PX3 - Remove artifact from I/Q demodulation?

[David Patino]

Howdy All,



So on my PX3 I'm seeing the issue listed in the manual as "Dip in Spectral Response Close to VFO Frequency". Described as:

I/Q demodulation at baseband (used by the PX3 and many SDR applications) may introduce small, very narrow-band amplitude variations in the response close to the carrier. This effect varies with operating mode and usually has no effect on operation. In CW mode the artifact can be moved by switching to CW reverse mode (ALT switch on KX3). Setting RX Shift to 8.0 rather than NOR in the KX3 menu may also vary to location of the artifact.



Here's a screen cap of my PX3 with span set to just 2kHz in CW mode. The dip is 600hz above the VFO freq (CW pitch is set to 600Hz).

This exaggerates the issue but it's visible at any spans at and below 50khz.

http://i.imgur.com/p1i29Ul.jpg



Other than just moving it as the manual suggests, anyone know of any way to decrease the dip, or remove it entirely?



73, David

N9PBJ
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[John Hendricks-2]

I have the same problem and find it very distracting.  I also have found that there are additional false artifacts above and below the vfo frequency that move in sync with any change in vfo frequency.

 

John K7JLT

David Patino <[hidden email]> wrote:

>Howdy All,
>
>
>
>So on my PX3 I'm seeing the issue listed in the manual as "Dip in Spectral Response Close to VFO Frequency". Described as:
>
>I/Q demodulation at baseband (used by the PX3 and many SDR applications) may introduce small, very narrow-band amplitude variations in the response close to the carrier. This effect varies with operating mode and usually has no effect on operation. In CW mode the artifact can be moved by switching to CW reverse mode (ALT switch on KX3). Setting RX Shift to 8.0 rather than NOR in the KX3 menu may also vary to location of the artifact.
>
>
>
>Here's a screen cap of my PX3 with span set to just 2kHz in CW mode. The dip is 600hz above the VFO freq (CW pitch is set to 600Hz).
>
>This exaggerates the issue but it's visible at any spans at and below 50khz.
>
>http://i.imgur.com/p1i29Ul.jpg
>
>
>
>Other than just moving it as the manual suggests, anyone know of any way to decrease the dip, or remove it entirely?
>
>
>
>73, David
>
>N9PBJ
>______________________________________________________________
>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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Please help support this email list: http://www.qsl.net/donate.html
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