Warm the pipe and the plate for about a minute to get the correct temperature. Just drill a hole that's as deep as the required front distance, 17 mm, and place the copperplate onto the pipe as shown. This method made it much easier to position the pipe and soldering it to the copper plate. I created a stand to hold the pipe out of a wooden brick. Use protective goggles whenever using soldering equipment. I haven't used a electic solder iron but I bet it's not powerfull enough, instead I used a mini-gas soldering tool with a open flame. Getting the correct front distance and temperature is tricky. Soldering the pipe to the copperplate is the hardest part. It's also wise to roughen the point where the copper plate is supposed be attached so that the solder can more easily bind to the copper. Use some sandpaper to get it smooth and correct the dimensions. If you got a fairly long pipe, fasten it to a bench and use a saw to cut into the pipe 3 mm from the end and then remove the notch by cutting into the center of the pipe. The old, or first, SWR distance chart suggested 30.5 mm (1/4 wavelength), this was later ruled as wrong (see above).Ĭut off the notch before cutting the length of the short pipe. This should be optimal since the entire element is in the sweet spot between 15-17 mm. The most efficient element distance is 15-17 mm. By attaching the element's wire centre at 16 mm, will the lower part of the wire be just above 15 mm and the top be just under 17 mm. This table shows the element distance from the reflector and the SWR measured on channel 7 on a DWL-900AP: Distance SWR is the amount of energy absorbed and radiated by an antenna compared to the amount it reflects back to the transmitter. It's measured in relations to 1, a perfect impedance is 1:1. It's important that the SWR (Standing Wave Ratio) is as low as possible so that the antenna is as efficient as possible. The recommended length is 50 mm but could be anything above 18 mm (front distance + copper thickness). The pipe is used to attach the element and coax cable later on. Use a 12 mm drill piece, make sure it's fastened in the exact center to avoid vibrations. Measure from each corner to the opposite to find the center. To limit the sidelobes (leakage of signal from the backplate) to the back of the Biquad, attach or bend two 'lips' on both sides of the reflector along the axis of the element to concentrate the radiation forward, as shown in the picture. Tupaware or weatherproof enclosure ReflectorĬut the copper plate in 123.10 x 184.66 mm dimensions. The calculations for the dimensions: Width = Full wavelength = 123.10 mm.123,10 x 184,66 mm copper plate (PCB, aluminium or some other metal works).I've read several reports that people are using Biquads thats off-specifications and still works great, so I presume the design is relatively insensitive to smaller inaccuracies (but I recommend you follow them). The Biquad below is based on instructions by MartyBugs (which is based on Trevor Marshall design). Tests shows that has a gain of around 11-12 dBi, and double Biquad can put out around 13-14 dBi. It's one of the few good antennas you can use as a feed for dishes, along with Cantenna.

BiQuad Antenna Biquad AntennaYou can use the the Biquad antenna either in combination with a parabolic dish or stand-alone.

Triple biquad wifi antenna