Category Homebrew

Arrow antenna

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Introduction The arrow antenna is a popular antenna for using FM transponders on satellites. These satellites have a uplink on the 2m band, and a downlink on 70cm. You can operate those satellites with a simple dualband handheld radio.

TNC-X

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Introduction The Dutch Amateur Radio Emergency Service (DARES) is currently setting up a messaging system for emergency communications. Email is sent over radio using the good old AX.25 protocol. Part of this project is the TNC-X, a simple packet radio…

HEDZ antenna for 80 and 160m

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Introduction The zeppelin antenna (or simply “zepp”) is a popular end-fed wire antenna for shortwave bands and has lots of simularities with the J-pole antenna. It consists of a long wire (half wave length), connected to one of the wires…

40m Vertical

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Introduction During the PACC contest in 2009 we missed a good performing antenna for 40m. So during the preparation for this contest in 2010 I built a dedicated vertical for 40m.

DK7ZB yagi for 144MHz

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Introduction After the somewhat disapointing results of the DJ9BV antenna, I decided to try another model. This time I selected a 9 element DK7ZB for my test. I already bought some square alu bars, each 250cm tall. Since the 9…

CW keyer for foxes and beacons

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Introduction 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…

DJ9BV yagi for 144MHz

Introduction I just started building a new yagi antenna for 144MHz. I used to work with short yagi’s, based on DL6WU, with 6 elements. These antenna’s were about 2m long. I stacked them, tested them both vertically and vertically polarized/stacked,…

6-Element yagi for 144 MHz

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Introduction I designed this antenna in 1995. I wanted a horizontal antenna which has nice characteristics for contest usage. The side lobs are minimized, the beam width is quite large while it has a reasonable gain and front/rear ratio.

HF 1:4 balun

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Introduction Some years ago a friend offered me an HF radio: an Icom IC-730. I decided to buy it, since I didn’t have a HF rig yet. I gave it a nice place on my shelf, connected some meters of…

Your first transmitter

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With just a few components, you can make your own morse code transmitter. The output is only a few miliwatts, but this is enough to receive on any radio in your home. In fact, it is only a simple Clapp…