Posted by
jperelst on
Oct 02, 2010; 3:20am
URL: http://elecraft.85.s1.nabble.com/K2-Heat-On-Digital-Modes-tp5572168p5593538.html
I'm having a problem with the BFO settings for RTTY. The outputs on the
different filters are centered at significantly different places in the
waterfall. For R-Reverse, they're as follows:
Filter Width Center on Waterfall
------- -------- ---------------------------
FL1 2.5 KHz 1.1 KHz
FL2 1.3 KHz 2.0 KHz
FL3 0.6 KHz 1.6 KHz
FL4 0.3 KHz 1.1 KHz
Thus, a station centered at 1.0 KHz on my waterfall when using FL1 is not
visible in the waterfall when using FL2 or FL3, but is again visible when using
FL4.
My understanding from the main K2 manual is that R-Normal is LSB, and R-Reverse
is USB. Based on that, I used the KSB2 LSB BFO settings for R-Normal and the
KSB2 USB BFO settings for R-Reverse. The settings for R-Reverse were:
Filter Width BFO
------- -------- ---------
FL1 Op1 4916.3
FL2 1.40 4916.1
FL3 0.70 4915.5
FL4 0.20 4914.7
These R-Reverse BFO settings are the same as I have set with USB.
By comparison, for USB, using the same BFO settings, I get all four filters
centered at about 1.1 KHz. A station at 1.0 KHz on my waterfall is visible on
FL1, FL2, FL3, and FL4.
I took the measurements with a straight stereo cable from the headphone out to
the line in on my computer. I also re-did them with a SignaLink USB and got the
same results. Similarly, I tried both fldigi and DM-780 as my software and got
the same results.
What am I doing wrong? I didn't find anything in either the K2 Operating Guide
or the KSB2 Operating Guide for any BFO calibrations related to the RTTY mode.
By the way, I re-did the KPA-100 bias adjustment on my rig and it was pretty
close to correct to begin with. I did notice that the K2 Operating Guide
recommends against transmitting at more than 10w for more than 1-2 minutes at a
time for continuous duty cycle RTTY/data modes.
As always, thanks for your help,
Jon
KB1QBZ
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