I have read that there is a declining interest in operating the CW mode.  CW is my favorite mode and I spend approximately 95% of my operating time devoted to pounding brass.  I recently had a QSO with a 15 year ham who was newly licensed and operated CW ONLY.  That sure was refreshing.  In spite of the deregulation of our rules and reg;s, or possibly, because of these changes I have met several operators who are new to CW and are trying this mode for the first time and enjoying it.  If you are a CW operator then you already know the value of a good keyer.  If you are a QRP enthusiast’s, then I’m sure you have added a CW keyer to one of your homebrew transmitters or transceivers.  We all take CW keyers for granite since they are built into our commercial rigs.  However, if you suddenly find yourself in a situation where there is no keyer available and you are faced with using a straight key all day long, you instantly begin looking for options.  This is exactly what happened to me while designing a QRP transmitter.  I realized that there simply was no room on my circuit board for a keyer.

            Since I could not incorporate a CW keyer into the space available it would be necessary to build a stand-along keyer.  I thought that this is not all bad since the keyer could be used with any solid state transmitter and future QRP projects. Almost all of the keyers that I see on the market use a Piezo device or transducer of some sort for audio output.  I wanted to use a small on-board speaker instead of a Piezo device so I decided that the addition of a small audio amp would also be a necessary feature to incorporate into the design. However, for those of you who would rather use a Piezo device, I incorporated pads on the board to accept a Piezo device sold by Jameco.   The circuit board design was a standard boards that I have deisgned to fit into a PACTEL enclosure, model LH43-100.  I use this combination for as much as possible in order to give my projects a consistent look.

            The project began by researching available keyer IC’s.  It soon became obvious that I would not have to do any circuit design since all of the companies  who produce keyer IC’s also provide complete circuit schematic's with their products.  All that would be necessary was to design the printed circuit board to incorporate the keyer circuit and redraw the schematic to include my audio amp..

            I finally decided on using the PK-4 IC from Jackson Harbor Press.  My decision  was based on the number of features incorporated into their device.  I would probably never use most of the features with the possible exception of a small memory for storing a CQ along with my call letters for contest purposes but it sure is nice knowing that everything I could ever need is there.  I didn't have to dig to deep into the research phase before I realized that many of the keyer IC's all used the same pin out.  This provides an interesting possibility for using the keyer as a test-bed for playing around with various keyer circuits since there are so many different keyer chips that are pin-for-pin compatible. 

            I included the schematic drawings for the circuit used but you can also print a copy of the original drawing from the Jackson Harbor Press website at http://home.att.net/~jacksonharbor/ham.htm.  There you will also find several different CW keyer kits that may fill your needs.  I personally do not like projects that have a circuit board with wires running all over the inside of the enclosure. I design my projects so that once all the parts are mounted to the printed circuit board, the project is finished except for mounting the circuit board into an enclosure.  Here is a drawing of the circuit board which shows the parts location on the board.. When I had the board manufactured I did not have solder mask and parts identification silk-screen done on the board since it was to be a first run test board to prove that the circuit works and that the layout is correct.

    This photo shows the complete circuit board mounted inside the bottom half of the enclosure.  Notice that the front and back panels simply slide into grooves at each end of the case.  It is simply a matter of locating and drilling the holes to match the component locations.  This is where I always have trouble getting everything to line up properly but if you take your time and make careful measurements it is possible to get a professional looking finished piece of equipment..  Just remember the old saying, measure twice, drill once!

    If there is enough interest from people wishing to purchase printed circuit boards, I will have them manufactured and offer them for sale at a reasonable price  For those people interested in building the W7JI keyer I have prepared a complete parts list for purchasing the parts used to build the keyer as shown. .  The Parts List is for purchasing all the parts from Mouser Electronics and includes the Mouser Parts Number. 

    The schematic drawing differs slightly from the original drawings from Harbor Pr4ess in as much as I used 0.1uF bypass capacitors instead of the .01uF caps as designated on their drawing.  Also, I have included the audio amp circuit which powers the on-board speaker.

   This project was a lot of fun to produce.  I always feel like I get to build these types of projects twice, once on the computer creating the printed circuit board layout and again, building the actual circuit boards when they arrive from the manufacturer.  This is a very powerful little keyer and has many features which I personally will never use but is good to have them available just in case.  If you decide to build this keyer, I hope you enjoy the project as much as I have.  Good luck with this or any of your projects.  Best 72/73 to all.