Line Amplifier does not increase the quality

designbai

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HI,

I have installed DishTv in my building. I am living in Dubai. It is a 3 storey building and the dish antenna is connected centrally.

Tenents in the 3rd floor receive good signal & strength. I am in 2nd floor.

One of the vertical frequency is very weak, which is 12727/V/27500.
I bought a 10db line amplifier and connected near the receiver. After I placed the line amplifier, I loss some percentage of quality what I was receiving earlier.

Can any one help me, how to improve the quality & strength.

Thanks and any help would be much apprecaited.
 

BombedOne

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Go buy bigger dish.
 

rolfw

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No point in inserting a line amplifier at the receiver end, as you have nothing much left to amplify, you need to either install a larger dish, or put the line amplifier/amplifiers nearer to the dish so that you are amplifying good low noise signal.
 

Robbo

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Yes, putting an amplifier where the SNR is already insufficient, will not improve it, it will always make it worse. This is because of the noise figure of the amplifier itself.

The noise figure logarithmatically expresses the ratio of the input and ouput signal to noise ratios of a device, which for amplifiers is always worse on the output as more noise is always added.
 

designbai

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Thanks a lot for your replies. Dish has LNB with 4 output which directly goes to Mixer. Then mixer distribute it to each flats.

Do I have to place the amplifier near the Dish Antenna or the mixer.

I already have 120CM dish.

Thanks,
 

Robbo

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I think you are going to have to put it after the "mixer" because if you put it before, you will effect everybody elses system too, and without knowing the system design, you could end up overloading the "mixer".

After is safest as it will only effect your feed. If the SNR there is insufficient, then there is something badly wrong with your distribution system.
 

BombedOne

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120cm is not "big" by any means.

"big" starts at 180cm at least...
 

rolfw

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I would normally install a four way IF amplifier before the multiswitch (I presume that's what you have).
 

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In order to find the best point to connect the line amplifier you have to measure the signal's level at the start and the end of the cable.

If the signal of the LNB is strong then the amplifier connected next to LNB will saturate the amplifier.
 

Channel Hopper

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designbai said:
One of the vertical frequency is very weak, which is 12727/V/27500.
I bought a 10db line amplifier and connected near the receiver. After I placed the line amplifier, I loss some percentage of quality what I was receiving earlier.

Can any one help me, how to improve the quality & strength.

Take it out of the system.
 
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