[Elecraft] K2: Problems With PSK

[Don Wilhelm]

  Jon,

How do you have the RTTY FL1 BFOs set?  It sounds like you are 
attempting to use the default settings for the RTTY filter set, and that 
will not work well.

Enter CAL FIL (with the internal probe placed in TP2), and first set 
RTTY FL1 to the OP1 filter.
Then go to SSB and observe the BFO settings (tap BAND-) for both LSB and 
USB (write them down).
Then go back to RTTY mode and set the BFO for RTTY rev to the same value 
as the USB BFO, and set the RTTY non-rev BFO to the same value as the 
LSB BFO.

That should produce a good signal and a good waterfall display.
The FL1 BFOs are used for transmit in all cases, and RTTY will transmit 
through the filter on the KSB2.
FL2 thru FL4 can be set to anything you want because they will only be 
used during receive.  I normally set FL2 to 1.00, FL3 to 0.70 and FL4 to 
0.40, then center those filters at 1000 Hz.  Attempting to center them 
higher will cause you to run out of BFO range in RTTY normal.  The 
narrow filters are good for RTTY operation (most others will likely use 
the full width OP1 filter) - set the Mark frequency in MMTTY (or other 
RTTY app) to 915 Hz and it will allow you to narrow the filters down so 
you can avoid QRM (tune with the VFO instead of clicking on the waterfall).

If you have questions about using Spectrogram to set your filters, take 
a look at part 3 of the K2 Dial Calibration article on my website 
www.w3fpr.com.

73,
Don W3FPR

On 10/10/2010 8:13 PM, Jon Perelstein wrote:
> I'm having problems with PSK (and other digital modes) on my K2.  CW and SSB
> seem okay.
>
> Rig
> ------
> K2/100, KSB2, power set to 20 watts.   RTTY (Reverse) for PSK.
> MFJ-941E Versatuner to a Carolina Windom about 35 ft in the air.
> SignaLink USB into an Acer Aspire One running Win XP (SP3)
>
> On 80/75 meters, I can get a 1.2:1 SWR.  CW and SSB look good (good forward
> power reading on the MFJ).  However, with PSK, the best I can get is 5 watts
> forward showing on the MFJ, but it needs 5 bars of ALC on the K2.  With 1 bar of
> ALC I get about 3 watts out according to MFJ.
>
> On 40 meters, I can get a 1.0:1 SWR.  CW and SSB look good, and I can get about
> 8 watts out on PSK with 5 bars of ALC, and about 5 watts with 1 bar.
>
> 30 meters is about the same, but with a few more watts, on 20 meters it's still
> a few more, etc.
>
> CW and SSB are good on all the bands.
>
> I also tried PSK using SSB (USB) rather than RTTY (Reverse) and got the same
> results.
>
> Anybody have any suggestions about where I should start looking to see what the
> problem is?
>
> Thanks.
>
> Jon
> KB1QBZ
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