More QSOs

I've now been on the air with my K2 for about two months, so I thought I would post some comments about the QSOs I've made in that time. 

After my first couple of voice QSOs I started to understand why a lot of SSB phone mode operators run hundreds of watts of power. An SSB voice signal is about 3kHz wide. PSK31 is 31Hz wide, and CW (Morse code) is narrower still. Once I realized that there's a correlation between signal bandwidth and power required, it made sense why non-voice modes were so popular and have persisted for so long in almost every area of radio other than commercial broadcasting. 

I'm still lousy at copying Morse so I didn't want to spring for a >$100 key just yet. I had borrowed my friend Nick's cheap-o White Rook paddles, but he wanted them back, and new ones were backordered 5+ weeks (though I did place an order for one anyway to get the ball rolling). If I was going to use digital modes I was going to need an audio interface to my Mac laptop and a way to key the rig. In the end I home-brewed an incredibly simple circuit to do just that. It's nothing more than a voltage divider to step the line-level audio down to mic level, and a toggle switch to key the radio. The input is a 3.5mm headphone jack and the output is a standard 8 pin mic plug. With this and the FLDigi software on my Mac I was able to start making data mode contacts.

As it happened, completion of this interface coincided with me needing to spend a few hours hanging around my rowing club. I had been thinking that setting up a wire antenna there, with its proximity to San Francisco bay, could make for some great operating conditions. I strung a wire from our second-story balcony about 50' down toward our dock and tied it off to a convenient pole. Then I made a horizontal counterpoise that was… not very long… and hooked this up to my manual tuner. The only band I could get it to tune well on was 20m, but as it turned out, it was jumping with signals so that was fine! After a few attempts at making QSOs, I realized that I had no idea how to use FLDigi! I was hearing signals from all over the US, and a few of them heard my replies but then I couldn't figure out how to carry out an actual conversation! I spent some time reading the manual, but eventually had to go home without much real success.

 It didn't take long for me to get the hang of FLDigi though, and since then I've made quite a few PSK31 contacts (and a few Olivia ones too). Most of my contacts have been confined to the western US states, but I've also gotten Hawaii, Georgia, and Montana. I've heard very few stations south of the border, and with only 5 watts and this "compromise" antenna setup, I'm not likely to get out too far. With luck I'll get access to an amp again soon that will help with the power output, but the antenna is going to be a problem for the foreseeable future. Still, I'm on the air and making contacts! Life is good! I got a SignaLink USB interface for Christmas, so now I don't have to manually key the radio any more (or worry about accidentally transmitting any Justin Bieber MP3s). All I can do is wait for the bands to be open and hope for the best.

Up next: trying to learn Morse code!

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Final thoughts on the K2 build

It has been a few weeks since I finished the K2 and its SSB board, so I thought I would write down some thoughts for the benefit of other builders.

First, I have to say that my "measure twice, cut once" approach was probably the biggest contributor to my success. I can't stress enough how important it was for me to do the full parts inventory before I started building – I was missing a couple of parts, and Elecraft quickly shipped them to me. I was still able to start building without them, and then I wasn't brought to a standstill later when I got to where they were needed. I double checked each part before placing it, making sure I had the right value, polarity, location etc. And I also checked the board carefully with a magnifying glass before powering it up. On more than one occasion I found parts I hadn't soldered, including an entire IC!

Investing in some good quality tools was also a really good move. The best of the bunch was the Panavise 324 "electronic work center." It's basically a weighted base with two clamping arms that can be adjusted to different widths to hold most PCBs (anything larger than maybe 2-3" wide). With the PCB clamped in, you can have it right side up while you insert parts and bend their leads back, and then quickly turn it over to solder it. It also has 6 parts trays in the base and a solder spool holder. I got that on Amazon I think. I also bought a set of diagonal flush cutters (totally invaluable), a set of different-shaped tweezers, and a set of small screwdrivers, all from Jameco. I was fortunate that my friend Nick was willing to lend me his Metcal soldering station, but I think one of the nicer Wellers (temperature controlled, blue wand) would have worked fine also.

