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yurik82

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About yurik82

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  1. upper fundamental limit is 13.7/17.1 dBi for 470/700 MHz to get any gain from dish - one need dish feeder (illuminator). Feeder itself typically have gain in range 9...14 dBi (optimal directivity depsnds on f/D of parabolic dish) If you have feeder with 10...14 dBi gain, why would you add extra parabolic dish to get the same 10...14 dBi (at 50% illumination efficiecny, which is very good efficiency, hard to achieve)? Bad news is that you can't achieve 50% illimination efficiency at UHF. For offset parabolic dish 30% I consider very good result, and for center-fed dish 20% is very good, due to shadowing.
  2. https://youtu.be/nCIDvrs5UzI?t=105
  3. if you are going to dramatically change feed port design - you need to optimize port capacitance. -j 20 ... -j 60 is too much capacitance (remove or decrease improvised capacitor) Request for this antenna was direct TV cable mount (via F-screw soldered to reflector) P.S. do 75 Ohm SMA exist?
  4. jX curve is heaviliy dependent on port design - diameter and length of feed pin wire + size of lip-capacitor at port Jomy has SWR=1.41 @ 2.13 GHz, my model has SWR50=1.44 @ 2.13 GHz
  5. the same design principles apply to hexagonal patches. I find ellipses convenient, so I calculated dimensions only for ellipse. Pseudo-ellipses work pretty much the same, one need to calculate exact dimensions
  6. I simplified this design - more compact reflector (14x22 cm flat reflector is viable minimum) and single copper wire. For 2x2 ellipse design - same approach. only copper wire and no additional L/4 stripline transformer