Some years ago I provided some workshops on local radioclubs, demonstrating the capabilities of Arduino boards. Along with the workshop I handed out a quick reference card to get started. Recently I was asked to do another workshop, so it was time to update my QRC. I thought it’s worth sharing, so here it is. — more →
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).
I thought it would be nice to chat with some local radio amateurs on my way back home. I often talk to Adrian PA0RDA while driving home (by car) after work, using the local 70cm repeater PI2ZST, so I decided to prepare my bike for this UHF band. — 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 →
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