[Elecraft] K3 Audio Response - Version 3.33 Firmware

[Joe Subich, W4TV]

> Just for comparison, using the DSP demod on my old vintage 96 
> MP. It suppresses the opposite sideband perfectly. That is 13 
> years old DSP technology and firmware.

You must have an exceptional MP ... my MK V would certainly 
exhibit "opposite sideband" response in CW if I moved the 
PBT very low in frequency and then tuned to the other side 
of the carrier. I can't think of a single radio that had 
unconditional single signal response if the PBT (or filters) 
were adjusted so they provided a response on the "image." 

73, 

   ... Joe, W4TV 
 



> -----Original Message-----
> From: Arie Kleingeld PA3A [mailto:pa3a at xs4all.nl] 
> Sent: Saturday, September 19, 2009 6:31 PM
> To: lists at subich.com
> Subject: RE: [Elecraft] K3 Audio Response - Version 3.33 Firmware
> 
> 
> Joe,
> 
> With DSP demodulation the opposite sideband suppression 
> should not be a problem.
> 
> Just for comparison, using the DSP demod on my old vintage 96 
> MP. It suppresses the opposite sideband perfectly. That is 13 
> years old DSP technology and firmware.
> 
> No reason why a K3 could not match that. But it does not.
> 
> 
> 73
> Arie PA3A
> 
> -----Oorspronkelijk bericht-----
> Van: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] Namens Joe Subich, W4TV
> Verzonden: zaterdag 19 september 2009 17:06
> Aan: don at w3fpr.com
> CC: Elecraft at mailman.qth.net
> Onderwerp: Re: [Elecraft] K3 Audio Response - Version 3.33 Firmware
> 
> 
> 
> 
> > Hearing a bit of the opposite sideband is a natural effect 
> of using a 
> > very low Shift/Lo-Cut setting.  No matter how straight 
> sided the DSP 
> > filter may be, it does have a finite slope to it (if it did 
> not have 
> > slope, it would ring like crazy).
> 
> The DSP effect would be at audio.  The "opposite sideband" effect 
> is due to no longer "fixing" the corner of the roofing filter 200 
> Hz away from the carrier point.  Remember, audio frequencies are 
> imaged (folded) around the carrier.  
> 
> The DSP works the same whether audio at 200 Hz is above or below 
> the carrier.  
> 
> 73, 
> 
>    ... Joe, W4TV 
>  
>