Tuesday, October 30, 2018

KX2 operating hint

VP6D was calling CQ on 30m CW this morning with only a few takers. I couldn't resist trying to work them QRP even though I was already in the log for 30m CW.

The KX2 was right there - staring at me. What could I do?

I put it online and VP6D sounded "workable" but not much better than that. I didn't think my chances were great but decided to try anyway. Enabling the APF function did two things - it made VP6D pop out of the noise significantly and it added a third digit to the KX2's display and tuning resolution.

Then I enabled Split, found the last station worked with VFO-B, went back to RX on VFO-A and called. Then called once more and Boom - in the log.

After that, I disabled Split. APF was still enabled, but only on VFO-A with three digits (ie, down to the single digit Hz) showing. I toggled to VFO-B, where APF was not enabled, and had three digits there as well.

Long story short, if you want greater tuning resolution on your KX2, enable APF on one VFO and then go to the other VFO for non-APF operation with the 3-digits-to-the-right-of-the-decimal resolution:

This is the normal state of the KX2 in CW mode. Display only shows resolution to the 10's of Hz, ie, two digits to the right of the decimal.


Activating APF (long press of FIL button) causes display to now show single-digit Hz resolution. Active VFO is in APF mode.


Pressing the A/B switch makes VFO-B the active VFO with the same 3-digit resolution but with APF not enabled. This allows more accurate and slower tuning without the effect of APF.



  1. Hi John,

    Are you still pleased overall with your KX2? I am considering it or the KX3 for portable POTA/SOTA use, CW only, and am thinking the KX3 is overkill for my needs.

    Also, I am giving up motorcycling after 13 good years and have a Gerbing heated vest you are welcome to (includes controller, size L). Will just send to your QRZ address if you’re interested (easy for me, I am in Austin).

    Steven N5NAA

    1. Hi Steven,

      Well thanks for the offer of the vest but I may be selling my bike soon as well. We've had some great wx lately and I just haven't ridden it. I do want to make a multi-day trip soon but I think that may be the one thing making me keep the bike for now.

      I think you're right about the KX3 being overkill. I'm glad I bought the KX2 instead - I've worked lots of DX with it and never found it lacking. I even think it is superior to the KX3 in terms of internal batteries. The KX3 uses NiMH or alkaline AA cells and the KX2 uses LiIons with their much better discharge curve.

      I do like the KX2 but I wish conditions were better and that there was more CW activity. FT8 has greatly reduced the number of CW stations on the air at any given time and, although the KX2/3 can be used for FT8, it is a cumbersome process with an entanglement of cables - the Anan-10e and Flex have spoiled me in that regard with only one connection to the computer regardless of mode.

      Thanks again for your very nice offer - if I knew that motorcycling would continue to be an ongoing activity for me, I'd accept i tin a heartbeat!

      73 - John AE5X

  2. See how you feel after that long trip. I do miss the touring part of riding. Although I got to most of the places I wanted to see (Utah, Colorado, TN and NC mountains, the Ozarks), I never did ride any of the TAT although I did plenty of research about it. Good for you for taking on that adventure!

    Thanks for providing your first-hand experiences with the KX2. I have visions of doing a fly-and-drive trip out west to an area with SOTA spots. Will order a KX2 this month since there is a bit of a sale, and start getting used to it.

    73, Steven