satellite radio amp / coax power FREE cabling and networking Helpdesk
 Question by Eric Huang posted 28 Jun 2007
 satellite radio amp / coax power
I installed a Sirius satellite radio antenna on my roof and connected it through my structured wiring enclosure with RG6 coax. Initially, my signal was poor, but I installed a Pixel Technologies XM/Sirius Radio SBA In-line Amplifier (SBA-1) and my reception was much better. Since the amp doesn't have any power injection, is it really just a noise filter?

Second, I was told that a coax power inserter is only necessary if my run is over 250 ft long. My run is only 40 ft long, but I am still having occasional signal loss. Would my set-up benefit from adding a DC coax power inserter? I'm afraid that I may be adding additional noise to the line without any benefits to reception.

 Answer by Dmitri Abaimov posted 06 Jul 2007
Dear Eric,

Without power the amplifier is actually an attenuator so you might as well just remove it and see what happens to the signal. Also Sirius transmitter works in 2.32GH band whereby RG6U cable is usually only rated until 1.5GHz beyond which bandwidth (almost) no manufacturer even measures the performance. So, you are bound to have extra losses in the cable no matter what length. In addition, each connector/splitter has its own bandwidth limitations and most (high end) are rated 1GHz or slightly above that.

So, if removing a powered off amplifier does not help, I would go for the power injector. I am assuming the model you have do actually receive the power via an injector. You will undoubtedly aplify noise as well as useful signal but the digital transmission may do wonders sorting this out, as long as there is a signal to sort through in the first place.

Dmitri Abaimov, RCDD

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