A Cool Little Keyer Kit

PicoKeyer Plus

The PicoKeyer Plus makes a good first kit. It has less than 20 components, and once complete, is a useful addition to your shack.

I just received and built the N0XAS Pico Keyer (now the Pico Keyer Plus). It costs only $18 (plus shipping), and is a very cool kit and a useful addition to one’s shack.

As shown in the photo at right, the PicoKeyer measures only 2-in. x 1-1/8-in. On the board, are only 12 components: one resistor, one IC, three capacitors, one switch, two miniature phone jacks, two transistors, a small speaker, and a battery. It took me less than a half hour to solder all the components to the board, and it worked perfectly when I inserted the battery into the battery holder.

The key component is the eight-pin PIC processor. It’s the processor that gives this keyer its flexibility, and it has a raft of very cool features. Some of the ones I like a lot are:

  • Four message memories. You can program up to four messages into the PicoKeyer. To play them back, you have to hold down the switch until the processor cycles around to the message you want. In normal operation, this is not a big deal, but you won’t be using this feature in contests.
  • MCW mode. This is a feature that I haven’t seen on any other keyer. In this mode, the keying output is closed when sending. This lets you use this output to key your VHF/UHF rig, while feeding the audio into the mike input. You will probably still need a pot to adjust the output level, but that’s not a big problem. This is the next thing that I’m going to try to do with this kit.
  • Analog speed control. You can add an external pot to set the speeed. This is a nice feature as doing it via the command mode could take several seconds to do, and that’s really too much time while you’re in a QSO.
  • Battery or external power. You can power the keyer with either an internal battery (the CR2032 show in the photo) or external power supply. To use an external supply, you have to add a capacitor and voltage regulator (not included).

As you can see in the photo, I mounted the PicoKeyer in an Altoids tin. This is the first time I’ve used an Altoids tin for an enclosure, and they really are handy little enclosures.

The PicoKeyer is so small, that there’s room for some other stuff, too. For example, when I use it in MCW mode, I will have to add a small pot. Another possibility is to add a small audio amp to boost the audio output.

Here’s Something Wacky

A mystery station has appeared on 3700 kHz, as well as on 4300, 6500, and 10500 kHz. Dubbed “Yosemite Sam,” the station transmits the voice of Yosemite Sam, Bugs Bunny’s nemesis in the Loony Tunes cartoons saying, “Varmint, I’ma gonna blow yah t’smithereens.” The station cycles through each of the frequencies every 40 seconds, with a transmission every ten seconds. Chuck Sholaut, K6BOG, has posted a page of information and a .wav file of the transmision, go to SpyNumbers.Com.

More Classes?

Recently, one of the guys on the amateur radio club president’s mailing list started a mailling list for hams who teach license classes. The list, dubbed ham_instructor, now has 60 members, and already a few lively discussions have started.

One of the more interesting debates is whether a class should teach students just enough to pass the test or try to give them a deeper understanding of electronics and radio. In addressing this question, Jim Brown N0WE noted that they teach to the test, but also said, “To expand some of the theory, we offer classes that are available to people who are already licensed to concentrate more on a specific topic.”

I like this approach a lot. Getting people involved quickly is a good thing.

Keeping them involved, though–especially when about all they can do at that point is talk on a repeater–is a lot harder. That’s where these classes would come in. Each class would be designed to teach the new hams the basic technology they need to be successful. I would include the followingtopics that I would include in this series of classes are:

  • How Do Repeaters Work?
  • How Do Antennas Work? (Includes building a simple dipole antenna and/or ground plane antenna.)
  • How Do Transistors Work? (Include building a transistor oscillator or amplifier.)
  • How Does Digital Logic Work? (Include building a simple keyer circuit.)
  • How Do I Build Things?
  • How Do I Choose and Install an HF Rig?
  • How Do I Choose and Install a Mobile Rig?

You might also want to have some classes on operating procedures and techniques, including:

  • How Do I Learn the Code and Improve My Code Speed?
  • How Do I Make CW Contacts?
  • How Do I Participate in a Net?
  • What are Contests and How Do I Participate in Them?
  • How Do I Work DX?
  • How Do I Work the Digital Modes?

Of course, the next problem is finding people to develop and teach these courses, but that’s not impossible. And once the courses are developed, they can be used over and over again.

Fixing a Small Boat Anchor

About a month ago, I found out that our club had a 60s-vintage Heathkit HD-10 Keyer that someone had donated. The only problem, according to our technical director, is that it didn’t work. He did, however, have the manual. Well, especially with the manual, I didn’t think it would be much of a problem to get it up and running, so I told him to bring it to a club meeting, and I’d take a look at it.

The first problem I encountered is that while it did indeed come with a manual, it wasn’t the right manual. The manual was for an HD-1410, not the HD-10. It looks like the HD-1410 is the HD-10′s younger brother. For one thing the HD-1410 has built-in iambic paddles, not the single lever of the HD-10.

