Best Coax Outlet Solution for 2 TVs?

[subzero]

Hi

Apologies in advance if this question has been asked previously

What is the best solution for running two coax outlets from a single aerial (indoor loft mounted) ? Can you 'split' the aerial connection into two coax cables without significant loss of signal?

Also, I've seen double outlet sockets where one coax point is for the TV, another for FM. Do these simply run off the same coax cable and is there any degradation in quality by sharing as such? I presume this is intended to work using one device at a time, i.e either TV or Radio and hence would never be a problem anyway..

 

[Monkeh]

Splitting it will result in less than half the signal strength. The double sockets are diplexers, you'll get UHF (TV) on one port, VHF (FM/DAB) on the other, fed from a single cable.

You need a small distribution amp, and a double outlet socket (best bet is an F-type connection, make your own cables. Very easy, not expensive).

All the various bits you may need are available here: http://www.satcure.co.uk/accs/terrestrial.htm

 

[ericmark]

Hi

Apologies in advance if this question has been asked previously

What is the best solution for running two coax outlets from a single aerial (indoor loft mounted) ? Can you 'split' the aerial connection into two coax cables without significant loss of signal?

Any passive splitting device which splits the same signal will really reduce the signal. Active is far better i.e. booster or amplifier.

Also, I've seen double outlet sockets where one coax point is for the TV, another for FM. Do these simply run off the same coax cable and is there any degradation in quality by sharing as such? I presume this is intended to work using one device at a time, i.e either TV or Radio and hence would never be a problem anyway..

When combining and splitting different frequencies there are losses but also some gains. The filters also filter out a lot of noise and stop other local high-power transmitters taxi, Police, Ambulance etc. from bleeding into TV radio etc.

They are designed to run up to four different frequencies together.
Satellite
UHF TV
DAB Radio
VHF Radio
Of course to work you need four aerials at other end and a combiner which is often powered. Because the combiner is often powered much nearer to aerial than TV is often these give far better reception.

Often you have three coax cables. One has all four signals as above. A second is connected direct to a second output from LNB which supplies Sky+ or Sky HD and the third takes signal back to loft and then is boosted and fed to all bed rooms so Sky can be watch throughout the house. Often plates also have telephone connection for Sky box.

But put simple you can't get anything for nothing.

 

[plugwash]

Any passive splitting device which splits the same signal will really reduce the signal. Active is far better i.e. booster or amplifier.

A booster will boost the signal but it will also add noise and it's an extra bit of kit that must be powered, can fail etc.

IMO boosters can be a useful quick fix in some situations but the real soloution to signal level problems is a higher gain aerial.

 

[Monkeh]

Any passive splitting device which splits the same signal will really reduce the signal. Active is far better i.e. booster or amplifier.

A booster will boost the signal but it will also add noise and it's an extra bit of kit that must be powered, can fail etc.

IMO boosters can be a useful quick fix in some situations but the real soloution to signal level problems is a higher gain aerial.

True, but even with a strong signal, you need an amp to distribute to multiple points.

 

[ericmark]

Quality of pre-amp is of course a big issue. And in some cases it is nice to be able to switch it off. I had a microwave modules pre-amp on my old FT290R but my mate had a mutek front end. And both with same radio.

This did point out to me not only quality but ability to switch and although his was better quality switching off mine allowed me to select according to QRM.

OK this is amateur radio but principals are the same. Main problem with TV's is manufactures don't say how good they are. So one pre-amp will really improve matters and another will do very little even though db gain is same.

Hence why one guy says one way is best and another completely disagrees.

However the other option is an aerial for every TV and being realistic that's not really an option in most houses so only real option is how much you spend for amplifier and where it is installed.

Three main options.
1) Power in loft and amplifier.
2) Power at TV and mast head amplifier (could still be in loft)
3) Amplifier at TV
Much depends how good aerial and coax is. With good aerial and coax amp at TV will likely work fine.
But long runs and poor quality coax means in main loft or mast head best option.
With freeview only I would go for mast head but if also have sky then loft allows more flexibility.

There is no right and wrong way. It all depends on conditions unique to that installation. And with freeview either it works or it doesn't there are no half measures. And with such a variation in quality really only option is suck it and see.

The Y splitters are so cheap always worth a try. If it doesn't work then fit amplifier.

 

[ChrisFrost]

Good grief. How on earth did we get from splitting an aerial feed to microwave modules and amateur radio? Monkeh had already given a good lead on solutions. The rest of this is just beating round the bush and confusing the poor old OP!!


subzero,
Monkeh is correct when he says a Y connector halves the signal. You could get away with that on the old analogue system but digital TV is much fussier about signal level.

A powered distribution amp is what you need. We don't leave mains powered gear unattended in lofts though for safety reasons, so choose one with a separate power supply that feeds the power back up the aerial cable. If you just want the aerial feed to two rooms then a simple RF Powered Loft Box is all you need.

The big box goes in the loft near the aerial. The small box goes behind one of the TVs. Screwfix does this one - a Labgear MSA263LP/S - for around £30. Job done.

 

[Donkmeister]

Here is a suggestion I've made to various people in the past when they've asked me about the perils of weak signal after splitting their aerial to multiple outlets... It's very technical, so try and bear with me.

BUY A BETTER AERIAL.

"Signal strength" as we like to call it is all about signal to noise ratio. That's why you see a lot of reference to dBs in stuff about aerials, splitters and amps.

Let's say you stick with the current aerial. You add a passive splitter and all of a sudden you find that your TVs don't lock on because the sensitivity of their tuner is too low. Not enough signal for each TV.

So you add an amp. All of a sudden, great, your TVs work. For a lot of people that is a cheaper, easier solution as it just involves plugging in a box. Fine, if that works for you.

The more elegant solution is to buy an aerial better suited to your requirements. That way, your signal to noise ratio at the masthead is improved over the old aerial. So you now split it 2 ways, 4 ways, 16 ways, whatever, and your TV tuners receive a signal of sufficient strength.

Downsides are, you might need to spend an afternoon up a ladder or crawling round the loft, and it is sometimes a more expensive solution than buying a cheapo amp at the local shed.

Upsides are, you aren't paying to power an amp 24/7
You aren't adding a fire-risk to your loft
It's more reliable.

But hey, amplifiers are easier so no-one will berate you for fitting one...

They'll just think you're less of a man, is all

 

[Monkeh]

I'd love to see the size of the un-amplified aerial which will get me a good signal for nine different feeds here.

 

[streetlighter]

Are these powered loft amplifiers really such a fire risk ? I can understand if they are just left on the floor covered in insulation but if mounted onto say a beam with correct ventilation and connected to a fuse spur fused at 3amps.
Got me a bit worried now as i have fitted a few over the years.

 

[ChrisFrost]

The problem isn't so much the amp itself as the environment it is in. Lofts experience extremes of temperature. That stress is never good for electronics. There's also a risk of water getting in from loose tiles or leaking pipe.

Now I'd argue like you that with proper precautions then the risks can be minimised; and let's face it, nothing in this world is without risk. The issue is that lofts are forgotten spaces. It's possible to have a small leak in the roof dripping away for months before it is discovered.

What someone does and fits in their own home is their concern. But when they pay a company or individual to supply and fit then the contractor has legal obligations for the safety of the install.