[Elecraft] Final K3 APF Lab Test Results

[Wayne Burdick]

We just did a *very* accurate sweep of the APF passband from the original (4.17) and new (4.22) beta releases. Lyle has the data in spreadsheet form and will send it out on request. It's too big to attach to a reflector posting. 

Bottom line: There is no difference between the two. This is not surprising, since we did not change the filter algorithm. 

Any difference must be attributed to noise and signal conditions, filter bandwidth settings, or APF tuning vs. actual signal pitch. This is the nature of APF; it is most effective under specific conditions. Try turning it on, and if it doesn't help, leave it off. 

73,
Wayne
N6KR


----
http://www.elecraft.com

On Nov 20, 2010, at 12:16 PM, John Seney <john.seney at gmail.com> wrote:

> Hi All:
> 
> I have the same experience as Igor. There is an APF sweet spot that either moved or
> disappeared. 
> 
> Would it be helpful if there was a GUI that let us save, load, share, and see all of 
> the various K3 parameter settings that we are adjusting?
> 
> On Nov 17, 2010, at 11:53 PM, Igor Kosvin wrote:
> 
>> Sure, you are right, but you would not deny that using same set of
>> parameters (NR/NB, WIDTH, PITCH, RF, etc) the APF circa 4.17 and 4.22 should
>> give very similar results since the code of APF remains the same. After
>> playing few days with 4.22 I find myself having to turn off APF to better
>> receive weak CW stations. I don't have explanation for this. With APF on I
>> find it difficult to distinguish dits and dahs of weak signals. With 4.17 it
>> was much better for me. That should be apples-to apples comparison, I think.
>> I don't claim to be expert though, listening is very subjective IMHO.
>> 
>> Regards,
>> 
>> Igor, N1YX
> 
> 
> 73, 
> 
> John Seney
> ARS WD1V (fn42gw)
> 603 785-2413
> 
> 
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