APF question

[VE3WDM]

When using the APF function on my K3 I am getting a real tinny sound to the point were it is difficult to understand the code. I was wondering if settings were ok.
Here is what I do.
1. Zero beat the CW signal with the spot feature and tuning is set to fine.
2. The filter is set at either 400hz or 350hz
3. The APF setting is a .60 I also adjust this setting to see if the audio improves but it does not seem to.
4. I do try to fine adjust the VFO (fine setting) for the signal to jump out. All that happens is it gets more tinny.
Any suggestions?
Mike
VE3WDM
     
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[Bill W4ZV]

VE3WDM wrote

When using the APF function on my K3 I am getting a real tinny sound to the point were it is difficult to understand the code. I was wondering if settings were ok.
Here is what I do.
1. Zero beat the CW signal with the spot feature and tuning is set to fine.
2. The filter is set at either 400hz or 350hz
3. The APF setting is a .60 I also adjust this setting to see if the audio improves but it does not seem to.
4. I do try to fine adjust the VFO (fine setting) for the signal to jump out. All that happens is it gets more tinny.
Any suggestions?

APF is not intended for signals much stronger than the noise floor.  On stronger signals it sounds tinny because its 30 Hz filter is on the verge of ringing.  If you can hear a CW signal Q5, you don't need or want APF.  It's intended for the 339 and 449 signals buried in noise.  It can bring these signals to Q5 but must be peaked carefully because the BW is so narrow.

73,  Bill

Hello Mike,

The APF, because of the high "Q" will naturally produce ringing with a
strong signal. Just back down the RF Gain control until you can clearly
hear the keying elements. However, I'd suggest that if the signal is
that strong to begin with, you probably don't need to use the APF
function. It is particularly effective though on very weak signals that
are near the noise floor.

73, Dale
WA8SRA

On 11/11/2011 1:16 PM, Mike Weir wrote:

> When using the APF function on my K3 I am getting a real tinny sound to the point were it is difficult to understand the code. I was wondering if settings were ok.
> Here is what I do.
> 1. Zero beat the CW signal with the spot feature and tuning is set to fine.
> 2. The filter is set at either 400hz or 350hz
> 3. The APF setting is a .60 I also adjust this setting to see if the audio improves but it does not seem to.
> 4. I do try to fine adjust the VFO (fine setting) for the signal to jump out. All that happens is it gets more tinny.
> Any suggestions?
> Mike
> VE3WDM
>    
> ______________________________________________________________
> 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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