[Elecraft] APF

[N2TK, Tony]

I wonder if other setting on the K3, such as AGC, Width, NR have an impact
on how some perceive the APF? I can't believe how the signals pop out with
the APF. I have only used it on topband so far. But KH2 and 9Q could not be
heard with my pennant receive antennas. They popped out of the noise and
could be heard quite well when I turned on the APF.
I did a couple of things that seemed to help:
- Dropped my pitch tone from 600 to 500HZ. I may want to try 400HZ to see if
it helps.
- Use a bandwidth about 300-400. Found that narrower bandwidth seems to
cause some "ringing".
- Sometimes use the NR at F1-2. Don't use it with any narrower settings
cause it doesn't seem to work.
- Slight adjustment of the SHIFT seems to help, mostly going lower. 
- RF Gain is always at 3:00
- AF Gain is usually around 10:00-2:00

If I can hear the signal without the APF ON, there does not seem to be an
advantage turning on the APF. It seems only when I know there is a signal
there that I can't (telnet callout) or can hardly hear it that turning on
the APF works.

73,
N2TK, Tony


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of k5nu
Sent: Tuesday, December 07, 2010 3:19 PM
To: Elecraft at mailman.qth.net
Subject: [Elecraft] APF

Fellow Elecrafters,

Many of you have praised the current version of apf.  Since I spend 99% 
or more of my time listening for weak signals on 80m, it should be a 
very useful adjunct.  How do you utilize the apf - with NR on or off?  
My particular preference for listening keeps the NR on - never off.  I 
use 1-3 or 1-4 on cw and find the apf quite uneffective with the NR on.

That said, I have found very few occasions when the NR/NB combo needs 
anything else and am quite happy with the listening experience.  
However, if I could find a method where apf could help even more, I 
would welcome it.

I use diversity rx always, NR on always,  RF gain about 2-3 o'clock on 
both rxs, AF gain at approx. 12 o'clock.  Incidently, I very seldom use 
a filter narrower than 2.4kHz unless in a contest situation.  Just fits 
my ears/brain filter.  Antennas for rx- 4 square/beverage.

Any input would be appreciated as at present I try apf but find it of 
little use at these parameters.  Of course I am not complaining as I 
really enjoy the K3's low band abilities.

73, Mike K5NU
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