Ps: Don’t forget to change your fldigi mode setting when finished testing or adjusting.
Having a real frequency counter may be better but fldigi does a good job and the price is right. I had the TS-590 on the bench upside down with the bottom cover pulled back to expose the SO-3 pot because the touchy counter numbers change with the cover removed. You can use fldigi to check the calibration however, if you want to calibrate the frequency, you have to remove the bottom cover to reach the SO-3 calibration pot.
DSA815 FOR FREQUENCY COUNT DRIVER
I used a small jeweler’s screw driver and it worked fine. The Kenwood provided SO-3 plastic adjustment tool was way too big and was useless. It was not easy because the POT in the Kenwood SO-3 is REALLY touchy and it is hard to get the counter numbers to settle. I found it easier to tune the pot watching the fldigi counter change. The frequency of my stock TS-590SG was OFF until i added the SO-3 TXCO and I then had to adjust the SO-3 to get the tone right under the red 10 MHz marker. Be sure to push the MHz button again when finished. If you cannot hear the 10 MHz WWV tone, depress the “MHz” (just to the lower right of the 590’s VFO knob) and use the Mult-Ch to step up to 15 MHz. I tweaked the SO-3 POT until I got the counter close to 10 MHz In the screen shot shows mine at 10000000.16 and it was jumping around a little. With an absolutely perfect calibration fldigi counter would display 10000000.00. The screen shot was taken after I adjusted the SO-3 TXCO POT to get the yellow tone under the red marker or to get the counter close to 10 MHz. The WWV tone will show up as yellow line and the accuracy is displayed in the counter on the bottom menu bar. I use 1000 Hz for my fldigi "Sweet Spot" setting for CW, RTTY and PSK rather than 1500 Hz used by some for other rigs. Note the screen shot shows I use a 1000 Hz offset in the lower-middle menu bar using the adjusters on each side.
Note how fldigi displays this mode “ANALYSIS” in the lower left. I then changed the fldigi "Op Mode" to Frequency Analysis.
The reason for tuning down 1.000 was to make it easier to hear the tone. The first thing I did was to tune the TS-590SG to the 10.000.000 MHz WWV in USB mode, then tuned down 1.000 using the Mic buttons to get the display on the TS-590 and fldigi to show 9999.000. the listen to the tone method in the Kenwood TS-590 Manuals. Once checked you can then use fldigi to calibrate the TS-590 vs. The following is a URL to a screen shot showing a quick way to check the frequency calibration of your TS-590S or TS-590SG using the fldigi "Frequency Analysis" mode option.