[Elecraft] Sherwood receiver test on KX3

[Matthew Zilmer]

You're correct.  I got my mental wires crossed.  Shouldn't try to think about fun stuff like radio, while at work....

Matt Zilmer
Consultant - Product Management Dept.
Magellan Navigation / MiTAC Digital Corp.
Tel: (909) 394-6052
Cell: (909) 730-6552
Si fractum non sit, noli id reficere


-----Original Message-----
From: Matt Maguire [mailto:vk2acl at gmail.com] 
Sent: Tuesday, August 14, 2012 2:50 PM
To: Matthew Zilmer
Cc: webrehm; elecraft at mailman.qth.net
Subject: Re: [Elecraft] Sherwood receiver test on KX3

Hi Matt,

I thought that the "RX SHFT" menu item was what set the IF to 8kHz, not the dual watch (the dual watch may or may not enable an 8kHz shift as well. In a simple implementation of dual watch, the first demodulator would sit on centre frequency, and the second would shift +/- 15kHz from that. In a trickier implementation, VFO would be shifted up or down 8kHz or even more, and VFOB would then be able to range a bit further, and give a bit more than the current +/-15kHz separation).

As for whether the RX SHFT affects the centre frequency of the RX I/Q outputs, I'm not sure. It would not be hard to verify -- just tune in to WWV with RX SHFT on, and see where in the waterfall the signal appears (eg. at centre, or at centre+8kHz)  

73, Matt VK2ACL

On 15/08/2012, at 7:23 AM, Matthew Zilmer <mzilmer at magellangps.com> wrote:

> The 8 KHz IF mode is called DUAL WATCH or DUAL RX.  I/Q are "baseband" outputs.
> 
> Matt Zilmer
> Consultant - Product Management Dept.
> Magellan Navigation / MiTAC Digital Corp.
> Tel: (909) 394-6052
> Cell: (909) 730-6552
> Si fractum non sit, noli id reficere
> 
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of webrehm
> Sent: Tuesday, August 14, 2012 1:47 PM
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] Sherwood receiver test on KX3
> 
> The Sherwood test of the KX3 says this in the notes for the superscript V "At 1 kHz performance is opposite sideband rejection limited. On CW consider switching to 8-kHz IF. Note: Roofing filter disabled in this mode."
> I do not see anything in the manual about the 8 Khz IF mode.
> It is my understanding that when the roofing filter is used, which is a low pass filter, that the IF is 0 Hz.
> When the roofing filter is bypassed (FIL1) does this mean that the IF is shifted up to 8 KHz?
> What is the IF of the IQ outputs? 
> Can someone explain this to me because I am confused.
> 
> tks
> 
> Dennis
> 
> 
> 
> 
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