My K1 worked so well, I built a K2! It took me thirty hours over three days. Everything works, but I am now battling a lack of sensitivity, especially on 20m. I do have full output power on all bands however. The kit wasn't harder than the K1, it just took longer. Right now it is the basic version, but I plan on adding the auto tuner, SSB card, audio filter board and internal battery kit.
Control board and front panel, end of day 1:
RF board, end of day 2, receiver subsection.
My happy Elecraft family:
Hopefully the sensitivity problem will be easy to fix, I just have to find the problem. I did have a bad solder joint on TR7 (the one missing on the RF board photo). Maybe the problem is related to it. I just don't have the time right now to troubleshoot. I will have to, because I want everything to work perfectly. As it is, my K1 receives much better than the K2, not cool.
I might yet build a KX1... That however, with the 40m SSB kit I am expecting from ozqrp.com will be, for quite some time, the end of my radio building career. Then I'll start really using them! The more I am listening to HF and CW, the less I am interested in VHF...
I am not going to do a full review, there are plenty of sites that do, including eham.net. Here are my impressions however:
As far a building goes, it was the same fun level as the K1. Everything fits, the manual is exemplary, the only thing missing was the rotary encoder nut and washer. I did use one from a discarded Gonset Communicator potentiometer, so that K2 has some historical parts!
The K2, while small, is still quite a bit bigger than the K1. For field use, especially backpacking, the K1 is king. The controls are very similar, so a K1 user will feel right at home with the K2. The alignment procedure for the K2 filters though is a pain. That said, once done, you won't have to do it again. People complain about the S-meter, I think it works great. You can lock your frequency, a feature I wish was available on the K1. I haven't played with the memory, scanning and other more complex functions.. That's why I do not want a KX3 or K3, too complicated. Even the K2 could be a bit simpler in my opinion. One thing I didn't like is how later modifications were added to the board without a redesign. Truth be told, the availability of through-hole components is becoming a problem. The K2 is probably on it's last leg. It came out in January 1999, almost 14 years ago! Incredibly, it still holds it's ground with modern rigs. The other problem I see for a QRP, emergency radio, is that the K2 is everything but waterproof. I would even dare to say "water inviting!" It would be totally unusable with the lightest of rain. That's when a good Pelican case is a must.
For a prepping radio, I would rather suggest a K1 or KX1, if you are willing to learn Morse code. The K2 however would be great for anyone wanting to bug-in. Add a solar panel with charge controller, and you're good to go. Always consider that you might have to relocate, and will have more important things to carry than a radio and the associated gear.
Have a great day