[Elecraft] K3: Passband Offsets per Mode

[JAMES ROGERS]

Rich, you win the prize..... Exactly and that is a scenario that in my  
transition from the FT2000 to the K3 that I was having trouble with.  
If I have tuned to a signal on 7.1MHz, that signal will be in the  
center of the selected filter.  DM-780 was telling me it was 1.5 +/-  
kHz away.

When I would shift the IF to receive say a lower frequency signal in  
the waterfall of DM-780 then I would be out of the pass band of the  
filter and PANIC!, no power out.

I just knew there was an explanation sitting right there before me,  
but for some reason just could not quite get there. Actually, Gary at  
Elecraft called right before I read your e-mail and after he and I  
walked through somethings, we got on the same page and it is all  
resolved.

Fantastic support as always from Elecraft and its users.

73s and thanks to all who responded, Jim, W4ATK (Could we chalk this  
up to my being 77 today?)


On Sep 21, 2010, at 12:22 PM, Richard Ferch wrote:

> Jim,
>
> You need to separate what your software is doing from what the radio  
> is
> doing.
>
> If you turn the radio on without using any radio control software, and
> if after changing modes you press and hold the SHIFT button, the radio
> will change to its default (NOR) filter settings in that mode. The
> defaults are (or at least, this is what they are on my radio):
> SSB: 0.15 kHz to 2.85 kHz
> CW: PITCH - 0.2 kHz to PITCH + 0.2 kHz
> DATA A: 1.3 kHz to 1.7 kHz
> AFSK A and FSK D: PITCH - 0.2 kHz to PITCH + 0.2 kHz
> Note that the PITCH settings in CW and in RTTY (AFSK A/FSK D) are  
> separate.
>
> Evidently the default bandwidth in CW and DATA modes is 0.4 kHz, and  
> in
> SSB it is 2.7 kHz. The default centre frequency is the selected  
> PITCH in
> CW and RTTY modes, and 1.5 kHz in SSB and DATA A.
>
> If you change any of the shift/width or lo/hi cut settings, the radio
> will remember the changed settings on a per-mode basis. The remembered
> settings persist through power on-off cycles; turning the power off  
> and
> on does not restore the defaults. If you change the bandpass  
> settings in
> one mode, that change will have no effect on other modes. All four  
> DATA
> sub-modes change width and offset from the default centre frequency
> together, although the default centre frequency changes between
> sub-modes. (Actually there are two remembered settings per mode,
> labelled I and II - see the Owner's Manual for details.)
>
> If you set everything back to the defaults, turn your control software
> on and change modes from the software, and you discover that the
> resulting bandpass settings are different from the defaults, that  
> tells
> you that the software must have sent commands to the radio to select
> bandpass settings different from the radio's defaults. In that case,  
> you
> would have to ask the software developers why they chose the  
> particular
> settings they did.
>
> 73,
> Rich VE3KI
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