Two sessions ... and RFC1 and D1/D2

I had two good build sessions, one yesterday and one today. This post will show two progress views and two build details that I thought were worth documenting. First, the progress views:

	Here's the main board at the conclusion of yesterday's build session.
	Here's the main board at the conclusion of today's build session.

Yesterday's build session encountered the only two somewhat tricky part insertions so far.

	The leads to D1 and D2 need to be bent to 90° right at the body of the diode. Even bending the leads really close to the body, I was unable to get the diodes to sit totally flat again the board (although I got it pretty close).
	The instructions for mounting RFC1 read "[the choke] has very fragile leads. Do not pull them." It goes on to warn again excessive soldering time. Well, RFC1's length exceeds the spacing for its mounting holes. I didn't attempt to get the part really close to the board. The picture shows my mounting solution.

Next ... two more toroids to wind, tin all the leads, and move on to mounting L1 to L8.

Resistors and capacitors and C31

The 7 missing capacitors arrived in the mail yesterday (thumbs up to Elecraft parts folks and the USPS!) and I got back to soldering last night.

The main board is now populated with all its capacitors and all its resistors (with the exception of one resistor on the bottom of the board to be inserted first the next time I fire up the soldering iron). This board sure is spacious!

The directions for inserting C31 read "Orient the flat side of the trimmer as indicated." The indication on the board was clear enough, but, judging from the shape of the part, I wasn't sure which side was the "flat side." Fortunately, Google image search came up with a recent (2010) hi-res picture of the KAT100 main board that clearly showed how C31 (same form factor) was mounted. This detail shows the result.

While waiting for the capacitors to arrive, I wound L1 to L6. It's really easy working with these large toroids and number 20 wire. I've found in this, and previous projects, that winding the toroids is one of the more enjoyable aspects of the project.

Just started on the KAT100-1

For this year's project, I've decided to build Elecraft's companion antenna tuner for the K2, the KAT100-1. The kit arrived by UPS a few days ago, and I did a complete inventory. The kit was missing the 7 150pF 2000V capacitors, but was otherwise complete. I wrote to the parts folks on Friday, got a nice email back almost immediately, and am expecting the parts to show up in a day or so.

	Here's the obligatory picture of the first installed part, C55. One thing that struck me, having built the KSB2 last year (have a look at my blog posting from just a year ago), is how roomy the KAT100-1 board is!
	Here's the main board populated with almost all of the capacitors. What's left are the 7 missing capacitors. I like to follow the build order pretty strictly, so I'm now waiting for the caps to come in the mail. In the meantime, I'll probably wind a few of the inductors in my next build session.

The large number of capacitors went in really quickly. The leads for all the caps, and their corresponding holes in the main board, all had the same spacing, so no bending/forming of leads was required; this was a welcome time and effort saver.

Almost done ...

I managed to get in some very good construction sessions in the past couple of days and have almost finished up stuffing parts into the KSB2 board. I thought I would post some pictures that folks might find useful.

	Here's a view of the bottom of the board; that's where all but one of the resistors are installed. The instructions for prepping the resistor leads and installing the parts were excellent. Overall, I'm finding the KSB2 build instructions to be about the best I've seen from Elecraft so far.
	Here's a close-up of the crystals, installed and grounded. Here again, the instructions for grounding the crystals were very good. I also referred back to my posting here on grounding the K2's crystals, which was still helpful.

All that remains to be installed on the KSB2 board are the two transformers and two RFCs; these are all wound and ready to go. Next following that is opening up the K2 and modifying the RF board to accept the new plug-in board.

Capacitors, Diodes, Resistor Networks

I've managed to put in a small number of hours over the past several days and the project is coming along, as usual, slowly but surely. I'm still checking each component's label and placement on the board two or three times before soldering, and then checking each soldered connection immediately.

Over the weekend, while waiting for the two missing parts to arrive (which they did in the morning USPS delivery on Monday), I wound T1 and T2, so they will be ready when I get there.

You can see in the picture that there were a large number of the small blue caps to be installed; fortunately, for all of them, I was able to follow the initial instruction, and didn't have to bend their leads at all.

Diode installation was no sweat. The instructions were very clear. The right side of the board is so crammed that several of the diodes were not labelled on the board at all, but were very clearly marked in the pictorial in the installation manual. The "check it twice" method caught the fact that I had initially put D4 in in the wrong direction; the cathode goes up, not to the right.

Here's what the KSB2 looks like so far. The right side is crowded. The holes for the cathodes of the two diodes at the extreme right side of the board are actually right at the edge of the board.

Transistors next ...

Adding the KSB2 SSB Adapter

A bit more than a year has gone by since I completed building the KPA100 and the building bug has bit again. I spent a big chunk of this winter someplace warm and I brought my K2 (sans the KPA100), and kind of wished I had had voice capability. So, I decided to add the KSB2 SSB Adapter to my K2.

The kit arrived by UPS yesterday in the late afternoon, and I did the inventory last night. The kit was complete except for one capacitor and one resistor; I wrote to Elecraft about it last night, and the parts have already been shipped as I write this (thanks, Elecraft!!).

Here's the kit, sorted into a variety of containers, and ready for assembly. As you can see, there's really not a lot of parts to this kit. However, as you can see here, the adapter board is pretty small, and there are a lot of small capacitors and 7 crystals, etc., crammed into a pretty small space. Should be interesting!

The KSB2 board is Rev. G, dated 2011. I started construction this afternoon; I couldn't get too far because the missing capacitor is one of the earliest parts to be stuffed (and I really don't want to get ahead of the assembly instructions). Assembly is prefaced with a comment about not needing to straighten the leads on small capacitors, but also to keep them no more than 3mm above the board. However, as the leads were formed on C30 and C36, there was no way the capacitors would be that close to the board; so I straightened the leads (and fortunately did not break them!).

KPA100 Completed!!

I haven't posted here for a while, but I have taken a few pictures along the way. Now that the project is done, I thought I would catch up here.

	Here's a look at the KPA100 board after the last component had been stuffed, and before mounting it on the heat sink/K2 cover. I put the big 800° tip, the one I use to assemble dipole antennas made out of #14 wire, on my Weller to solder the power transistors to the board. That did the trick very handily.
	When assembling T1 and T2, I scouted around the Web looking for pictures. I found some which were helpful, but I decided to take the pictures I wish I had found. This one shows the detail of how T1 was soldered to the board.
	Here is a detail of T2's installation, showing both how it is soldered to the board and, in particular, how C83 is mounted on T2's metal frame.
	Here is the final alignment and test setup. All procedures in this section of the manual went fine. I made one contact on 40 meters in this configuration. It also became immediately clear as I tested transmitting on the various bands that the KPA100 is quite sensitive to SWR. At this point, I reconfigured my good old Heathkit antenna tuner, which I had just been using to tune my 80/40 meter random antenna, to now tune all my dipoles as well. With SWR now 1.0 to 1 on all bands, the KPA100 happily ran at 100 watts with no power reduction.
	Here is the completed K2/100, with the antenna tuner now located in a more convenient place. I made a couple of contacts on 30 meters (HB9 and F5) and ran upstairs to get the camera!

So, I'm at the end of my Elecraft kit construction, for a while anyway. I'll see how the ARRL CW DX contest goes next month, and maybe look into building the KAF2 later this year.

I did not enjoy building the KPA100 to the same extent that I did the K2 and mini-modules. I found it to be fairly grueling, but I'm not sure why; maybe I just needed a longer break before starting construction, or maybe I needed to do it without the February contest staring me in the face. However, the KPA100 works fine "out of the box", and demonstrates again that Elecraft manuals are first rate; you just need to follow the instructions carefully (and especially so when an instruction is in bold font).

Constructing the power cable was a nightmare. Fortunately, this posting to the Elecraft K2 list provided some really helpful hints, especially about installing the fuse connector; I don't think I could have done it without Jay's suggestions. If I were to do this again, I'd buy the pre-assembled cable from Elecraft.

I'd suggest one change to the K2 build that would make KPA100 integration easier, and that is I would include P3 and P6 (RF and power connectors) on the K2's main board as part of the standard K2 build. I don't know what the statistics are on how many K2 builders go on to build the KPA100, but it sure was a nuisance having to disassemble and re-assemble the K2's heat sink to mount these two parts. I would have much preferred to install them as part of K2 construction.

There were no problems with clearance of all those capacitors on the bottom of the board; they all cleared the back of the heat sink with ample margins.

Two surprises: while doing the inventory back at the beginning, I discovered that KPA100 provides a DB9 serial port, allowing the K2 to talk to my computer. I built the serial cable last night and, sure enough, CTWIN can change bands on the K2! The other surprise came up fairly late in construction, and that is that KPA100 provides an on-board SWR bridge and metering. So, my recently built W1 is now off-line. However, I was still glad I built it, since I used it to calibrate the power and SWR metering on the KPA100; it was very handy reading exact power and SWR measurements on my PC!

Thanks to the parts and support folks at Elecraft for their fine help during construction. And thanks as well to Don, W3FPR, for his friendly and very informative support.