Maximize my power and make it so the first time

I built the Elecraft K2/10 transceiver during the summer of 2012 while recovering from knee surgery. It was by far the most ambitious kit I had undertaken and being condo bound, it was a perfect bucket list project to start and complete.

Truth is I’ve always had a “thing” about the K2 as its such a well respected analog radio that delivered performance comparable to off the shelf radios costing 2-3 times more. Being a condo dweller operating from within was a non starter and my haste to get into the field and hiking sooner than I should have, cost me dearly. That plus the advent and arrival of an Elecraft KX3 made the K2 a bit of an orphan. The few times it’s been into the “wilderness” its done remarkably well including a summit to summit (the first) from the USA to Australia or in a newly minted Monument alone and seemingly surrounded by meth labs. Given the variability of antennas and the need for expedience, an antenna tuner can be a god send allowing a radio to deliver it’s maximum output. We all want that, don’t we? And so it is that I had rummaged through my collection of unbuilt kits (it’s a large collection) and pulled out the K2/100 companion antenna tuner, the KAT-100.

Elecraft kits (which are dwindling in number, so get them while you can!) come with remarkably well written construction guides. Pictures, step by step instructions and eventually test, alignment and troubleshooting steps all differentiate an Elecrtaft kit from many others. Not cheap but you are getting a great experience and product and presumably paying it forward by funding future development.

I’ve met some of the Elecraft team, at ham conventions and even on field trips to the Watsonville factory but Stephanie is a mystery angel. She seems to have packed the vast majority of the parts for my kits and never seems to screw up. Everything expected is present which when making a kit the alternative could be understandably frustrating. Thanks Steph!

Here Wayne, the Elecraft K2 designer explaining the virtues of the KX2

I started the KAT-100 build before leaving for Costa Rica and really didn’t get too far. Sorted the capacitors and resistors, thanked Steph and soldered a few in and before I know it six or so weeks have gone by including a trip back to the UK to be examined and presented.

KAT-100 is the skinny unit below my Elecraft K2 moments before being put to the test in my backyard

I enjoy building kits and its as much about the journey as the destination. No point rushing and definitely no point cutting corners or being sloppy. Its much harder to find a failure once the kit is completed and so I spend time sorting parts, testing values and even testing continuity to verify a solar joint in functional.

Verifying component values and in this case of resistors
Labeling and sorting parts makes the build more efficient and less frustrating

and so by the time I was getting ready for Costa Rica I had really only stuffed capacitors in the the KAT-100 main board.

No very far along by the time I was Costa Rica bound

Costa Rica was an eye opener and looking back I see many areas that we could improve our efficiency. No doubt the KX3/PX3/KPA100 is a fabulous combination and right up there with the best of the best but I really don’t like having three separate units with a bunch of wires connecting them. The smallness of the panadpter screen (PX3) and especially the inability to peak into anymore than one band at a time doesn’t seem efficient either and then our whole antenna cabling etc was a little ad hoc.

KX3/PX3/KXPA100 portable contest station. Works great but could the K2 be the basis for a better solution?

So lots of ideas bouncing around including using the K2/100 as the station which predicates the need for the KAT-100. So home again and I’m feeling even more motivated to get the KAT-100 completed.

Toroids wound, relays installed, chips ahoy and the KAT-100 main board looks almost complete
Toroid winding (particularly the number of turns and wire distribution) is aided with the manual pictures
Snuggly anchored to the board
18 relays and 90 pins that Elecraft do not want you to trim
Front panel assembly
Extra care needed in lining up the front panel LEDs
IMG_0529 (1)
Soldering the front panel connectors to the main board
Front panel mated to the main board
Back panel mated to main board
Board verification and alignment only require a volt meter – easy!!!
Alignment is simply about turning trimmers like C31 and watching the volt meter
First contact at 100 watts through the ATU with Mary WA0CSL in North Dakota


Twiddling the tuning knob (the big one under the digits in the picture above) I happened upon Mary WA0SCL working the North Dakota QSO party. Perfect! North Dakota isn’t on the air that often and she had a pretty good signal despite variable propagation. So at 19:24 UTC on Saturday April 14th my new KAT-100 seemed to do its stuff and allow me to pump a full 100 watts into my antenna where previously I’d be lucky to get 50 watts before an SWR mismatch had the K2 rightfully complaining.

I love it when it works first time…..makes up for all the times others didn’t!





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