[Elecraft] {k3} PSK31 tuning

[Dennis KB7ST]

Lyle and Ron,

Lyle, thanks on the PITCH freq for PSK mode.  That would explain why that
macro has the IF shifted to 1100. I've spent last two days using W1AW twice
per day data transmissions as a reference and have now developed an approach
to more quickly gain success as PSK decodes and reduce frustration. I need
to experiment a bit more but the method has significantly increased my
ability to decode weak PSK (S1-S2 levels) on 20M during West Coast
afternoons for South America.

Ron, perhaps you might want to experiment with this (unless you've given
up)?  Again, I want to increase PSK/RTTY operations while camping using QRP
levels without a computer.  I use a DSK9SQ telescoping mast and an endfed
wire with 28-gauge teflon insulation.  Wire about 130-200 feet long (I have
a splice to lengthen it depending on camp trees, etc).  Ground stake with
various length radials thrown into bushes 6-10 feet high per one of latest
QST articles on elevated radials.  Endfed goes up vertically along mast to
about 25 feet and then horizontal so height above ground not much more than
20 feet.  I'm building a compressed air launcher to get higher and try some
different antennas with the mast.  Also using the amazing T1 auto tuner.

My testing only been on 20M so far. I have 400 Hz CW and 2.8 SSB filters.

I set VFO B to CW and use PITCH of 800 Hz (highest it can go).  Starting at
14.070 and B/W of about 1000 Hz, I scan the PSK segment for strongest
signals.  I then narrow the CW B/W progressively down to narrowest 50 Hz,
SPOTing several times.  When I play with THRESHOLD settings, I notice three
modes -- high thresholds and the CWT tuning bar disappears, middle numbers
and it flickers a lot.  Low theshold numbers and the tuning aid more solid.
After getting a good CW SPOT, I check the frequency.  Let's say the last
three digits are 500.

Flip over to VFO A, now in PSK data mode and tune to the same frequency. 
Technique now varies a bit so experimenting fun.  I have progressively
narrowed PSK B/W and do several SPOTS.  The upshot is that I'm getting good
decodes with PSK B/W of around 50-100 Hz.  Based on what Lyle said about the
PSK tone being around 1000 Hz and my use of CW SPOT of 800 Hz, I suspected
the PSK freq would be several hundred Hz away from the CW freq.  The last 10
successful decodes I got, however, shows the PSK frequency to be 20-50 Hz
below the successfull CW SPOT freq on the PSK signal.  I'm not sure why that
should be the case.

In summary then, my success went way up by 1) SPOT the PSK signal on VFO B
using CW mode and PITCH of 800 Hz and narrowest B/W on CW spot then 2) go to
VFO A in PSK mode, tune the freq to the VFO B CW spot freq and SPOT the PSK
signal progressively, trying to get B/W as narrow as possible.  And, again,
I notice good PSK decode freq has been wit 20-50 Hz below the good CW SPOT
freq on VFO B.

Lyle, re RTTY,  the manual and K3 operating tips are not very clear to me as
why there are different RTTY pitch frequencies.  When I was last on HF, 2125
was the MARK freq.  What is the advantage of choosing a MARK tone other than
2125?

Here is where I'm stuck on decoding RTTY.  I tune the signal from lowest
freq and note the point at which the leftmost three bars are solid and note
the frequency.  I assume the SPACE freq would be 170 Hz higher so I tune up
half the distance (85 Hz) and don't get a decode even varying the tuning. 
When I tune higher so that the rightmost three bars are solid, still no good
decode.  I use the FSK RTTY mode that I can use the paddles with.  Maybe I
should drag the laptop downstairs (part of my disability has to do with back
pain).  It used to be that a number of non-ham band stations would transmit
RTTY for long periods of time and it was a great way to practice decoding
techniques.  When I telephoned the Seattle Coast Guard station here last
week, they laughed when I asked for the freqs and times they transmit RTTY!

Thanks for your patience, Lyle, and good luck, Ron.
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