Category: Homebrew

Simple tweak for breadboard power modules

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Example of a breadboard power module

Nowadays breadboards are often sold with a breadboard power module and a bunch of jumper wires included. This power module allows you to easily apply 5 and/or 3.3 volt to the power rails of the breadboard using an external power source. However, often you need a higher voltage in your project as well, maybe 9 or 12V to power your Arduino, relay, audio amp, etc. This little tweak shows you a simple yet effective solution.

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Prepare for a new time!

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Time… For some reason we tend to stick to an ancient system which has no logic at all. Let’s be honest: if we would invent a new time system nowadays, it would probably not have 7 days in a week, 24 hours in a day and 60 minutes per hour. It would be something decimal, like all other units in the metric system. So it’s about time to get rid of this outdated system and switch over to decimal time, by building your own Decimal Time clock!

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Neophyte receiver for 60 meter

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The receiver is ready, except the RX gain potmeter which is still in backorder…

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).

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Receiving SAQ and other VLF stations

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The huge VLF antenna of SAQ near Grimeton, Sweden (credits).

This article is about receiving radio stations operating in the VLF band (3-30 kHz). Due to the very low frequency, receiving such stations requires some special equipment, since most radios don’t support these low frequencies. One of the interesting stations in this band is SAQ, which occasionally transmits at 17.2 kHz. Other stations include submarine communications and time services. — more →

How to get rid of your prototype board

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The ATmega328 microcontroller, just removed from the Arduino board, ready to start living on its own.

When you started discovering microcontrollers, you probably bought some kind of evaluation or prototype board. The microcontroller chip itself is placed in a nice socket on a PCB, surrounded by power circuit, some I/O, and RS232 or USB connector for programming. But after a while you want to remove the chip from the board and place it in your first own application. What do you need to get the chip running? — more →

Step attenuator kit

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The 30dB step attenuator, in a nice case.

I’m the proud owner of a MiniVNA for quite a few years already. One of its features is that you can use it as an RF signal generator. However, the output power cannot be adjusted, so I needed an attenuator. I could build one myself of course, but for about the same amount of money you can buy a kit at the dutch web shop of Kent Electronics. I never tried their kits before, so I decided to give it a try. — more →

Tiny Tornado for 80m

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The closed box.

Many years ago I built a prototype of the famous “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 →

Short DL6WU yagi for 23cm

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My 23cm yagi antenna, in fixed position to the local ATV repeater.

In the previous Winter I built a HB9CV-in-a-box for 23cm for my uplink to the local ATV repeater PI6ATV. Although this antenna works nicely, its gain just isn’t enough when their 23cm preamp is broken (which, unfortunately, is the case most of the time). To achieve a more steady uplink, I decided to build an antenna with a bit more gain, at least 6 dB extra compared to the HB9CV. A short yagi should make this possible. — more →

Getting started with Arduino: morse keyer

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Close-up of the prototype keyer.

Using a paddle to operate in morse code is very convenient. But paddles don’t create dots and dashes on their own, so you need some electronics, called a “keyer”. You may use the build-in keyer of your radio, but most of them lack of functionality. You may buy a keyer at your local ham store, but these are rather expensive. So why not build your own keyer? It’s fun to do, and you learn new things. The Arduino prototyping board allows you to build the most advanced and personalized keyer that you have in mind! This article gives you a decent start for such a keyer, by implementing the basic functionality and learn a bit about the Arduino platform if you’re not familiar with this board yet. — more →

First experiences with my 30m QRP transceiver

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Final shot of the rig, including labels, key and headphones.

This year I built a very nice 30m QRP transceiver, based on a design by Onno PA2OHH. Meanwhile I have used this rig a couple of times, and did some measurements too. This article tells some of my experiences with this great little box. — more →

Simple signal tracer

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The completed original version of the signal tracer.

I found a really simple project for kids to attract them to homebrewing and hamradio. It is also very nice for people who want to learn soldering electronics. It’s a “signal tracer”, which means it detects all kinds of RF signals radiated by devices around you. It demodulates the signal, allowing the user to actually “hear” signals produced by a TV, computer, LED light, electrical wiring in the walls, etc. I showed it to different people, they all went walking around the room for a while and curiously listened to all the different signals. — more →

5/8 Wave vertical antennas for HF

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Our 5/8 vertical for 20m, during a windy day.

Lots of radio amateurs build their own verticals. Most of them tend to stick to vertical antennas with a 1/4 or 1/2 wave sizing. Just a happy few build a 5/8 wave vertical antenna. This is remarkable, since the 5/8 has the lowest angle of radiation and has about 1dB more gain (compared to 1/4 and 1/2 verticals). So the 5/8 should be the favourite choice for DX’ing.

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Adapter for LC meter

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The LC meter adapter in action.

The dutch electronics shop Van Dijken Elektronica sells a nice kit to build your own LC meter. The kit includes a professional PCB, all components, building instructions, prepared case and leads. The kit takes an evening to assemble, the result is an instrument to measure capacitors and inductors. Every radio amateur should have one. — more →

Altoids L-tuner

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My Altoids L Tuner

A while ago Tjeerd PA3GNZ donated me some Barkleys mint tins (identical to the famous Altoids tins), which are rather popular by QRP builders to house small homebrew stuff. Two weeks later I found a czech webshop, offering a kit called “Altoids L-tuner”. This kit perfectly fits in such a tin. Since this tuner would be a perfect add-on for my 30m QRP transceiver, I immediately ordered it. — more →

70cm bicycle antenna

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My bicycle with 70cm J-pole antenna attached to the carrier.

During the summer season I sometimes travel to work by bike. It’s a 21 km trip through the countryside, passing cornfields, orchards, deer and spoonbills. The road includes dikes and bridges, and even a ferry to cross one of the branches of the river Rhine. Especially in the early morning it’s a real pleasure to enjoy all the surrounding nature.

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 →

30m QRP transceiver – Part 4

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Inside view of the radio, including all modules built so far.

Since I finished all modules for the receiver part (power, LF, VFO and RX-board), it was getting time to put everything together and place it in a nice case. Onno PA2OHH (designer of this radio) managed to put the complete transceiver in a single Teko 4B case, so I ordered that same box. Actually I already bought it at the beginning of the project, to help me dimensioning the modules. With such limited space, planning the physical layout of the radio (both the front panel and the inside) is very important. — more →

PC6REC ATV station

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PC6REC ATV station during the REC Fielddays 2014.

During the 2014 edition of the REC Fielddays I facilitated a live videofeed,  broadcasted throughout the Netherlands. Using three cameras and a bunch of (mostly) vintage hardware, the live stream was uplinked to the local ATV repeater PI6ATV. Viewers could witness all activity on the field to get a glimpse of this annual event. — more →

Kenwood interface for visually impaired radio amateurs

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The interface, ready to be mounted to the radio.

This article describes an add-on for modern Kenwood transceivers to allow visually impaired operators to use these radios with a VS-3 or VGS-1 voice synthesizer. I built this interface for Adrian PA0RDA (using a TS-2000), but I’m almost sure that more visual impaired radio amateurs will be interested. The add-on is easy to build, most of the work is mechanical while the electronics are easy. — more →