[Elecraft] K3 and noise

[David Woolley]

Ron Kenwood wrote:
> I have a continuous S7 to S8 noise level at normal SSB bandwidths. If
> I had to describe the noise, I would say it sounds like amplified
> background band noise. The source is outside my house. Removing the

If the noise is close to gaussian, there is nothing any receiver noise 
reduction system can do with it, to actually remove it, although it can 
do things like muting the receiver in gaps in the speech, if the speech 
is above the noise, or generating a graphic equaliser that de-emphasises 
frequency not also being used for the speech.

> 
> I have read glowing reports on the effectiveness of the noise blanker, 
> here and elsewhere. I am wondering if the type of noise is part of the 

Noise blankers require that the noise be isolated spikes that can be cut 
out without removing too much of the signal.

> equation, and I just have a type of noise where the noise blanker is 
> less effective, or am I doing something wrong, or do I just have 
> unreasonable expectations?

Knowing the source of the noise might help, as it might give a clue as 
to its structure and therefore whether there is anything that can be 
done to mitigate it.
> 
> My next step will be one of the noise canceling gadgets, if I can't 
> improve the K3's noise performance.

For gaussian noise, the best option is to eliminate it at source. 
Failing that, put it in a null in the antenna pattern will help, 
providing the noise has a well defined direction.  I assume you are 
referring to the sort of noise cancelling device that works by 
distorting the antenna pattern.

Note that such devices are not suitable when the antenna is already very 
directional, or the sky noise is not significantly greater than the 
receiver noise (the device is likely to contribute its own receiver noise).

-- 
David Woolley
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