[Elecraft] KNB2 Performance

[Darrell Bellerive]

Unfortunately, the KDSP2 is in the wrong part of the receiver chain for 
impulse noise reduction. Effective impulse noise reduction needs to be done 
at the RF/IF level before filtering. The crystal filter in the IF will 
distort and elongate the noise pulse making it much more difficult to 
eliminate.

A DSP at RF frequencies would probably be a good choice, but much more costly 
to produce. Dynamic range may also be a problem.

The cost of a good noise blanker would be a secondary consideration for those 
in high noise areas, where the $1000+ radios are seriously impaired. What is 
a $100 or more to eliminate the noise and be able to fully use the radio. 
Those with intermittant noise may be less inclined to spend big bucks.

Darrell
VA7TO


On July 18, 2005 05:03 am, W3FPR - Don Wilhelm wrote:
> Tom,
>
> I believe you are speaking of functions that can be (and should be)
> implemented in DSP (if it is to 'search', some intelligence is required).
> The KDSP2 de-noiser does provide a lot of noise reduction similar to what
> you are describing - unfortunately, it is a bit more than $30,40,50.
>
> The KNB2 deos a good job with impulse noise above the set threshold.  The
> blanking width can be modified by changing a capacitor if a different width
> is needed for a particular noise situation.  Beyond that, the addition of
> the KDSP2 adds the intellegence and levels of control to deal with other
> types of noise.
>
> 73,
> Don W3FPR


-- 
Darrell Bellerive
Amateur Radio Stations VA7TO and VE7CLA
Grand Forks, British Columbia, Canada