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For longer runs of control cable, use a line loss calculator to ensure you supply the proper control
levels needed.
Approximate BCD Control Line Lengths.
Minimum Copper
Wire Gage (AWG)
Length
24
1,000 feet
22
1,500 feet
20
2,000 feet
Receive Eight Circle Passive Vertical Elements
The
DXE-RCA8B-SYS-2P
Eight Circle Array is intended to
be used with eight customer supplied
passive vertical elements designed for single band operation. Elements should be installed with
ground radials with their feedpoints as close to the ground as possible but above any standing water.
Your passive vertical elements must be identical and need to be constructed so that they are
resonant on your array band of choice. Their feedpoints must be matched to 75Ω coaxial cable in
order to match the DX Engineering RCA8B-1 system impedance of 75Ω. Short elements are
required to prevent mutual coupling and top loading with symmetrical capacity hat wires is
recommended to add electrical length.
It is important that the ground radial system is identical on each vertical element in the array.
Extensive details on the construction of the required passive elements are contained in
“ON4UN’s
Low Band Dxing”
by John Devoldere, available from DX Engineering.
Array Spacing
Performance of the
Receive Eight Circle Array
can noticeably decrease if structures radiating even
small amounts of noise or signals are within 1-wavelength of the array. There is no detrimental
effect when a higher frequency array of small receiving elements is placed inside the circle of a
lower frequency array of short elements.
Note: The
DXE-RCA8B
Eight Circle Receiving Array System should be separated from
transmitting or other antennas and structures (particularly metal) by at least 1/2-
wavelength. Less separation may cause significant pattern distortion and the
introduction of re-radiated noise into the system. This becomes apparent as reduced
front-to-rear directivity in one or more directions or a higher noise level.
With so many variables involved, there is no optimum or minimum spacing for effects on pattern.
The best practice is to install the array as far as possible from tall conductors or noise sources, or
