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clanon
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Everything posted by clanon
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Easily 12 dbi at 725 mhz
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Could be made to ANY frequency , Circular pol (could be made lineal easy) efficiency could be better NOT using FR...
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4:1 balun (50 ohms to 200 ohms , 75 ohm to 300 ohms , etc)
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Correct adaptation from 50 ohms to 300 ohms antenna (Quarter wave long should take velocity factor of Coax in length ) 0.66 PET , etc
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a Ratio between antenna Impedance and radio impedance the bigger the difference bigger the losses...let's sat 300 ohm antena/ 75 ohm radio 4:1 VSWR = close to 40% reflected power on TX...on RX it's gonna be WORSE...(small signal)
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0.2 0.3 BRASS paper...? and a sharp cutter...several tries (using a printed PAPER taped on top) cut through the printed lines...? solder the vertical strips... PS: 0.2 is pretty RIGID...
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Yagis hit a WALL at 15 dbi most of the times (with 15 elements and a BIG reflector)...you need 2 for 18 dbi , 4 for 21 , etc
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nope...BUT those complex feed networks steal gain (several db)
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double post
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Water absorption should be adressed in PES foam...Changes ALL. PVC pipe has THIS weirdness...
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LOOP should be CLOSED at feeding Points... then , EACH Loop should be feed with 90 degrees phase difference
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Double lineal here , NOT circular "The polarization of the emitted signal depends on the spatial location of the antenna. Horizontal - horizontal, vertical - vertical polarization. [4] The horizontal position represents when both squares are next to each other, the vertical position is when both squares are placed one above the other." DoubleBiquadOmni-Antennafor2.4GHzWirelessLinkApplication.pdf
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YES you treat it like a simple dipole (but polarization is 180 degrees inverted for a double quad) Then to get Circular Polarization , you need to retard 90 degrees the wave at each quarter making a 0 90 180 270 rotation (for this the easiest approach is a Quarter wave length (dielectric in coax included) from One biquad to the other...
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it should be possible with a 90 degrees (velocity factor of coax x 1/4 wavelength) between both antennas (but interactions should be simulated)...
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one of the LOWEST in the world 0.0003 at 3000 mhz , only one better Polypropylene...at higher frequencies...5.8 ghz ideal...
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I would give it a go ...BUT with circular patches...we'll see...(you had one like that YEARS ago... mimo...remember...
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yup...5.84 cm by 5.4 cm...(these are HIGHLY related to the Dielectric Factor , change from 0,4 to 0,5 would change several millimeters these dimensions)
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it would be interesting...could be Laser cut or stamped...Wires have more REACTIVITY (Imaginary Z) Inductive reactance...impedance curve is always smaller...2mm copper ...maybe... Copper tape is easy to cut with cutter under print drawing taped on top...perfect you get more losses in the metal distances should stay the same and sizes... to keep a good Impedance and low 2 mm or LESS from reflector the Feed network Patches 4 mm or more from reflector (there is a step of 2 mm)
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Styrofoam (lowest density better) cut with resistance wire (nichrome) at 2 mm flat
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i have A model (my ssd failed with the original but i had the dimensions on paper) could put the dxf of the feed and patches are ALL the same 42 by 44 cm reflector Model should be customized to Dielectric used in each case branches.dxf Centerfeedline.dxf patches.dxf
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Feed network is at 2 mm from Aluminum Reflector , Patches are at 4 mm from Reflector... There's a "tendency" these days to believe that Laser cutting-3D printing and AESTHETICS are a key factor...FALLACY Energy doesn't care about aesthetics it only Flows were possible , mm or single degrees error don' make much of a difference BUT dielectric Constant MUST BE KNOWN...to get to the ballpark.