The Final Touches

 At last, my paraset is complete, albeit with a few hiccups. First, I couldn't get the switching configuration quite correct. It seemed that every time I tried soldering in the crystals, the switch would begin to melt. Too hot I guess! Other than that, my paraset kit works excellent. Now all that's left is a field test...

So what am I left with since the switching configuration didn't work like I had hoped? There's still the option of putting in a crystal socket, which would make switching out crystals easier. You only need a SIP socket like this. Cut it to where you only have 3 pins, like this.

The only drawback is that you would have to remove the faceplate every time you want to switch frequencies. The pro is that you can use both crystals and resonators as frequency references.

Another option is to bite the bullet and make the switching unit. Unfortunately I don't have very much time when it comes to free time, so until I better my soldering skills, I think that this option is nothing but impossible. Maybe later on down the road it will be possible, but until then I'll have to wait and see.

I have seen many posts and projects that would allow the Pixie to change bands. All that needs replaced are C3, C5, L2, and C6. C3 is in the oscillator circuit, and C5, L2, and C6 are part of the LPF circuitry. There are many crystals that come in frequencies which are close to both CW and Feld Hell portions of the bands, such as 10.140 (10.143 is the Feld Hell frequency), 14.060 (14.063 is Feld Hell), and many more. As stated in the last post, using a variable capacitor between 100 and 300 pF will bend the crystal by 2 - 3 kHz, but results may vary by crystal size. It will also bend a resonator roughly 100 kHz. Adding an inductor within the circuit may also increase frequency range. A value like 5.6uH will suffice.

Whatever I decide, I am overall very happy with the outcome. I can't wait to start learning CW and send some Feld Hell. I think that it will be possible to make more of these easily, but I might have to settle with space constraints. In this project, I used a 4 x 6 metal recipe card box, but 3 x 5 boxes are more commonly available, especially in metal. This project has taught me a lot about craftsmanship, how to get creative, and use what you have available to you. In total, I think this project cost less than $20, well below my budget constraint. Even if you can't get the switching circuit to work correctly, you can still enjoy the Pixie by adding some frequency agility.

As the snow begins to thaw and it starts to get warm out, I have a few locations that I'd like to try my paraset kit at, mainly at the university that I attend. There are so many spaces that will definitely fit a 40m simple wire dipole that are almost or completely unobstructed.

Here are some troubleshooting tips that I have after this building experience:

• No sound - Check the battery voltage, check soldering joints
• Buzzer/sidetone constantly on or faint - Check that the variable capacitor is not touching the faceplate or anything metal. Check the oscillator stage.
• RIT is intermittent or not working - Check solder joints

The list is small, but these were the common problems that I ran into. Of course, these aren't all of the possible problems. The most important thing in any troubleshooting is to go back and retrace your steps. Are your soldering joints good? Are there any loose connections? Are components in the right spot, or have they gone bad? 

I am not an expert and I have no professional testing equipment like an oscilloscope. If you are still having problems, talk to someone who knows how to help or even ask your Elmer, if you have one.

Although this has been a simple modification, the sky is the limit when it comes to the Pixie. For instance, here are some ideas I'd like to try:

• Try replacing the transistors with power transistors to get more power output
• Make the Pixie into an AM transmitter, or better yet, an AM transceiver
• Make a propagation beacon or QRSS beacon
• Add some filtering circuitry to filter and narrow the audio to about 700 Hz
• Try experimenting with different antennas

There is so much more to this list that you can do with a Pixie. Because it is QRP, calling CQ may take a while. If your wrist gets tired, try sending Feld Hell. One advantage of Feld Hell is that it uses less of your transmitter's or transceiver's duty cycle. There is also a multitude of free software that allows Feld Hell operation, such as fldigi. If you have a Raspberry Pi, which can run off of a portable charger, you can take your ops to the field easily. 

Now that I think about it, because I have already drilled a hole for the switch, I could use that hole to put in a power switch. As I mentioned before, when I get better at soldering, I plan on doing the crystal switch. For now, I just want to fill the extra space, so I think a power switch is a great idea. 

To wrap things up, I think that this project has shown me just how simple a transceiver can be. With simple modifications, a rock-bound QRP radio can be as frequency agile as a commercial transceiver, while still being field serviceable. Truly, this project has been a success out of a small failure.

Until next time...