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.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |