Building the Cylinder (Can) Waveguide

Frequency	b/g Chnl 1 b/g Chnl 2 b/g Chnl 3 b/g Chnl 4 b/g Chnl 5 b/g Chnl 6 b/g Chnl 7 b/g Chnl 8 b/g Chnl 9 b/g Chnl 10 b/g Chnl 11 b/g Chnl 12 b/g Chnl 13 b/g Chnl 14 -NZ Indoor- a Chnl 34 a Chnl 36 a Chnl 38 a Chnl 40 a Chnl 42 (mid-range) a Chnl 44 a Chnl 46 a Chnl 48 -NZ outdoor low- a Chnl 50 a Chnl 52 a Chnl 56 a Chnl 57 (mid-range) a Chnl 58 a Chnl 60 a Chnl 64 -NZ Outdoor High- a Chnl 149 a Chnl 152 a Chnl 153 a Chnl 157 (mid-range) a Chnl 160 a Chnl 161 a Chnl 165	GHz
Diameter		mm (Inside Measurement)
Free Space Wavelength		mm
Waveguide Wavelength		mm
Max Frequency		GHz
Min Frequency		GHz
Cut Off Frequency		GHz
Probe Length		mm
Open End to Probe		mm (Open End to probe center)
Probe to Reflector		mm (Probe center to Reflector)
Inside Length		mm (Reflector to Opening)

The final product only needs to be accurate to about 1mm as this will only shift the frequency within the range of the 802.11 spectrum. A smaller cavity length will shift the frequency response to that slot to a higher channel. A longer slot cavity length will shift it down.

Methods and madness

Misc Notes

• The probe is a 2mm diameter copper wire soldered into an N-Socket and cut to 31mm (1/4 free space wavelength, including the protruding bit of the N-Socket).
• The N-Socket is held down with nylon screws. If you use metal screws, use stainless steal ones and keep them short so they don't protrude into the cavity.
• Water in the antenna, or spider and insects will be a problem. One suggestion is to seal around the edges of the reflector with silicone and cover the open end with a piece of plastic (microwave friendly and thin).

N-Socket with 1/4 wavelength copper wire (including the length of the bit of the N-Socket it is soldered into). This becomes the probe for the antenna.