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APF

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Mike K5NU

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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k5oai

Re: APF

I remember seeing it said that,
using the NR was useless when you were using narrow cw filters

6) NR is rarely useful if the bandwidth is narrow. If you set your CW width to
400 Hz or less, for example, there is no point in running NR *unless* you want
to use it as a sort-of "smart squelch."
http://www.elecraft.com/K3/Lyle%20Johnson%20explains%20Noise%20Reduction.htm

GB & 73
K5OAI
Sam Morgan

On 12/7/2010 2:18 PM, k5nu wrote:

> 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
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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k5oai

Re: APF

sorry to fast on the trigger
in my pea brain I had transposed the
"apf quite uneffective with the NR on"
into 'NR was quite ineffective on cw'

my bad

GB & 73
K5OAI
Sam Morgan

On 12/7/2010 2:26 PM, Sam Morgan wrote:

> I remember seeing it said that, using the NR was useless when you were using
> narrow cw filters
>
> 6) NR is rarely useful if the bandwidth is narrow. If you set your CW width
> to 400 Hz or less, for example, there is no point in running NR *unless* you
> want to use it as a sort-of "smart squelch."
> http://www.elecraft.com/K3/Lyle%20Johnson%20explains%20Noise%20Reduction.htm
>
> GB & 73 K5OAI Sam Morgan
>
> On 12/7/2010 2:18 PM, k5nu wrote:
>> 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.
>>

Steve Ellington

Re: APF

One thing I've learned about using the APF is to keep the AF gain low. My
theory is: The ringing caused by the narrow filter is slightly weaker than
the desired tone. Reducing the audio gain tends to demphasize the unwanted
effects.
So when you first turn on APF and you think YUK, this is horrible....Try
backing down the AF gain just to the point that you hear the desired tone
and not the other junk. 73

Steve N4LQ

----- Original Message -----
From: "Sam Morgan" <[hidden email]>
To: "k5nu" <[hidden email]>; <[hidden email]>
Sent: Tuesday, December 07, 2010 3:30 PM
Subject: Re: [Elecraft] APF

> sorry to fast on the trigger
> in my pea brain I had transposed the
> "apf quite uneffective with the NR on"
> into 'NR was quite ineffective on cw'
>
> my bad
>
> GB & 73
> K5OAI
> Sam Morgan
>
> On 12/7/2010 2:26 PM, Sam Morgan wrote:
>> I remember seeing it said that, using the NR was useless when you were
>> using
>> narrow cw filters
>>
>> 6) NR is rarely useful if the bandwidth is narrow. If you set your CW
>> width
>> to 400 Hz or less, for example, there is no point in running NR *unless*
>> you
>> want to use it as a sort-of "smart squelch."
>> http://www.elecraft.com/K3/Lyle%20Johnson%20explains%20Noise%20Reduction.htm
>>
>> GB & 73 K5OAI Sam Morgan
>>
>> On 12/7/2010 2:18 PM, k5nu wrote:
>>> 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.
>>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

N2TK

Re: APF

In reply to this post by Mike K5NU

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: [hidden email]
[mailto:[hidden email]] On Behalf Of k5nu
Sent: Tuesday, December 07, 2010 3:19 PM
To: [hidden email]
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
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html

______________________________________________________________
Elecraft mailing list
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
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