UHF 21El Curtain Array - NO Refl (20 Oct 2014)|
|UHF 21-Element Curtain Array (NO Reflector) analyzed using 4nec2 after RESCALING Wi-Fi version|
posted by Ross Anderson, W1HBQ. Also corrected AGT=1.0 after fixing SOURCE Wire Statement error.
Rescale ended up with AWG5 Wire Size, but as small as AWG10 can be used with 75-ohm NARROWBAND
mode, and with 150-ohm BROADBAND mode, upgrade to 1/4-in Copper Tubing is recommended.
Hi-VHF Curtain Quad Array (5 August 2009)|
|Hi-VHF Curtain Quad (CQ) Antenna Array (w/o Reflector) analyzed using 4nec2.|
A Curtain Quad Antenna Array consists of 7 or more Half-Wavelength radiating Elements (Horizontal for TV),
interconnected by (Vertical) feedlines, forming as many Rectangular Boxes as you have room for.
Includes 7-Element (CQ7) and 9-Element (CQ9) Arrays starting with the Classic CQ Rectangular shape.
These are NOT the only usable dimensions. The overall size of the array can be Rescaled somewhat, varying
the Height/Width Ratio (HW) to bring the Max Gain peak back to mid-Band. A (shorter, wider) CQ7 alignment
was found, but the overall Gain was reduced by 2 dB. These alignments fix the box width at 30-inches, no Rescaling.
Snipping out the outermost Vertical parts of the CQ Rectangles actually improved Gain on all frequencies.
The Center, Driven Element was shortened to improve SWR, at the expense of lower Max Gain (mid-Band).
For CQ9, the Outer Horizontal Elements were also brought inward (like an Accordion) to improve Lo/Hi-Freq Gain,
which also decreased the overall width of this (HUGE) array.
Information re CQ can be found here:
Above are Horizontally Polarized. Fol. is Vertically Polarized, showing narrower Center Element to improve SWR: