[Elecraft] K3 fw 3.25 NR

[Lyle Johnson]

> Several posts to the list have indicated that the NR function in K3 firmware 3.25 sounds the same, regardless of which NR setting has been selected.  
> As mentioned by another list member, firmware 3.25 has an anomaly that prevents a new NR setting from immediately taking effect.
> The work-around is to change the NR setting (such as from F4-1 to F4-4), then disable NR, and then re-enable NR (the new NR setting becomes active upon NR re-enable).  I've found that NR is much improved in fw 3.25, and is now usable for me with relatively weak CW signals. 

The reason for this is that the LMS algorithm as implemented has a slow 
"decay" of computed NR filter values.  Decay is a trade off between 
response of the algorithm to signal that disappears.  A side effect is 
that if you go from less aggressive F1-x to more aggressive (F4-x) 
settings, the filter built around the signal remain in place and slowly 
decays to the more aggressive setting.

If you start with F4-x and go towards F1-x, you'll find the algorithm 
response to your changes is faster, due to the less aggressive nature of 
the algorithm at those settings.

I'm looking into ways to get it to be more responsive as you increase 
aggressiveness without compromising other parameters that must be kept 
in balance.

Thank you for your feedback on this Beta code!

73,

Lyle KK7P