The Pixie 2 is a tiny rig, with a standard two transistor transmitter. It's a Colpitts oscillator, left running, and a keyed power amplifier. There is no external mixer used to feed the audio amplifier. Instead, the mixing is done at the final amplifier itself with the resulting audio taken off the emitter.
As you look at the audio amplifier you will certainly notice D1. It is an unorthodox approach, but it works. The diode can be left out but it helped to keep down the "crashes" during keying by shutting down the 386 chip. I'm no wizard at this... I just tried it and it seemed to work. I'm sure there's lots of you that have much better ways.
There's no RIT, a simple switch and cap in parallel, between the crystal will work as an offset though. You'll lose QSK but, here again lies the call for enhancement. The whole idea here was to make a tiny rig that worked, with LOTS of room for improvements, using a minimum of parts.
Contacts spanning hundreds of miles are routine with this rig on 80 meters. Band changing is simply a matter of pi-network and crystal changing. If you build one, I'm sure you'll have fun with it. Construction can be by any method, perfboard, "ugly" and pc board. Complete parts kits are available for those of you who are interested.
You will need a low wattage soldering iron with a small tip, some rosin core solder, solder wick (for removing parts when you make mistakes), small wire cutters, needle nose pliars plus any additional tools you may wish to use.
PLEASE PROTECT YOUR EYES WHILE CUTTING LEADS AND SOLDERING COMPONENTS! WARN OTHERS CLOSE BY. THE IRON IS HOT!
Since all the components, except for U1 the LM386, are mounted vertically, it's best to start at one end of the board and work to the other. No particular starting point is necessary. Take your time, enjoy the assembly. Your transceiver will be finished sooner than you think. There are no coils to wind, no alignment either. This is definitely a FUN project.
Note: There is one component that will be mounted on the underside of the board if you build it with the PC board. This is the 1K resistor in the kit. Refer to the drawing on the parts layout for it's location.
Before you get started, note the following parts MUST be installed only one way: the 10uF electrolytic caps, D1 diode, the two transistors, and finally the audio amp chip, U1, a LM386. Make sure you mount these components exacly as the parts layout shows you to. If you mount any of these the wrong way, your transceiver will not work and you may destroy the part. The only exception is C11, but it is best to install it as shown.
Mount all the parts, again, starting from one end of the board. Carefully check to see you have the correct part before installing it in it's location. Refer to the parts layout drawing. Double check before inserting the part. This will avoid problems in getting your rig on the air. Install the 1K resistor last. This resistor is R5, and it is tack soldered between the 9 Volt pad and the POSITIVE terminal of C10. Dress the leads of this resistor so that they don't touch the board. You might want to put some sleeving over the leads, or, some electrical tape underneath to be sure they don't short to the board. R5 is shown in dotted lines on the layout.
This transceiver does not have RIT (receiver offset). It is possible to work other stations, if you are close to their frequency. Even if the received signal is off frequency, give them a call. A simple RIT circuit using a mini-toggle switch and capacitor, hooked up in parallel, and placed in the line between the crystal and ground works well. You won't have full break-in, but it works.
Remember, all that's needed to change bands on this rig is change L3 and the crystal, and you have a rig for another band!! You can use "walkman" style headphone, with a mono adapter. There is even enough audio power to drive a speaker. It's not very loud but you can hear easily in a quiet room... neat!!
This rig has been packaged in a 35mm film can, a Tic-Tac box, Sucrets box (easy), just to name a few. The enclosure is up to you. One just big enough to hold the rig and the 9 Volt battery will give you a tiny self contained unit.
Many contacts using a simple end fed quarter wave wire, worked against a good ground, have been made with this rig. Most of them have been over hundreds of miles away. The transmit signal is very clean, with no key clicks since the oscillator is always running. Just listen to it!! Power output is in the 200 to 300 milliwatt range. You'll be amazed what happens at this power level with a decent antenna.
This is a "bare-bones" rig. User your ingenuity or enlist the help of an experienced ham to help enhance the operation of your rig. Refer to QRP articles, like those in QRPp, SPRAT, ARCI and others devoted to QRP operating. If you're not an experienced builder, this kit was designed especially for you. If you've been building circuits, it's hoped you'll have fun with this little rig and/or help a beginner get started in the wonderful world of QRP.
Parts kits for the Pixie 2 are available from : Kenneke Communications You will need the following additional items (not supplied in the kit, but are also available from the above source): 2-RCA jacks, or 3.5mm jacks for key and antenna 1-3.5 mm mono or stereo jack, depending upon your headphones 1-short piece of RG-174 for antenna connection 1-crystal socket or pair of mini-alligator clips, you may solder in the crystal for the contest. L3 is 1uH for 40M version and Crystal is in the 40M band.