[Elecraft] RE:KNB2

[Don Wilhelm]

David,

Yes, the KNB2 does have a threshold level - anything below that level 
will not trigger it.  There are two threshold levels available from the 
front panel (Hi and Lo).  You could dig into the KNB2 circuit and lower 
the threshold if you really find it advantageous, but turning on the 
preamp may help (and will indirectly provide 4 levels of NB threshold).

Make your judgment about which is best according to your noise source. 
Remember that the KNB2 works best with impulse noise (like gasoline 
engine ignition), and will not do much for a constant 'popcorn' noise or 
atmospherics - the DSP noise reduction is best for those kind of noises.

73,
Don W3FPR

David N. wrote:
> Well after following Dons directions about Q21 I found
> 
> That the noise blanker worked so I tried the test
> again
> Well still no effect for giggles I turned on the
> preamp and the noise blanker worked after shutting off
> the preamp the noiseblanker continued to work.
> So I guess a certain amount of signal is required to
> trigger it. I normally do not run the preamp. 
> And by the way the preamp does work as advertised 
> So my next questions is what else do I need to do to
> correct having to turn on the preamp to get the KNB2
> to kick in?
> Thanks
> David KR4OW