Good Day, Pleasant Reader.
In the following I attempt to describe a single band
antenna. The Sterba Curtain.
I found the details for the Sterba curtain in two books:
Kraus "Antennas", and the 1974 "ARRL Antenna Book".
Together, both books give a clear picture.
Here's my summary:
Two arrays CAN be built, one 1/4 wave behind is the reflector
and about 5% larger. For Bi-Directional communication just
build one. Two feed point locations are mentioned: 600 ohm
and 1000 ohm. the 600 ohm is at a lower corner, the 1000 Ohm
feedpoint is at the bottom/center between two of the
1/2 wave sections.
1/4 1/2 1/2 1/2 1/4 <-----Section widths
__ ____ ____ ____ __
| | | | | | | | | | ^
| X X X X | |
| | | | | | | | | | (1/2 Wave Tall)
|__| |____| |____| |____| |__| |
(A) (B)
Feed at A or B with Open-Wire Line.
Z(feedline) A=600 Ohms.
Z (Feedline)B=1000 Ohms. Maximum or less than 1000 Ohms.
Notes:
"X" is transposed open wires.
The Currents into the top and Bottom sections are IN-PHASE.
The Vertical sections are Anti-phase and cancelled.
Therefore, this configuration is Horizontally Polarized.
Height of array should be 1/2 wavelength above ground
for the bottom horizontal elements. Since the vertical phasing
lines are 1/2 wavelength, the top will be 1 wavelength up.
When using feed point A, you open the wires there. AT
B, you close A. B is already open, just connect there.
You may use as many 1/2 wavelenth center sections as you
like, but always have 1/4 wave end sections.
Wish I had the room!
By the way, you can also run this vertically or use
fewer 1/2 wave sections. Radiation is Broadside.
-Ed Loranger, we6w
--
72/73 de we6w qrp es cw ONLY (From non-ham to extra in one day!)
HW-8;OHR-100, Pixie2, Johnson Viking II w/VFO.
QRP-L#1068/Norcal#2227/ARS#275/ARCI#9397 grid CM88ok
mailto:we6w@qsl.net http://www.qsl.net/we6w