something plugged into more than one outlet.

Don't be tempted to do it. Far too many electricians think that treating TV signals in the same way as power is acceptable, but it isn't. Get a proper T splitter and put it either below the floor or in the ceiling above and run one cable down to the socket. This is common practice on large MATV distribution systems in flats and the like, where a large 'trunk' cable carries high power signals which are then split to individual outlets along the trunk using a 'tap'.

Of course, if your wiring wasn't already in place then a better option would have been a multi-outlet distribution amp and a cable to each outlet.