[Elecraft] Fwd: no8v: APF Primer? - 2020-08-25

[kevinr]

Here is John's method for using the APF feature on his K3.

    73,  Kevin.  KD5ONS




-------- Forwarded Message --------
Subject: 	no8v: [Elecraft] APF Primer? - 2020-08-25
Date: 	Tue, 25 Aug 2020 12:20:14 +0000
From: 	John Gibson <gibson at alma.edu>
To: 	kevinr <kevinr at coho.net>



Hi Kevin,

I have used APF to find you on ECN/20. When QRN/QRM was high and signals 
were weak, APF sometimes enabled me to hear and recognize you by the 
rhythm of your sending. Without APF, I could not hear you at all.

Normally I tune for you with a WIDTH of about 25 Hz, but when I switch 
to APF, I also broaden WIDTH to its default CW value of 400 Hz to help 
minimize ringing. I also change the tuning rate to FINE to avoid missing 
the APF peak. It should be possible to automate both of those changes on 
the K3, although I have not yet done so.

APF is no panacea. It does ring, which makes copy difficult. But 
sometimes it saves the day.

73,

John, no8v

________________________________________
From: elecraft-bounces at mailman.qth.net 
<elecraft-bounces at mailman.qth.net> on behalf of kevinr <kevinr at coho.net>
Sent: Monday, August 24, 2020 10:33 PM
To: Elecraft Reflector
Subject: [Elecraft] APF Primer?

I have used APF a number of times. Sometimes it worked, but often the
ringing makes it hard to hear anything intelligible.

I have a two families of questions to hopefully remedy my problem.

1) What are the best band conditions to try APF? Does it work under
medium QSB against medium to high noise levels? Is it better on 80, 40,
or 20 meters?

2) What are the procedures to use APF on your K3, KX2, KX3, etc.? How
should I set the bandwidth of the filter I'm already using? How do I
peak the APF performance? Does the set up change on a per band basis or
does one setting fit all cases?

As I mentioned, I have gotten it to work well a few times, but usually
the signal sounds buried in a hard walled well. Then I get emails
telling me how well it worked during ECN. My interest is renewed, hence
my questions.

Help?

Kevin. KD5ONS

-

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