attenuators

[dogunut]

can anyone give advice on attenuators? have noticed some of mt friends have attenuators fitted to thier v.m box's i don't
so how do you know if you require one ?
what frequancy do you require ?
what happens if you don't have/use one
many thanks for any advice

[delboy13]

attuenators are for when you have strong signal coming in they weaken it abit i think

[rocketman]

You can try one if sly1 and the disney channels are troubled with freezing

[chroma]

In a nutshell attenuation is the opposite of amplification.

They are used to reduce the signal comming from the wall by however many decibels you decide and decrease the standing wave ratio to match impedance. (idealy your aiming for a 1:1 swr but achieving this in real life is neigh on impossable for a single frequency and completely impossable over a range of different frequencies)

Its important to note that decibels are logarithmic, so if you have 12v comming in the wall and strap on a 0db filter you wind up with 12v
if it was -3db then you would wind up with 6v comming out etc.
The bigger the rating the larger the change.

[melloned]

Always wondered what they did mate , got a box of different one's and never found they made any difference ! How do you meter your signal strength as my boxes never show more than 75-80% , but don't know how reliable this is ?

[Mjolinor]

3dB is half power, 6dB is half voltage.

[melloned]

All's i was asking Mate , is based on my boxes line signal strength (75-80%) , are these accurate ? , in which case , i've just learned i don't need attenuators .
If they're not accurate and are too strong , how do i check the signal strength accurately to know what attenuator i need , or is it not that important ?.
I've 5 different Starviews scattered around the house (all split from 1 feed) and only get minor (5sec) freezng on 2 of them.

[Mjolinor]

If you have 5 boxes then there is no way you will need attenuators. Each split will reduce the signal by 3 dB so at best your signal is 3dB down on the first box and may be up to 12 dB down for the last box if the others are all in a string. Your minimum attenuation for the last box is 9 dB with 6dB for the others.