NightFire Electronics

A few days ago, I thought that I'd make another purchase off of AliExpress again. I went to the store and picked up a prepaid Visa card since that's what I used last time, only to discover that it was only valid in the US. Dang. Well there went $50...

Along Came Etsy

Now I know what you're thinking...why would you ever shop on Etsy, Owen? What do they have on there that's even remotely close to ham radio? 

Well they have a lot actually. Hams are making things from antennas, LED signs, kits, apparel...the list goes on! What a great way to let the ham community shop for items while giving back to their fellow hams and their families! I might start making antennas and selling them on Etsy, actually.

Since I couldn't buy a Pixie kit on AliExpress due to my dilemma, I decided to go find another Pixie kit. I couldn't use eBay because they don't accept prepaid cards and Amazon just wouldn't recognize my card period. So I got to looking at other sites and Etsy came to mind. Sure enough, one supplier - NightFire Electronics - was one of the first seller choices. And right there it was - a 40 meter Pixie kit waiting for me to put it together. So I ordered that along with an audio Morse Code practice oscillator as another building activity.

The Waiting Game and Thoughts

I placed my order on October 26th and according to USPS, my package should arrive on October 29th - that's a pretty quick turnaround considering that NightFire Electronics is in Florida, which is continuing to clean up after Helene and Milton.

Despite this, my package arrived in a cute cube of a box. Nothing too grand, but sometimes the best things in life come in small packages. I went ahead and unboxed my pack of goodies and sure enough, the two kits I had ordered were provided as promised and promoted. 

The Pixie

To my surprise, the Pixie isn't that much bigger than the generic ones you get off of eBay. The PCB is a bit thicker and seems a bit more robust too. 

This one still uses varactor tuning but I have learned a lot about varactor tuning in the past few days. Basically, when a diode is placed backwards (cathode side towards the voltage source, anode to ground or negative source) it exhibits a phenomenon known as junction capacitance. As the voltage is increased or decreased, the capacitance varies. There are specific diodes that serve as varactors such as the MV209 used in the MFJ Cub, but common 1N400x series will work just fine if used as fine tuning, such as RIT. The Pixies use these diodes for varactor RIT tuning, which provides a small variable capacitance and receive offset of between 700 and 900Hz - perfect for copying CW! If you really wanted to, you could substitute an actual varactor in place of this to have a wider tuning window. You'd just have to adjust for offset every time you keyed up.

I purchased the Pixie kit with a base frequency of 7.030MHz. Now, I could keep buying up crystals and swapping them out to change frequencies, or I could use a variable capacitor to shift the frequency by about a kilohertz or so. Your mileage may vary, especially if you're using an HC49/U (tall-cased, more pull) versus an HC49/S (short-cased, small pull). Also, don't permanently solder in the crystal. You can use pin headers to easily change out crystals or VXO modules.

The Pixie did not come with any output jacks. Rather it was provided with four 2-pin screw terminal. This shouldn't be a problem and the input/output jacks should be relatively easy to come by. I already have tons of BNC panel mounts, a panel mount DC barrel jack, and several 3.5mm jacks.

This Pixie has an additional capacitor in parallel with the low pass filter inductor. You can add a value of 130pF to further attenuate spurious emissions, although the schematic says that this component isn't used. I find it to be absolutely necessary, as I have been thoroughly analyzing the ineffective output of the Pixie's filter. This capacitor helps significantly reduce the second harmonic to a dip, which thereby reduces the third, fourth, etc. by more than -25dB or so from the fundamental. It works because it is resonant on or near the second harmonic, which is 14MHz.

Code Practice Oscillator

While I liked my Arduino Nano CPO, it just wasn't small enough to tote around. I ended up purchasing another oscillator kit based on a twin-T oscillator configuration. This is fed into an LM386 to amplify the output, which is a sine wave at around 700Hz.

Depending upon the kit you have, you can change a resistor in one of the T-networks to change the tone. So if you're not comfortable with 700Hz you can experiment with resistor values to see what you like. As an added bonus, I'm thinking of adding on an Arduino to the key input to generate random words and phrases. A digital pin fed to an optocoupler and fed into the keying input should do the trick just fine.

Conclusions

Simply put, I will most definitely be buying more things from NightFire. I feel that they are reasonably priced and are dedicated to making electronic kits accessible for all. One kit that looks cool and is easy to assemble is their ghost detector. Whether or not it works...well, that's for you to decide. In practicality, it is an overly-amplified LED detector that picks up electromagnetic changes nearby. 

That's not the only things NightFire offers. They offer everything from amplifiers, Arduino kits, capacitor/resistor kits, and so much more! So if you're looking for some fun kits to build either to pass the time or practice your soldering skills, look no further than NightFire Electronics!