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K3 Audio Peaking Filter

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John Gibson

K3 Audio Peaking Filter

Each Sunday evening, I use my K3 #820 to try to check into Kevin’s 20m Elecraft CW net. Kevin in Oregon is almost 1900 miles from me in Michigan, and I succeed only because I have a modest tri-band beam antenna at 60 ft.

Current propagation conditions make this especially challenging. Sometimes Kevin is so buried in noise that I find him only because I can recognize the rhythm of his sending.

Last evening, conditions were poor. I tuned all around the net frequency and could hear nothing of Kevin. Then I turned on my K3's Audio Peaking Filter (APF), searched again, and found him, and he was loud! When I turned off the APF, he vanished. I did check into the net.

My K3's APF made all the difference between hearing Kevin and not finding him. I am impressed that it worked so well. I thank Wayne N6KR for creating this feature for the K3.

73,

John, no8v
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Roger D Johnson

Re: K3 Audio Peaking Filter

Unfortunately, the APF is too narrow for 160m with all the lightning noise.
As I recall, we've been promised wider selectivity choice(s) but nothing ever
happened.

73, Roger

On 6/22/2020 12:27 PM, John Gibson wrote:

> Each Sunday evening, I use my K3 #820 to try to check into Kevin’s 20m Elecraft CW net. Kevin in Oregon is almost 1900 miles from me in Michigan, and I succeed only because I have a modest tri-band beam antenna at 60 ft.
>
> Current propagation conditions make this especially challenging. Sometimes Kevin is so buried in noise that I find him only because I can recognize the rhythm of his sending.
>
> Last evening, conditions were poor. I tuned all around the net frequency and could hear nothing of Kevin. Then I turned on my K3's Audio Peaking Filter (APF), searched again, and found him, and he was loud! When I turned off the APF, he vanished. I did check into the net.
>
> My K3's APF made all the difference between hearing Kevin and not finding him. I am impressed that it worked so well. I thank Wayne N6KR for creating this feature for the K3.
>
> 73,
>
> John, no8v
> ______________________________________________________________
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wayne burdick

Re: K3 Audio Peaking Filter

Administrator

We just added dual-passband APF to the K4. It's very effective at higher code speeds.

73,
Wayne
N6KR

> On Jun 22, 2020, at 10:51 AM, Roger D Johnson <[hidden email]> wrote:
>
> Unfortunately, the APF is too narrow for 160m with all the lightning noise.
> As I recall, we've been promised wider selectivity choice(s) but nothing ever
> happened.
>
> 73, Roger
>
>
> On 6/22/2020 12:27 PM, John Gibson wrote:
>> Each Sunday evening, I use my K3 #820 to try to check into Kevin’s 20m Elecraft CW net. Kevin in Oregon is almost 1900 miles from me in Michigan, and I succeed only because I have a modest tri-band beam antenna at 60 ft.
>>
>> Current propagation conditions make this especially challenging. Sometimes Kevin is so buried in noise that I find him only because I can recognize the rhythm of his sending.
>>
>> Last evening, conditions were poor. I tuned all around the net frequency and could hear nothing of Kevin. Then I turned on my K3's Audio Peaking Filter (APF), searched again, and found him, and he was loud! When I turned off the APF, he vanished. I did check into the net.
>>
>> My K3's APF made all the difference between hearing Kevin and not finding him. I am impressed that it worked so well. I thank Wayne N6KR for creating this feature for the K3.
>>
>> 73,
>>
>> John, no8v
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
>>
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John Gibson

Re: K3 Audio Peaking Filter

In reply to this post by John Gibson

Hi Bill,

Thank you for your query. My K3 has the 400 Hz CW roofing filter. Because of currently challenging conditions, I usually set my K3’s width control to 25 Hz. My preferred audio frequency is 600 Hz.

Those were my K3’s settings when I tried to check into the Elecraft CW net last evening.

I engaged the APF after nothing else worked. Following N6KR’s recommendation, I used fine tuning (1-Hz steps). I tuned around slowly near the expected net frequency of 14.050 MHz and suddenly heard net control Kevin KD5ONS calling at 14.05045 MHz.

I recognized Kevin, as I often do, by the rhythm of his sending. He was loud! When I turned off the APF, he vanished.

I believe that tuning slowly in 1-Hz steps is the secret to making the APF work.

I hope this helps.

73,

John, no8v

________________________________________
From: William Hammond <[hidden email]>
Sent: Monday, June 22, 2020 12:55 PM
To: John Gibson
Subject: Re: [Elecraft] K3 Audio Peaking Filter

Hi John, that is fantastic!! I have never experienced anything near what you describe with a K3s or my original updated K3 SN 00069. I find that a very narrow 200 hz CW filter works best for me in those conditions you so apply described. Tell me more, do you open up the filters to kHz? Please describe how you set this please. I have tried all prescriptions I have read on this reflector and had no joy with any of them..perhaps I need some schooling?

73, Bill-AK5X

> On Jun 22, 2020, at 11:27 AM, John Gibson <[hidden email]> wrote:
>
> Each Sunday evening, I use my K3 #820 to try to check into Kevin’s 20m Elecraft CW net. Kevin in Oregon is almost 1900 miles from me in Michigan, and I succeed only because I have a modest tri-band beam antenna at 60 ft.
>
> Current propagation conditions make this especially challenging. Sometimes Kevin is so buried in noise that I find him only because I can recognize the rhythm of his sending.
>
> Last evening, conditions were poor. I tuned all around the net frequency and could hear nothing of Kevin. Then I turned on my K3's Audio Peaking Filter (APF), searched again, and found him, and he was loud! When I turned off the APF, he vanished. I did check into the net.
>
> My K3's APF made all the difference between hearing Kevin and not finding him. I am impressed that it worked so well. I thank Wayne N6KR for creating this feature for the K3.
>
> 73,
>
> John, no8v
> ______________________________________________________________
> 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
> Message delivered to [hidden email]