Re: Microwave Noise


Chris Bartram G4DGU
 

An interesting question, Andy, and quite complex to answer. What do we mean by 'noise'?

Gaussian noise is the effect of random (stochastic) processes. The 'noise' generated by radio systems tends to be cyclic, albeit sometimes in a rather complex manner, but is still non-stochastic, particularly after filtering, and is thus not strictly Gaussian!

Professional transmitters - and that includes mobile phone systems - are designed to very high standards with regard to noise outputs, and usually have extensive filtering to allow co-siting of transmitters and receivers. A lot of the 'noise' from other services detected in amateur systems seems to me to be a function of reciprocal mixing, and even-order intermod taking place in our receivers. IMD2 ... is rarely considered in amateur receiver design.

73

Chris G4DGU



Andy G4JNT wrote:

Until recent years we can safely say all received noise on the uWave bands was purely Gaussian, unlike at HF where its can be moe spiky in nature.

With some of our QRN now coming from Cell Phones and other transmissions, is it still the case the noise can be considered Gaussian?  

What about VHF / UHF ?

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