[Elecraft] NB and NR algorhythm

[Bill W4ZV]

ANTHONY JAPHA wrote:
> 
> I'd like to add a similar suggestion, this one about the APF in the K3.  I
> accept that it works as intended, but it is not useful.  I've used APFs
> for many years and they can be very useful.  The need to severely narrow
> the bandwith to avoid ringing and the poor peak in the audio when the APF
> is peaked limit the current filter.
> 
> What I'd like to see is an APF that does not depend on a narrow bandwidth
> and that has a pronounced (tunable) peak at the desired frequency.  It
> does not need to be extremely sharp, but it could be if that is dictated
> by design considerations.  And, to keep it simple, there also does not
> need to be a choice of bandwidth through the menu,   
> 
> I'd like to hear others' ideas.
> 

I'm confused about what you wrote.  Are you in *APF* or *nor* in CONFIG:
DUAL PB?  If you don't like APF then try the normal DUAL PB function.

I'm not sure which APF you've used for many years but the K3's APF emulates
what is generally accepted to be the best APF ever implemented (FT-1000D's
original design, not the later "update"):

http://lists.contesting.com/archives//html/Topband/2000-03/msg00025.html

I very rarely use APF unless the situation demands it.  It makes no sense to
use when signals are Q5.  What is does very well is to extract weak signals
from the noise floor.  However it requires *extremely* careful tuning
(either using the 5 Hz SHIFT steps or VFO FINE 1 Hz steps).  

When H40KJ was recently on 160m, he was very weak here in the South
(propagation seemed to be favoring stations in W2 and W3).  I used APF every
time he was on and was able to copy him most days but he had no RX antenna
so he couldn't hear me in the poor propagation.  Finally he was able to hear
me with difficulty on the last day of his operation.  I believe there were
only 2 stations South of Virginia to work him and I was one of them thanks
to APF.

"Difficulty of receiving shows case of Bill W4ZV, his signal was relatively
strong  with no QSB, but to make me sure about his call sign took me seven
minutes!!!
Only thing I was sure from begening was W4, rest of the call, just two
letters was ureadable, ZM, ZF, MF could copy this in many ways. So W4ZV 
is an easy call so what you say about WB6RSE??"

http://lists.contesting.com/archives//html/Topband/2011-11/msg00020.html

73,  Bill  W4ZV


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