Building the tetraQuad
I don't know the real name for this antenna, but it is four Quads
stacked end on end and feed in alternating phases. It also seems to be an extremely forgiving design. I
made quite a mess of the construction and I'm getting somewhere close to 14dBi gain. It is very close
in performance to the lucent 14dBi antenna I have (theoretical max 19Dbi). I did think I was getting none, but discovered that the antenna is horizontally polarized when held vertically. It seems to have quite a wide horizontal pattern, but a limited vertical one. This is wider than the theory suggests and is no doubt where the extra gain went.
I also built a six diamond version, but it performed no better (or worse).
- I used 3.2mm (1/8") Mang-Bronze welding rods. These are really hard to bend and
the diamonds are quite small so made several smaller sections and soldered them together.
- I put a bit of tape around the cross over point where the outer diamonds meet the inner ones.
- I used a small piece of 2mm copper wire to bridge the gap.
- The N-Socket is bolted to the back plate (cut from an old copper water tank) with nylon screws.
- The antenna is held off of the back plate (1/8 wavelength) by 2mm diameter copper wire (the original plan had coax).
|From the front.|
|From the Back|
|Looking down on it when it is aligned for vertical polarization (i.e. the diamonds are horizontal)|