BiQuad Antenna 70cm / 422MHz

thingiverse

Be aware I making the prototype now (9jan2021). I might need to do some fine tuning. This is a easy way to build a biquad antenna for UHF frequency. Components needed are a piece of metal sheet for the reflector i will be using a 5mm aluminum 710mm x 355mm. Wire for the radiator, I planning to use RG223, And use the screen as a ordinary wire, a piece of 15mm, (1/2inch) celflex in the center to connect to the radio, this are the tricky part. I will upload some photos when it's done. You need to print 13 standoff with cap's. I am using PETG from prusa. A normal twin biquad (4 square's) give 14-15dBi. For experimenting I made "stand_extender" for making one(or more) extra layer of biquad (director as in yagi antenna) hopefully adding 3dBi => 18-19dBi ;) For a dual biquad you need: 1x stand_off_C.stl --- center piece where the coax are connected 2x stand_off_X.stl --- One in each cross 10x stand_off_V.stl --- All "corners" for improved weather proofing 3x Cap_X.stl 10x Cap_Y.stl For a second layer you need 3x stand_extender_X.stl 10x stand_extender_V.stl And you need some 4mm nuts ans bolts to connect the standoff's to the reflector. You might need to modify some thing. So I am adding the source file for OPENSCAD. Feel free to play around. I used https://www.changpuak.ch/electronics/bi_quad_antenna_designer.php for calculate my measurements of the antenna.