So here’s a question I often get asked, or something a lot of people worry about when adding additional TV points. How many aerial points can I run off a single aerial?
Well the answer to this is quite simple, but let me go a little way to explain a bit more so it makes some sense. The answer is, as pretty much as many as you want! With the right equipment. (Okay so it’s not unlimited but we are talking hundreds)
Often when I say it like this sometimes I get a disbelieving look and a “But the aerial isn’t strong enough to do that”. There is an installer local to me that uses this opportunity to sell an upgraded “more powerful” aerial, but he also arrives a jobs on the back of a horse and with a big hat on so I won’t talk any more about him.
What happens when you split a signal though a conventional passive splitter?
You lose signal on each output of the splitter, the more times a signal is split the more signal that is lost. So a three way splitter will lose less than a 4 way and a 4 way will lose less than a six way and so on. Following this principle you can run out of signal. In this situation you would add an amplifier.
What happens when you amplify a signal?
The signal that leaves the amplifier will be stronger than that went in, with a few exceptions. Amplifiers rely on an electrical current to be able to do this opposed to passive splitters which don’t. Amplifiers come in varying types and some have more signal gain that others, some have multiple outputs for multiple TV points. So if you have 4 TV points you could just buy a 4 way amplifier and run all the cables from there.
It’s actually quite simple if you need to run multiple TV points, if you don’t have enough signal you install an amplifier, or a series for larger communal TV systems. If there is an aerial already in place and working fine then this 99% of the time will be fine to feed lot of TV’s. I’m aware I’m staying away from an actual number here but I can’t see many situations where 30 or more TV’s will be required in a domestic environment. The largest communal TV system I worked on had well over 100 flats. Each of those flats all had extra TV points added as well – All from a single aerial!
This doesn’t mean that you will need to install an amplifier every time you want extra TV points from a single aerial. When dealing with TV signals we are dealing with reception areas more than anything and we work as installers to keep the reception levels between in a minimum and maximum. You can install a high gain TV aerial in one location and still struggle for signal and you can install a beaten up contract aerial in another location and have way too much signal – In situations like these you would want to take the opportunity to lose some signal through a splitter rather than adding some through an amplifier.
Items for consideration
If no power supply is available for an amplifier to be installed then a mast head or line powered version can be installed, doing it this way would involve installing a power supply at one of the TV points which would send an electrical voltage, typically 12V up to the amplify on the same bit of coaxial cable that feeds the TV.
If you don’t need amplification, then it’s best to avoid it. You don’t get something for nothing. When adding amplifiers you will see an increased noise figure, amplification of signals which may not want which could cause interference and an increased risk of system breakdown and they cost more.
For this reason when installing a new system sometimes you may want to install a higher gain aerial so an amplifier can be avoided altogether, it really depends on the area. Ask your installer to run a signal test before he begins.
Cable losses – If you have a particularly long cable run than an amplifier may be required to overcome the losses as a result of the resistance in the cable. The amplifier should be added where the signal is strongest, before the cable length as opposed to the end of it!
Rule of thumb, installation goes this way. Aerial, amplifier, splitter.
If you would like to do your TV aerial installation and you're with a 20 radius of Eastbourne, please do get in touch.
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