Elmer 001 - The Pixie 2 Project

"Parts List and Additional Parts Needed" 
By Brice D. Hornback, KA8MAV
Date: Wednesday, January 16, 2002 9:19 PM

Time to get started. Once you receive your kit make sure to verify the parts in the kit. There are also some additional parts needed to complete the kit discussed later in this email.

Pixie 2 Parts List
-----------------
Qty. / Description
(2) 100pF capacitor (NP0 or C0G)
(1) 82pF capacitor
(1) .047uF capacitor
(2) 820pF capacitor (NP0 or C0G)
(1) .1uF capacitor
(3) 10uF miniature electrolytic capacitor
(1) 1N914 or 1N4148 diode
(1) 22uH molded inductor
(1) 150uH molded inductor
(1) 2.2uH (80m) or 1.2uH (40m) molded inductor
(1) 47K ohm resistor
(1) 1.5K (1K5) omn resistor
(1) 33K ohm resistor
(1) 10K ohm resistor
(1) 1K ohm resistor
(2) 2N2222 (or equivalent) NPN transistors
(1) LM386-1 Audio Amplifier 8-pin DIP IC

Additional parts required for building the Pixie 2 kit

• XTAL
  (Fundamental Frequency Crystal on just about any band. The parts are included with the kit for 80 or 40 meters - however, the values of the output filter are wrong for 40 meters (although it still works...kind of) so if you're going to build it for 40 meters... find yourself a T37-6 toroid core (yellow) and use that instead of the molded inductor. More on this later...) This kit says it will work on 160 meters through 10 meters... but 10 meters does require a few different parts. This course will focus on the 40 meter version (7.040 MHz).

• Two 1/8" phone jacks
  (I prefer using a mono phone jack for the key and a stereo phone jack for
  the headphones.)

• Battery Connector
  (9-volt battery clip or 2.1mm jack or ???)

• Antenna Connector 
  (I prefer using a chassis mount BNC connector. If you use a RCA jack, make sure it does not have a black center insulator. Radio Shack carries Red and White ones and these work fine. The black "may" contain carbon and although they will still work... could lead to additional problems.)

• Hookup Wire 
  (Shielded cable such as RG-174 coax works great for connecting things inside the enclosure. (Note: thin shielded cable can be salvaged from a old computer microphone cable or mouse cable.) Or, you can use just about anything else as well. It'll all work but the hookup wire is one area that can cause problems later on with broadcast interference. Keep all the wires as short as possible and if you use standard hookup wire, you can twist the ground wires around the signal/+ wires to minimize interference. Ferrite beads on the wire at the connectors (all except the antenna!) can also help reduce or minimize interference.)

• Metal Enclosure 
  (Yes, an Altoids^(tm) mint tin or any other mint tin works great. However, they are a bit difficult to work with as the metal is very thin and bends/distorts/tears, etc. while drilling holes. A wood block inserted inside the container prior to drilling will really make your life easier.  Always make the holes a bit small and use a metal file to shape the opening to fit your connector. Any other metal enclosure can be used. Radio Shack sells a couple, DigiKey and Mouser carry a LOT of different enclosures, or simply build your own by soldering PCB material together. I like this method as it's easy to get just the right size.)

Additional Parts for Improvements / Mods / More Fun

• Output Filter
  (For best results with this transceiver, find a T37-6 toroid core (yellow) and the capacitors to match the band you'll be putting the transceiver on.  Look at the Tiny-Tornado schematic on the QRPp-I.com Web site for the correct values for the output filter. This is still a very simple output filter that uses very few parts.

• Variable Capacitor
  (A simple VXO can be built using a variable capacitor. Almost any value will work. Small variable caps such as a 20-90pF can be found at DigiKey and Mouser. Larger caps such as those from old radios work fine too.)

• Switches
  (It's nice to have a couple of SPST switches to use as a power switch and a TX/RX switch to switch in a capacitor to change the frequency. Of course, a DPDT switch has more flexibility and can come in handy. Using a 4PDT switch... you can actually build a dual-band transceiver.)

• Sockets
  (A standard Radio Shack 8-pin socket will work fine for the LM386. If you want to experiment a lot with your rig... use machine pin sockets on the XTAL and the PA transistor as well. You could also use machine pin sockets on the output filter to allow swapping filters if you change bands. As mentioned before, the Radio Shack type sockets do not work well for things other than the 8-pin DIP.

• Header Pins
  (Header Pins can be used for connecting the hookup wire to the board. I use male header pins on the board and create a wiring harness using female header sockets. These sockets (with wire) can be salvaged from old computer cases - these are used to connect the switches and LED's to the computer motherboard.)

• Battery (not really optional)
  (Just about any battery will work from 8-volts to 13.8-volts. The more voltage you use, the higher the RF output is. However, the higher voltage causes the PA transistor to get hot so you might want to get a TO-92 heatsink for the PA. I prefer using rechargeable batteries. I've used ten (10) NiMH rechargeable AAA batteries with a lot of success in the Tiny-Tornado. I also charge them from a small solar panel. Also, a nice 12V@5Ah sealed lead-acid battery can be bought at Radio Shack and it's a very nice battery. Make sure you have a way to charge your battery or battery pack. We'll discuss this later as well if necessary.)

• Antenna
  (Build or buy a GOOD antenna. This transceiver works best when used with an antenna tuner as well.)

• Headphones
  (Standard 8-ohm headphones are recommended. A speaker will work but unless you are in a VERY quiet room and the band is wide open... it'll be difficult to hear. The audio output from this rig isn't the best so a good set of headphones is recommended. Headphones such as the ones that come with the Sony Walkman^(tm) type players/radios/etc. work just fine.

• Key
  (This transceiver is meant to be used with a straight key. I highly recommend the Lionel J-38 (personal favorite) but any key will work. Yes, simply touching two wires together works too... but isn't recommended for long QSOs. A momentary push-button switch will also work for emergencies or testing. Electronic keyers will also work but there are some issues using these that will be discussed later. I have a TiCK keyer I use with my Iambic paddles but like I said... there can be some issues and maybe we can work through them together.)

• Frequency Counter / Display
  (Although not required if you keep with the standard XTAL controlled oscillator as it is... it's REALLY nice to know what frequency you're on if you "rubber" the XTAL around it's frequency a bit. I use a DFD3 Digital LCD Display as well as a Az ScQRPion Stinger Singer. I highly recommend both of these and links to these can be found on the QRPp-I.com links page.

Schematic

If you're building the kit Manhattan Style, the Pixie 2 schematic can be found here:
http://www.qsl.net/we6w/projects/pixie2.gif 

Questions so far? We're going to wait a week or so to let people receive the kits and gather parts before we start building.

73/72/71! de Brice KA8MAV
ka8mav@arrl.net 

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Additional Pixie 2 information can be found within the pages of the "Pixie Information Project".

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