Just want to second what Don is saying here. With FSK441, wider is better. And
simpler is better. The less you do in the receiver/transmitter to limit,
filter, or process the signal, the better. Open up the receiver and
transmitter passband, turn off all the usual bells and whistles, and let the
sound card and software do the work.
I've helped a lot of guys get straightened out who were having poor results on
FSK441 meteor scatter because of:
1) Receive IF passband too narrow (open it up wide)
2) Receive equalization profile in use (turn it off)
3) Receive AGC turned on (turn it off or set it to the fastest possible
setting)
4) Transmit IF filter too narrow (open it up as much as possible)
5) Transmit equalization profile in use (turn it off)
6) Transmit speech processing/compression in use (turn it off)
You want the most wide-open, plain-vanilla settings you can get. Many of these
settings can escape your notice because they are all defaulted to values for
SSB transmit/receive and you have never changed them before. Some may be
accessible from the front panel, some will be in the menu, depending on your
radio. I don't have a K2, but will be running WSJT modes on my K3 once I get
it.
The narrower WSJT modes, JT6M and JT65A/B/C, are less critically impacted by
these settings. But to get optimal performance with FSK441, you really have to
open things up.
Bill W5WVO
Don Wilhelm wrote:
Lenny,
You have the 2.1 kHz filter width installed, and when the BFOs are
properly adjusted, the high frequency corner of the passband will be
close to 2300 Hz.
Order the SSBCAPKT from Elecraft and change the SSB filter width to
2.4 kHz, or even 2.6 kHz.
While you are at it (if you have not already done so), changing the
filter crystals on both the KSB2 board and the K2 RF board will give
you a much better filter - the crystals used in K2 below SN 2560 were
not controlled for motional inductance, and the new crystals are
much better.
73,
Don W3FPR
w2bvh wrote:
Has anyone on the list used WSJT FSK441 mode with a K2? If so I'd
like to hear about your experience.
I've tried it with a XV-50 that I recently built and so far have just
limited success. I have decoded about 2-3 transmissions (plus another
2-4 partials) over 3 Saturday morning "random hour" WSJT meteor
scatter sessions on 6 meters, but so far no successful qsos. I
operated with the K2 set for agc off, usb, and filter OPT1.
My K2 is sn 1520 and was updated to the the most recent firmware at
the same time as the XV50 build in order to accommodate the XV50 and
the KIO2 which also had to be added to the K2 for 6 meter operation.
According to the wsjt manual FSK441 uses 882, 1323 1764 and 2205 Hz
tones in its encoding. My K2's OPT1 filter has the 2205 Hz tone on
the IF filters shoulder. By eye its about 3-4 db below the passband.
(In a previous version of this email I attached a jpg of the
spectrogram plot, but evidently emails with attachments are not permitted
here. I
can send you a copy directly if it would help).
Is it possible there is too much attenuation or phase distortion of
the 2205 Hz signaling element for easy WSJT operation? I have the
OPT1 filter adjusted for the best sounding ssb voice signal
(according to my xyl's careful listening). If it's necessary to move
the filter up 150-200 Hz for WSJT, it will affect how my voice comes
across in
ssb. What are my best options for good both ssb and wsjt operation with
the K2? Are compromises required here or is there a way to get both
good SSB and good WSJT?
Thanks in advance.
73,
Lenny W2BVH
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