So, my first task was to find a manual for the HD-10. This turned out to be a lot easier than expected. The manual is available from the Boat Anchor Manual Archive (BAMA). Actually since traffic on that server is limited, I downloaded it from the mirror site. I didn’t get the whole manual–more about that later–but what I did get included the theory of operation and a schematic.

The schematic of the HD-10 is, of course, much different than the schematic of the HD-1410. While the more modern keyer uses integrated circuits, the HD-10 circuit consists of 12 transistors, with the accompanying resistors and capacitors. In a way, that makes the HD-10 much more interesting to work on. I graduated from college in 1978, and by that time, very little time spent teaching how to build logic elements from transistors. Mostly, we concentrated on how to apply ICs, unless you took semiconductor design courses.

The HD-10 consists of a multivibrator to generate dots, a flip-flop used to generate either dots or dashes, and a driver to key the transmitter. There’s also a second multivibrator to generate the sidetone. A pot controls the frequency of the dot-generator multivibrator, which then control the character rate of the keyer.

One nice thing about this design is that the power supply voltage is not that critical, and Heathkit was therefore able to include a simple AC supply. It consists of a small transformer, a couple of diodes a resistor, and three electrolytics. It supplies voltages of +19 V and -16 V. The weight of these components helps anchor it when using the built-in single lever paddle.

I skimmed over the theory of operation and examined the schematic for 10 minutes or so, then dug into the keyer. I was never impressed with Heathkit’s packaging design, and my experience with the HD-10 did not change my mind at all. I removed the screws that held the front panel to the unit, but because of the way the cabling ran, I ended up scratching the case. The cables were not long enough to allow me to move it away far enough.

That exposed the printed circuit board, but the board was mounted upside down and there were no markings on the bottom of the board to identify the components. That meant I had to also remove the PC board, which was mounted on four long spacers. Once I removed the screws, I once again had to carefully arrange the front panel, PC board assembly, and base unit so that I could probe the circuit without shorting anything out.

Once I’d done all that, I started poking around. The well-written theory of operation made this a lot easier. It shows waveforms at various points and probing around, it looked to me like everything was working correctly. Why then, didn’t I get a sidetone?

It turns out that the HD-10 has a terminal strip on the back that lets you connect your receiver’s audio to the keyer, and then listen to it either with the keyer’s speaker or with headphones plugged into the keyer’s headphone jack. Why would you want to do this you ask? Well, back in the 60s–when this keyer was being sold–one normally used separate receivers and transmitters, and the transmitters usually did not provide a sidetone. This feature of the HD-10 allowed you to both listened to received signals and monitor the code your were sending.

The kicker is that if you were not going to use this feature, you had to ground the RCVR AUDIO terminal to ground. Once I did this, the sidetone was loud and clear. The end result was that it took me about an hour to disassemble the keyer and play around with it only to find out that I hadn’t configured the thing properly. Something that I could have possibly avoided had the manual on BAMA include operating instructions.

Reassembling the keyer took another half hour, mainly because I didn’t get it right the first time. The first time I tried it, I forgot to add nuts between the spacers and the PC board. Without the nuts, the board was not high enough, and something was shorting a connection on the PC board. I had to remove the board, add then nuts and then screw it down again. Finally, however, I got everything back together, and it seems to be working just fine.

Yet Another Cool Thing to Build

When I’m tuning around looking for a QSO and hear someone calling CQ, I’ll often type their call into QRZ.Com to see if they’ve input any biographical information about themselves. Yesterday, I heard N5IW call CQ and called up his QRZ.Com page. On it was a link to his home page, where he as a bunch of interesting stuff. The first thing that caught my eye was his Resonant Speaker project.

Using simple plastic plumbing parts, N5IW shows you how to build a tuneable resonant speaker (shown at right) for CW work. The theory is that you’re creating a cavity that’s resonant at a particular audio frequency. Audio at that frequency passes right through the cavity. Other frequencies are blocked.

I’ve seen several articles like this in ham mags over the years, but this is the first one that actually looks simple enough for me to build. Next time I’m at Home Depot, I think I’m going to pick up the parts.

Skywarn Recognition Day

I just finished participating in Skywarn Recognition Day. Like most events of this type, it’s easy to get sucked in. At first, I thought I’d just work a couple of stations, but one led to two, two led to three, etc. Overall, I worked 11 stations in 9 different states:

  • WX2OKX – Upton, NY
  • W9S – Chicago, IL
  • WX2PHI – Mt. Holly, NJ
  • WX2BUF – Buffalo, NY
  • K0DMX – Des Moines, IA
  • WD9CIR – Lincoln, IL
  • KC0NWS – Kansas City, MO
  • WX4MLB – Melbourne, FL
  • WX9ARX – La Crosse, WI
  • W0NWS – Omaha, NE
  • N0Y – Aberdeen, SD

It was a nice event celebrating some of the best public service work that hams do.