[Elecraft] FT8 DXpedition Mode test.

Stephen Shearer sm.shearer.01 at gmail.com
Thu Mar 8 11:48:14 EST 2018


Don, OK I had to test this again and look at the manual.  I "thought" I 
tried shift but brain cells are getting old...

I used fldigi to see a nice 0-4K audio spectrum.
I went to 40m (shouldn't matter), set DATA A, set BW=4.0, Adjusted FC 
from low to high 1.28 to 1.64 with *1.5.
     FC ... If I change it over its full range the lowest it goes is 
375HZ (and that may be 10dB down?).
     If I change BW=3.0, same but High end varies.
     With BW=4.0, only high end varies.
     If I make BW=1.7, I can move low end up but not below the ~400HZ...

I have latest firmware, MCU 02.90 DSP 01.52

If I use USB...  BW=4.0 FC=*1.5  I have an audio range from 200Hz to 
3500Hz ??
I even went back and zeroed my RX EQ.
I guess I can't use DATA A with FT8 in DXpedition Mode.
It won't matter with other modes as only DXpedition mode needs RX at 
300Hz...
And I may have been the only one using a KX3 for the test?
*I think the answer is that the problem is not **with me, its firmware 
limits...*

The WSJT-X software does other "tricks" to move the TX freq keeping it 
within the TX bandpass, 1500Hz +/- 500Hz (it looked like...)  Note, not 
relative to "issue", just info.


BTW, thanks for all you do for the Elecraft community!

73, Steve WB3LGC


On 3/7/2018 1:42 PM, Don Wilhelm wrote:
> Stephen,
>
> In DATA A, use the SHIFT (PBT II) to shift the passband down.
> The widest passband is 3000 Hz. which is consistent with your 400 to 
> 3500 Hz observation.  I suggest shifting it to 150 to 3150 Hz. It will 
> work fine for most soundcard data modes.
>
> The K3/K3S has the same behavior, but it is not a problem.
>
> 73,
> Don W3FPR
>
> On 3/7/2018 11:47 AM, Stephen Shearer wrote:
>>
>> 8.   My KX3 with "Data A" has a wide bandpass of 400Hz to 3500Hz and
>>     shifting the RX down was not going to work with the software shift
>>     for the report, I "guess"...
>> 9.   I changed my KX3 to USB, removed CMP and RX/TX audio EQ. The
>>     lower RX cut-off would receive the FOX on the assigned freq.
>> 10.   I looked at the KX3 manual C5 for a way to set the passband low
>>     end cutoff while in Data A mode.  Nothing found.  Does the K3s have
>>     the same problem?
>



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