Biquad antenna of UHF band (430...446 MHz)

thingiverse

I am pleased to offer my holiday project - biquad antenna. Its features are: - high-gain (9.2 dBi); - wide-band (16 MHz SWR<1.5, 38MHz SWR<2.0); - rather thin for such gain (15cm, 8cm between elements). The biquad covers a vast portion of HAM radio 70 centimeter band (SWR about 1.1) and it works on PMR band (446MHz) quite well (SWR about 1.5). Other bands can be rendered, but the pipes' diameters should be preserved. Owing to the fact that the biquad is wide-band, it usually doesn't require tuning and works quite well immediately after manufacturing. It possesses at least 50W power rating. It is supposed to be exposed to outdoor conditions for exteneded periods of time (please examine your filament's manuals closely, PLA is *NO* option, PETG is OK). The project resembles the classical construction represented on the pages of [1], where low-band ~50MHz biquad had been described. The complete bill of materials usually doesn't exceed 5$ and includes: 1. PETG filament d1.75mm - 150g 2. Alluminium pipe 1/4" - 2,1m (copper also suitable) 3. Plastic pipe d20mm - 500mm 4. Coax cable 50Ohm - 1.5m 5. Console pipe d25mm (length is defined by your project) 6. Screw M4x20mm - 12 pcs. 7. Screw M4x10mm (to secure reflector pipes) - 8 pcs. 8. Screw M6x15mm (to secure console holder, if needed) - 2 pcs. 9. Nuts M4 - 8 pcs. The biquad consists of driven element (two quads with side of 165 mm), and 4x reflector elements placed 80mm back of driven element. The length of each reflector element is 350mm. The 3D printed parts included in the project are: 1. Driven element's console (r2bdy-uhf-biquad-console.3mf) - 1 pcs. 2. Hat of the console (r2bdy-uhf-biquad-hat.3mf) - 1 pcs. 3. Reflector pipes' holders (r2bdy-uhf-biquad-refholders.3mf) - 4 pcs. 4. Main holder (r2bdy-uhf-biquad-holder.3mf) - 1 pcs., if required. The coax cable goes through vertical 20mm pipe and next inside the driven element's hole. Then it should be soldered or reliably screwed to driven element's pipes. I'm keen on devising antennas for HF/VHF/UHF, so please feel free to ask questions about this matter. I wonder if you post your experience with it. 73! de R2BDY https://www.qrz.com/db/R2BDY References: 1. The Radio magazine, march 1961, p.47