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 holl_ands | Home > Quasi-Parabolic Antennas  
Quasi-Parabolic Antennas
UHF Quasi-Periodic (KISS) with Flat Panels approximating a Parabolic Reflector +  Various Feed Antennas analyzed using 4nec2.
Date(s): 21 Mar 2013. 1 - 3 of 3 Total. Shared
UHF KISS 4-Panels 1x1m + 8-El LPDA Feed
1. UHF KISS 4-Panels 1x1m + 8-El LPDA Feed  (21 Mar 2013)
UHF Quasi-Periodic (KISS) with 4-Panels (1x1-m each) and 8-Element Log Periodic Dipole Array (LPDA)
Feed analyzed using 4nec2.  Distance From Corner to Shortest LPDA Element, x=34.61-inches.

UHF Raw Gain = 17.3 to 19.3 dBi, F/B & F/R Ratio Min = 13 dB and SWR (75-ohms) under 2.4.

Dimensions and 4nec2 file from GHZ24's website:
http://ghz24.freeshell.org/antenna/models/newermodels/parabolas

To simplify the model (and speed up execution times), a simple Horizontal Wire Model was used,
spaced at about 2.8-in (7.1-cm).  Best performance [esp. F/R & F/B] is provided with
1-2 in (2.5 - 5-cm) vertical wire spacing, such as Grid style Animal Cage/Fencing material.
7092 Visits
12 Images
Shared Album
UHF Cube Corner Refl (1x1x1-m) 8-El LPDA
2. UHF Cube Corner Refl (1x1x1-m) 8-El LPDA  (13 Nov 2013)
UHF Cube Corner Reflector (1x1x1 meter) + 8-Element Log Periodic Dipole Array (LPDA)
analyzed using 4nec2.  [Uses three sides of a Cube with a 5x5-cm (2x2-in) Grid.]
Distance between LPDA and Corner of Cube was adjusted for "best" Gain performance.
Unfortunately, tuning for better SWR significantly reduced Gain.

UHF Raw Gain = 13.5 dBi +/- 0.5 dB, F/B & F/R Ratio Min = 11 dB and SWR (75-ohms) under 3.5.

Note that it does NOT maintain the excellent F/B & F/R Ratios and low SWR of 8-El LPDA Alone:
Raw Gain=8.6 dBi (+/- 0.2 dB), F/B & F/R Min=27.2 dB and SWR under 1.4:
http://imageevent.com/holl_ands/zigzaglpa/uhflpda/uhf8elveelpdastubopt
3393 Visits
15 Images
Shared Album
Cube Corners
3. Cube Corners  (15 Nov 2013)
Alternative Cube Corner Designs for your amusement.....
4630 Visits
8 Images
Shared Album