Despite my best efforts, I did make some mistakes building the K2. The first two were on the RF board. After completing it I followed the instructions to align the transmitter, and found that I couldn't get more than 400 mw of power on 40m no matter what I set the power dial to. The first mistake I found, while inspecting my work, was that I had wound the toroid T4 improperly. It uses a binocular core, and the two "linking turns" for it are supposed to just go straight through each hole. I had wired them each through BOTH holes which, I realized later, was stupid because you use bare wire for these. Everything was shorted! But I fixed this and my output power problem remained.

There are 3 holes at the point where C6 is installed. If you are installing the 60m board, a 3 pin header goes there instead. Otherwise, the capacitor's leads need to go in the outer two holes, leaving the center hold empty. I misunderstood both the original instructions and the errata that was supposed to clarify this, and as a result I couldn't get more than 400mw output on 40m. Eventually I fixed this and, miracle of miracles, the K2 worked!

This brings me to the last thing I want to comment on – the wonderful Elecraft mailing list. In addition to official telephone and email tech support, Elecraft also has a mailing list where users of their products discuss them, as well as other (sometimes) related topics. Whenever I had difficulty with the K2 construction, I either searched there and found the answer, or posted a question and got a response quickly. In particular, Don Wilhelm, W3FPR, was a huge help. He was often the first to reply and often had the right answer on the first try.

All in all, the K2 was really fun to build. I started to learn about the electronic theory behind radio, what you need to make one work, as well as just some simple mechanics of kit building that will be useful to me going forward. One of my goals in getting into ham radio was to have an excuse to get BACK into electronics and kit building, so the K2 project has really satisfied that. It has given me the confidence to always want to ask, "Can't I just build one of these myself?"

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First QSOs!

I made my first real QSOs with the K2 this week! Last weekend Rob (AK6L) and I did some experimenting trying to make contact on various bands, and finally had success on 40m. Given that he just lives across the bay in Berkeley, it made sense that 40m worked because my loop antenna is 42 meters long. Theoretically, a loop that is less than 2 wavelengths will mostly radiate upward, whereas one that is 2 or more wavelengths long will radiate more off the sides. So on 40m I have a "cloud warmer" that causes signals to come back down near me. Good for local contacts like Rob.

At that time I was trying to use a PC headset mic that I have, with a pre-amp circuit that I cobbled together, and he said he couldn't hear any treble in my voice. After that I resolved to take vice grips to the non-standard connector on the mic he gave me, get the damn thing off even if I ruined it, and then wire up the standard connectors and cable that I had bought. It turned out that the 8 pin chassis connector I bought was too big for the hole on the mic base, so I hard-wired the new cable and female connector. I'll just need to get some strain relief for it.

Yesterday I was tuning around on 40m and I heard what sounded like an old man net – three or four old guys talking about brushing their teeth, doing chores, and one talking about putting on his artificial leg (it uses suction to stay attached). During a break in the chatter, I keyed up and said, "KJ6AKQ looking for a signal report…" One guy said, "…what?" Another said, "Sounded like he was looking for a signal report – there's a bunch of us out here, but go ahead and jump in if you want!" So I said, "I'm surprised you can hear me but I'd love a signal report if possible." He replied, "This is N6UGY, I'm in Red Bluff, California. Go ahead and transmit for a bit and I'll give you a report." So I told him that I'm in San Francisco, using a new K2 that I just completed, only putting out 15 watts, and using an antenna that I expected to be pretty inefficient. He said that he had about S7 noise and I was fading in and out of it, but copyable. "I'd say you're doing pretty well for 15 watts!" So I thanked him and checked out, not wanting to slow them down with my weak signal. San Francisco to Red Bluff is around 175 miles away, but that's a good start!

Today my friend Joe (N1QD) in Boston IMed me to say that 15m was open to CA right now. 20 was looking open also, but although we tried both we weren't able to make contact. Tuning around, the bands were jam packed, and it turned out that this weekend is the ARRL SSB/phone Sweepstakes contest, so everyone was out in force. I was hearing CT, VA, and lots of other states as everyone tried to rack up points. I tried to QSO with one guy in Calgary but he couldn't hear me. After doing some chores and coming back, I heard KL7RA in Alaska calling CQ on 20m and tried him. He heard me right off the bat! I had to repeat my call a couple of times for him to get it, but then we exchanged contest info no problem. San Francisco to Kenai, AK is 2024 miles! With 15 watts and a crappy antenna! Wow… I am hooked.

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K2 build project: RF board part 3

This will be the final construction post about the base K2! I officially finished it on October 8th by installing the speaker and affixing the serial number sticker to the back of the case. K2 #6991 is born!

The final phase of construction had me installing a bunch more discrete parts, winding the last few toroids, then aligning/calibrating the receiver before I installed the speaker, buttoned up the top of the case, and added the serial number sticker. 

During the alignment phase, I discovered two mistakes. The first step is to align the transmitter on 40 meters. The manual says to set the output power to 2 watts, put the transmitter in tune mode, and adjust two inductors to get the peak power out. Unfortunately, in tune mode I was only seeing 300-400mw, and adjusting the inductors didn't have any effect. During my first visual inspection after uncovering this issue, I realized that I had misread the directions for winding T4, a transformer with a binocular core. I decided to wait until the next day to correct this mistake, because it had gotten pretty late by this time. I came home from work the next afternoon, fixed the T4 windings and put everything back together, but I still couldn't get any more power out on 40m.

My next step was to email the Elecraft email list, and I got a response from Don Wilhelm, W3FPR, less than 8 hours later. After two days of troubleshooting we figured out that I had put C6 in the wrong place on the RF board. There's even an errata about this step, which I dutifully copied into the manual before I began building, but it still wasn't clear enough for me. The issue is that there are 3 holes at the location where C6 goes, and the cap needs to go in the outer pair of holes, with the middle hole left open. Apparently the errata sheet is being updated AGAIN, with a picture this time, to clarify this step once and for all! Once I fixed this I immediately started to get good power out on 40m, and I proceeded through the rest of the alignment procedure with no issues.

Once the alignment was done I put the final cosmetic touches on the rig and it was done! As of now I've spent a number of nights listening on the different bands, getting familiar with the K2's controls and learning my way around the bands. I still don't have a proper antenna setup yet so I have not tried to transmit. Hopefully that will change soon. I also still need to assemble the SSB board, and cobble together a mic cable for the Kenwood MC-50 mic that my friend Rob, AK6L, gave me. Then I can make some voice QSOs, and if I get a SignaLink PC interface I can work some digital modes too. More to come on all this.

 Last of the capacitors and resistors installed.


Transistors and inductors added.


Several more toroids.


All done and installed in the case.


Affixing the serial number sticker.


WWV comes in loud and clear!


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K2 build project: RF board part 2

Life has intervened a bit lately, and I've had less time to work on the K2 than I would like. I've slowly plodded through the second phase of RF board construction, and last week I was able to see the fruits of my labors. I put everything back together, powered it on, and did not see smoke! Furthermore, after working through the alignment procedure, I was able to hear CW on 40m with a 10 foot length of speaker wire as an antenna! That was really gratifying. I originally wanted to post an MP3 of that, but I ended up impatiently pressing on with the third and final phase of the board, which is now nearly complete. The following photos are just phase 2.

This board is a retrofit that adds thermistor discipline to the K2's PLL, for a more stable clock.


Thermistor retrofit installed in the lower left corner.


Lots of capacitors installed.


Test points (yellow pegs) and crystals installed.


My first toroid.


Everything put back together for testing at the end of phase 2.


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K2 build project: RF board part 1

The RF board of the K2 is the most daunting part of the build. It has the most components to install, and also requires the precise winding of quite a few toroid inductors, which I've never done. A lot of people seem to quiver in fear of winding toroids, but everyone I know who has done it says that it's really not that hard. The important part is to just take your time and keep an accurate count. I had the option to pay extra for pre-wound toroids for the K2, but I decided to man up and do it myself.

As of now I have finished phase one (of three) of the RF board assembly. At this point you get to put the RF board together with the front panel and control boards, power it all up and do some testing. At this stage we make sure the relays and rotary encoder are working, we test the audio amplifier and tone generator, we try out the keyer, we set the AGC threshold and align the S-meter, and we make sure the S-meter is drawing the right amount of current. The toroid winding starts in phase 2. Here are the pictures of my progress so far:

Latching relays, a socket, and spacers (on the bottom) installed.


Keyer and headphone jacks, antenna connector, power switch, header pin sockets, and various other components installed.


Side panels attached.


Now it REALLY starts to look like a radio!



The K2 includes a built-in frequency counter for testing. We assemble its probe and test it out at this point. Phase 2 of the RF board starts tomorrow, I hope!


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K2 build project: Front panel

Sorry for not updating again sooner, I've been making steady progress on the K2 but, when faced with the choice between spending an hour writing a blog post or an hour working on the K2, the K2 wins!

The front panel went together very easily, both because it has fewer parts than the control board, and also because my rusty soldering skills have gotten back up to par (at least by my standards). Now, a couple of weeks in, when I look at the control board I'm a little disappointed. That row of transistors doesn't have a uniform height! But Nick, my EE buddy, inspected my work and gave it a thumbs up, so that's a good sign.

The front panel consists of all the buttons and knobs, headphone and mic jacks, the LCD screen, and the S-meter. The LCD is actually pretty tricky to install. I'm not sure if this is common or what, but the LCD and the backlight were totally separate units. The backlight consists of two LEDs at either end of a glass diffuser with a special paper over it to help diffuse the light. You mount this first, on its LED leads, using spacers made out of scrap PCB so it stands off the main circuit board by 1/8". Then the LCD straddles the backlight, and you solder all its pins afterward. It took me quite a bit of careful assembly to get these right, but I knew I needed to take my time to avoid having a sub-par display.

The rotary encoder which makes up the brains of the tuning knob is pretty neat. I mean the encoder itself is nothing special, but Elecraft gives you a felt washer that goes around the tuner's axle, between the plastic knob and the front panel itself. This is to provide some friction against the knob so that when you spin it it doesn't keep spinning forever. Love the attention to detail! And now, some photos:

First we install the buttons.


Mic jack, S-meter, socket (on back), various microcontrollers and other components.


My wife took this one of me soldering.


Trim pots, LCD and backlight, and key caps added.


Everything mounted in the front panel casing! I definitely spent a few minutes turning knobs and pushing buttons and making CW sounds after reaching this point. I'm not gonna lie. The RF board is next!



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K2 build project: Parts inventory and control board

Having read a couple of blog posts that other people wrote about assembling K2s, and having read the introduction to Elecraft's wonderful assembly manual, I resolved to take a "measure twice, cut once" approach to building my K2. With that in mind, the first order of business was to do a full parts inventory and make sure nothing was missing.

Elecraft makes this pretty easy by providing all the resistors you need, in order, in tape reel form; putting the parts in separate bags for each phase of construction; and providing a nice appendix inventory of all the parts, with helpful photos, divided up by phase. This almost aligns perfectly with the bags, except that the RF board parts are in two bags, and the inventory doesn't specify which will contain a given part. I just inventoried one bag, then made sure all the remaining unfound parts were in the other.

In the end, I was missing one set of header pins for the control board, and one capacitor for the RF board. A quick email to, and I had the replacements 2 days later. They didn't even impede me from getting started with the construction.

The control board is the first phase of the build, and Elecraft's construction manual proved itself right off the bat. It's just incredibly well-written, clear and unambiguous. It has you install components in groups, and in an order that keeps you from painting yourself into a corner. For example, it starts with all the resistors. The first step is something like, "Install R5 (orng, orng, orng). Bend the leads so they fit through the holes. Mount it with the tolerance stripe down for easy reading later. Solder it and trim the excess leads." Then step two is basically, "Now mount all the other resistors in the following order…" So the first step for a group of parts gives you some tips on working with them and has you start with one, and then subsequent steps walk you through the rest.

The control board construction was pretty straightforward, and I finished it in about 6 hours. Here are some photos that show the board taking shape. You can see high res versions here.

This is my workspace, with all the K2 stuff laid out. Once I got started I cleared away more space so I only had the parts I needed right at hand. On the left is the K2 assembly manual. At center, the Panavise workstation. Center/bottom is RF board for the K2, to be assembled later. On the right, a so-so Weller soldering iron; I later borrowed a Metcal from my friend Nick, which I'll use for the rest of the build. All the stuff in pink bags is K2 parts.


