Data Hacking

Chapter 4 — Antenna Hacks
Aluminum and stainless steel are tricky to solder. If you want a material that is easy to
solder, then select copper.
2. Build the helix base: Cut a 40.6-centimeter (16-inch) length of any nonmetallic material
tube to form the base of the helix (see Figure 4-16). Plastic tubing is ideal for this
because you can expose it to the elements without it degrading. If you want, you can
also add an end cap to the base to keep out water and inhibit corrosion. If you are going
to do this, then remember to add 25 millimeters (1 inch) to the length of this tube.
Make sure you cut the ends of the pipe square and flat so it will lie perpendicular to
the ground plate when it is mounted. Smooth it off with some sandpaper to make sure
that it is true.
FIGURE 4-16: Building the helix base
3. Create the helix coil: The best way to wrap the wire around the base is to first clamp a
ruler to the helix coil base (the pipe) and use that to draw a line from one end to the
other, parallel to the center line of the tube that you are using. Along this line, measure
intervals of 2.3 centimeters ( 7 ⁄8 inch) from one end (this will become the base of the tube
that you will later attach to the ground plate), and place a mark for the beginning of the
first turn of the helix winding. From this first mark, and along the line you drew, measure
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