[Elecraft] Best way to use NB and NR?

[Don Wilhelm]

The K3 noise blanker, and in fact any noise blanker works by producing 
"holes" in the receive path.  That is what blanking means - if an 
impulse is detected, it shuts off the receive path for a specified 
period of time.

That will not "take away" from the reception of faint signals, but if 
combined with gaps in the received signals because of impulse events 
occurring at the receiving station, it may make the copy of faint 
signals difficult because of the blanks in the received data stream.

In my opinion, it should only be used when necessary, not all the time.  
If you have constant static pulses or automotive ignition noise or 
distant lightning surge problems at your QTH, then it may be beneficial 
to run the NB at all times, but if you do not need it, keep it off.  
Remember that the NB responds to impulse noise - it will not be 
effective in reducing slow rise time noise like atmospheric noise or 
power-line induced noise.  NB needs a fast rise time to be effective.

NR is a different animal altogether.  It will reduce or eliminate things 
like atmospheric noise or power line noise - it works on correlation 
principles.  That means is it is normally quiet while it looks for what 
might be a valid signal.  When it finds something that appears to be a 
valid signal, it builds a filter around it and sends that result to the 
K3 audio.  What it looks for is highly dependent on the parameters set 
for the K3 NR algorithm as well as your local noise.  There are several 
settings provided for in the menu.  Do a little experimenting with your 
chosen mode and local noise situation until you discover what works best 
for you.  The settings for CW will likely not be good for SSB.  Try the 
settings to find which works for your particular situation.  This is not 
a case of "one size fits all", customize it to your particular noise 
source.   With NR on, the desired signal should be enhanced, but really 
weak signals may be at or near the noise level, and may not appear as a 
valid signal, giving the appearance that weak signals may be covered up 
and not detected.  I suggest (after experimenting) that you normally run 
with NR turned off, but turn it on if the situation warrants it.

73,
Don W3FPR

On 9/29/2011 12:15 PM, tomb18 wrote:
> Hi,
> I was wondering if anyone could give me some hints as to the best way to use
> the NB and the NR?
> Most of the time I use the nr and there seems to be little effect of the nb
> (maybe one-two s units?)  Does the nb take away from faint signals?  If not
> should I always just use it?
>