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Satellite Communications/Attenuation and Insertion Loss


Hi Sir,

There are few equipment that might introduce some losses when we applied along our RF chains. Common equipment are splitter, combiner and coupler. My questions are;

1. How to determine the attenuation/losses that being introduce by these equipment based on its data sheet? Is it based on insertion loss value?

2. Is there any losses if we installed coaxial surge protector?




The uplink / downlink paths each have a series of components that contribute to the gains or losses of the path.

I will ignore amplifiers, which provide gain to the path.

Everything else results in some insertion loss. So splitters, combiners, and couplers reduce (attenuate) the power in the path. Use the insertion loss parameters provided on the data sheets. The results should be sufficiently accurate for most purposes. If you need more accuracy, measure the power with and without eacn component.

Coaxial surge protectors also introduce attenuation, typically around -0.2db. describes introduction of a coaxial surge protector and notes that the performance difference was negligible.

A personal observationů About six months ago, lightning struck a palm tree about 100 meters from my home. My electrical power mains have a surge protector, but the coaxial cable for TV and Internet access was not protected. In addition to killing the palm tree, the lightening created a surge on the coax that wreaked havoc in my house. It destroyed my Internet router, my wireless router, the inputs to a printer, to a computer docking station, and to several TVs. I would gladly trade a few tenths of a decibel insertion loss for the comfort of mind that the surge protector provides.


Thomas E. Burke

Satellite Communications

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Thomas E. Burke


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Forty years of experience with satellite communications. Have held roles as system engineer on JPL Mariner 9 program and a program manager for a number of classified communication satellite programs. Served as head of TRW / Defense Communications Division / Engineering Development Operation, a 1,400-person organization responsible for all aspects of classified communication satellite design and development.

Ph.D. Chemistry, California Institute of Technology (1969) B.A. magna cum laude Chemistry, University of Minnesota (1962)

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