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Examples of Array Performance
The
DXE-RCA8B
eight circle array system occupies less space than phased Beverage arrays and is
much easier to install, is less conspicuous and operates over a wider frequency range with similar or
better performance.
The Eight Circle Array achieves an optimal pattern when the array has a
radius of .327-wavelength.
This is represented by this azimuth pattern in
labeled as “.325-wavelength radius”, which shows the best combination of a
narrow front lobe and acceptable side lobes. This pattern is true for any
frequency from 500 kHz to 30 MHz. This pattern achieves the best
Receiving Directivity Factor (RDF), which is a figure that compares the
forward-lobe gain to the average gain of the antenna array in all directions,
including azimuth and elevation. More information about the rating of
receive antenna systems and Receive Directivity Factor are described in
“
ON4UN’s Low Band Dxing
” by John Devoldere, available from DX
Engineering (DX Engineering part number:
ARR-8560
).
As shown by the patterns of
Figure 9
, an optimized 160 meter Eight Circle Array is not useable on
80 meters. That is why the best performing Receive Eight Circle is built as a mono-band array.
The ultimate low band receiving antenna would be two Eight Circle Arrays, one optimized for 80
meters built inside of the other optimized for 160 meters. Each is optimally sized for a .327-
wavelength radius, according to the dimensions in
Table 4
.
The DX Engineering Eight Circle Array offers better directivity than the Receive Four
Square. However, it requires more real estate to accomplish better directivity, which in turn
requires eight selectable directions to cover all directions properly.
Only a monoband array may be installed with passive verticals or active vertical elements, but a
multi-band Eight Circle Array must be installed with Active Vertical elements.
Multi-Band Arrays with Active Elements
Only the DX Engineering Active Receive Verticals or Active Matching Units with constant 75Ω
impedance and unsurpassed dynamic range across the frequency range will allow this Eight Circle
Array coverage. See the manual for the
DXE-RCA8B-SYS-3P
Eight Circle Array Electronics
Package, or the
DXE-RCA8B-SYS-4P
Complete Eight Circle Array System Package.
Considering the available patterns from the Eight Circle Array, the best possible choice for a two-
band array covering 80 and 160 meters is one that is optimized for 80 meters. The resulting patterns
are represented closely to the patterns in
Figure 9
by the “.325-wavelength radius” for 80 meters
and by the “.15-wavelength radius” for 160 meters, with a narrower pattern and performance
exceeding short Beverage arrays.
