SAT IF signal amplifier

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steve2222

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#15141 6-Aug-2007 20:24

Can anyone recommend a suitable signal amplifier for amplifiying the IF signal so it can be distributed around the house to feed both SKY STB and several Freeview STB's.

Would be good if it has in-built diplexer so it can take RF (VHF/UHF) feed as well.

Cheers

cyril7

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#81355 6-Aug-2007 21:13

More detail is needed, what cable is use, I presume RG6, how many meters of cable betwen the LNB and each STB, only need to be within a couple of meters, how may ways is the splitter.

Unless you have extreamly long runs (over 60meters and a two way split) amplifiers normally do more damage than good, answer the above and I can tell you what you may need.

Cyril

steve2222

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#81359 6-Aug-2007 21:24

Cheers Cyril.

About 14m for both SAT and RF from roof to STB, then split 4 ways to Freeview STB's over about 17 to 20m each run.

richms

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#81383 7-Aug-2007 00:40

You sure you need one? That should be just fine with a splitter - was for me anyway, you dont have any long cable runs, 30 meters all up and about 8dB loss of the splitter should work fine at the other end.

Richard rich.ms

cyril7

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#81396 7-Aug-2007 07:20

So thats roughly 35meters for the longest run from LNB to STB which is roughly 10dB of loss, and a 4way splitter has roughly 10-11dB of loss, 20dB of loss allup, you can have up to 40dB and not have any problems.

With 20dB of loss you dont need an amplifier, infact its most likely to cause problems, a 20dB amp will most likely overload or approach overloading closer STB. The critcal thing is to ensure that the BER or Quality figure is still ok on each STB even if the signal level is indicated a bit low.

Dont use an amp, you dont need it.

Cyril

steve2222

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#81397 7-Aug-2007 07:37

Thanks guys. Given SKY are now on horrizontal, I will set it up and see how we go.

I assume though that if I was to use diplexers to merge and demerge IF and RF signals, that I would have to allow for even further signal loss?

Steve

cyril7

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#81403 7-Aug-2007 08:20

A Dixplexer has around 2-3dB loss in the L-Band, so you will have one before your splitter, and one at each endpoint, so it will add overall 5dB loss, still you wont need a amp.

I dont know exactly what you have configured, but I would bring the Sat signal to the Sky box, and split it 2ways one to the Skybox (which will also power the LNB) and one to a diplexer. The RF from the Antenna goes to the Sky box, the RF out of the Sky box to the diplexer, then split the output of the diplexer with a 4way splitter, and on to each endpoint with a diplexer to split it up.

You will most likely need an amp for the RF path, probably best placed after the sky box, if you do use one look for a lower gain one. As previously discussed you should not need a amp for the LBand arm.

Cyril

steve2222

499 posts

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#81438 7-Aug-2007 12:40

Thanks Cyril.

That is exactly the configuartion I was thinking of.

Have you a recommendation on a low gain RF amp ie how low is low?