The Neophyte receiver is an easy-to-build receiver, already built by lots of people. Many radio clubs used it as a project for starting builders. It was developed by John WA3RNC and first published in QST, February 1988. The circuit can be used to create either a 80m or a 40m receiver, depending on a few capacitors. The 60m band is just in between, therefore I decided to find out the correct caps for this new amateur radio band (well… at least new in the Netherlands, from December 2015).
“Pixie 2”, one of the simplest and smallest CW transceivers ever designed. The main issue is that the TX and RX frequency is the same, so the opposite station needs to shift which he probably doesn’t know, so it takes quite some patience to get a successful QSO. Once published, lots of improved designs appeared in magazines and on the internet, one of them being the “Tiny Tornado”. Since I had some mint tins left, I decided to build this little wonder. — more →Many years ago I built a prototype of the famous
After browsing the web for designs, I stumbled on the website of Onno PA2OHH. Besides lots of other interesting QRP projects, I found his NiceRig 40-30 QRP Transceiver. I immediately fell in love with this design and decided to build this thing.
Building this rig takes quite some time, so I publish this project in different posts, showing you the progress of this project. — more →
“Spijker” is a dutch word for nail, which you would normally use to hang something on the wall, or to construct wooden stuff. However, (brass) nails can also be used as as solder pad. PA0KLS used this idea to construct a receiver, called the “Spijkerradio” (nail radio). It is a nice project for starters to build their own radio.
The receiver is based on the good old 0V1. This was a very simple receiver with only one tube. PA0KLS redesigned the schema to replace the tube by transistors. He also added a small audio amplifier to allow usage of modern (low impedance) headphones or a small speaker. — more →
The Arduino board is a fantastic tool for rapid prototyping, and can help radio amateurs in lots of homebrew projects. I wanted to demonstrate that it is very easy to build an automatic antenna tuner with the Arduino. I connected an old SWR meter to one of my Arduino boards. Furthermore I build a simple L-tuner with a fixed coil and a rotating capacitor (400pF). The capacitor is driven by a servo, also connected to the Arduino. By doing a full sweep with the capacitor, the Arduino tries to find the position with the lowest SWR. After the sweep it turns the capacitor to that position. You can view the video below to see the tuner in action. Mind the SWR meter (right needle) in the back while the capacitor is rotating. — more →
Beacons and foxes have to identify themselves. Although I could sit along all day with my morse key, transmitting my call, I wanted to have some automatic keyer. Since I recently bought a PIC development kit (Velleman K8048), I thought that it would be a nice idea to create my first PIC application by building a CW keyer.
I never wrote PIC source code yet, but I have done some assembly for 68000 and x86 in the past. So it shouldn’t be to difficult to write a simple program, keying one of the outputs of a PIC. On the CD of my PIC development kit I found some sample programs, including one for a flashing LED (this appears to be the “Hello, World!” application for microcontrollers). I modified the source code and finally build the bunch of code which you can find on the bottom of this page. I’m sure that this code is not the best PIC program of the world, but it works and at least I understand how it actually works. If you have any suggestions, please feel free to send them to me! — more →
Fox hunting is one of the many aspects of ham radio. It’s some kind of game, where the “fox” is a little transmitter, and competitors have to locate it using a directional antenna and receiver. I already built a special receiver for fox hunting, and my wife (PD2W) built one too. So having 2 receivers it would be a nice idea to add a fox to these, to get a complete mini-fox-hunt-kit. One of the members at the club pointed me at the so-called “OXO transmitter”. I looked it up at the internet, and immediately liked its simplicity. So I started to build it.
The smallest QRP transceiver for 80 meters, called “Pixie 2”, is a very nice project to start building your own equipment. Minimum components, maximum fun. The spec’s are poor, but what else might you expect for just a few dollars?
In fact, it is only a simple Clapp Oscillator with the output directly driven into a few meters of wire. The transmitting frequency depends on the used crystal. This may be any crystal between 1 and 15 MHz, higher frequencies may perhaps work also, therefore you may lower the 2 capacitors a little bit.
The transmitting frequency is not only the one shown on the crystal, but also “harmonics”: If you have for example a crystal of 3.56 MHz, then it transmits (of course) on 3.56 MHz, but also a bit at 7.12 MHz (2 * 3.56), 10.68 MHz (3 * 3.56), 14.24 MHz (4 * 3.56), etc.
The operating voltage is not critical, a 9 volt battery will do the job.
- C1 – 100 picofarad
- C2 – 100 picofarad
- R1 – 10 kilo-ohm
- R2 – 1 kilo-ohm
- S1 – Morse key or switch
- T1 – BC547 or any other universal NPN transistor
- X1 – Any crystal you like between 1-15 MHz