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Theory of Operation of the Eight Circle Array
The following Sections contain specific information about the fundamentals of the Eight Circle
Array. It contains all of the information needed to make decisions about the band coverage desired,
and how band coverage is affected by the selection of the optimal pattern in relation to the circle
radius. Also included is information discussing the differences between the use passive or active
vertical elements.
System Design Features and Benefits
The DX Engineering Receive Eight Circle Array System
designed by
W8JI
offers the best
directional receiving performance in proportion to the space required. Advanced design makes the
DX Engineering’s Eight Circle Array, with stable, clean, narrow and low-angle pattern in eight
selectable directions, the ultimate receiving antenna.
The
DX Engineering Receive Eight Circle Array
is the highly sophisticated receive eight circle
system that uses time delay phasing - rather than the conventional narrow-band, frequency
dependent phasing - to provide eight 45 degree spaced directional patterns. The time delay phasing
is directivity-optimized to produce wider and deeper rear nulls and a narrower main lobe. The result
is that noise and undesirable signals are greatly reduced by superior front-to-rear (F/R). The array
forms a clean stable pattern with high directivity over wide bandwidth.
W8JI initially developed and used this array in the 1980’s. This
array started appearing in the 1990’s at larger more advanced low-
band DX stations. The phasing system in this array, as well as the
active
element design, offer much better dynamic range and
directivity bandwidth than other later copies.
Unlike unidirectional transmitting arrays using large elements, very
small elements do not create significant mutual coupling related current-
distribution and phase errors. Better control of phase and currents
provides a much cleaner pattern than found on available vertical antenna
transmit arrays.
Time-delay phasing produces a
frequency independent
rearward null. Additionally, this array
combines independent unidirectional cells across the full width of the array to add additional
broadside directivity. Broadside phasing is also frequency independent.
Phasing remains perfect over very wide frequency ranges. This results in excellent front-to-back
performance on multiple bands, despite using a single delay line with fixed element spacing. The
deep rearward null reduces rearward noise and undesirable signals over very wide frequency ranges.
The rearward null is frequency independent up to element-to-element spacings of just over 1/4-
wavelength.
The DX Engineering
RCA8C-1
Receive Eight Circle Array Controller uses sealed relays sized for
receiving applications. (High current contacts, suitable for transmitting, commonly have unreliable
Summary of Contents for DXE-RCA8C-SYS-4P
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