Resistors installed, not yet soldered.


Closeup of resistors after soldering. My joints got cleaner as I went along.


Resistor networks installed. I had never worked with these before.


Small value capacitors, trim pot, and shielded inductor installed. I also flipped the orientation so that the Panavise jaws didn't squash the resistor network on the right side.


Electrolytic caps installed plus bonus artistic depth-of-field shot!


Bipolar transistors installed.


Voltage regulators and crystals.


All done! PIC, various op-amps, and header pins all installed. Everything checks out under test for now; more extensive testing will be done when the front panel board is finished. That's up next!


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K2 build project: Introduction

For those of you not following along at home, I passed my Technician and General license tests over a year ago, having wanted to become a ham since I was about 13 (but never having followed through on it). In the intervening time, I have done precious little operating.

Ham radio appeals to people for a variety of reasons; it's a hobby with a lot of different facets. The two that appealed to me were making HF contacts over long distances, and building my own equipment. When I was in high school I took some electronics classes and learned the fundamentals, but I've long since forgotten them. I also ran an FM pirate radio station (*guilty face*) and built a transmitter, amplifier, and stereo generator from kits. That was the last time (12-13 years ago) that I did any serious electronics work though.

After getting licensed, I spent some time looking into possible HF rigs. My friend Nick loaned me his Norcal 40A QRP CW rig, and my friend Rob loaned me an HF amp that I could use with it. I got good enough at morse code (and found other hams with enough patience) to make three QSOs with these and a somewhat crappy dipole. I also bought a Yaesu VX-7R HT, with the intention of chatting up the local hams on repeaters and using it to make some satellite QSOs. But the diplexer I need to make my home brew satellite antenna work remains unbuilt, and it turns out that most of the local repeaters I can hear are little-used and rather boring. Limited to 40 meters, and with my wedding looming, the HF rig fell into disuse as well.

I decided pretty early on that the Elecraft K2 would be the best full-fledged HF rig for me. A lot of people ask, "Why not a K3?" The reason is that the K3 is basically a Lego radio – it's an amazing piece of equipment by all accounts, but assembly just involves snapping some pre-built boards together. I wanted a kit that would have me melting solder, burning my fingers, and squinting myself into early onset myopia. The K2 fits the bill nicely; it's moderately challenging, probably more so for me since my soldering skills are so rusty, but I'll have some help from friends as I go.

The aforementioned wedding, and then an immediate move to a new apartment, stopped me from ordering the K2 sooner. Then in June, for my 30th birthday, my wife "gave" it to me, but it came with strings attached! I couldn't order the kit until I got my old car put up for sale on Craigslist and got our TV antenna working to her satisfaction. I knew I married a smart woman, but I didn't expect it to bite me in the ass!

Two weeks ago I finished these chores, ordered my K2, and serial number 6991 arrived a few days later (if only I could have gotten #7000!). I also bought myself a Panavise 324 electronics workstation, an anti-static mat, a set of various types of tweezers, some small screwdrivers, and a nice diagonal flush cutter. I'm off work all this week, so I've started the build and will be documenting it here. Stay tuned!

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Retro ham radio

Someone on #hamradio posted this today:


LOVE it. The guy's wife is bringing him a Miller (note the label) on a tray with a glass, and his chair cushion totally has his call embroidered on it. And you know the beer glass is frosted also. He doesn't drink beer out of an unchilled glass like a savage. This is how I envision ham radio : )

I've gotten no operating done lately, not even listening to sats. I still haven't finished the diplexer for the IOio antenna. I just finished moving to a new apartment though, and the unpacking is nearly done. I want to get the IOio project finished soon, and then think about putting up a new HF antenna. After some investigation, I think I'm going to try putting up a 120 meter sorta-loop. If I'm lucky, I should end up with something that is usable on 80-10m. If I'm not lucky, I will probably suck it up and just get a buddipole, and set it up when I want to operate. I don't think it will be feasible for me to set up a regular wire dipole at my new place without pissing off the landlord.

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