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Europeans from the eastern USA (northeast direction), try to position the array so the dominant
local noise is southwest of the array. There is no advantage at all when an array points into the
noise, no matter what the array gain is.
Gain does not generally matter, only the ratio of signal response to noise response changes S/N
ratio. The only way S/N ratio improves at HF is if the array nulls the noise more than it nulls the
desired signal.
The second-best location for the array is when the noise source is as far as possible to either side of
the array. If you look at patterns, the ideal receiving location for the array is one that places
undesired noise in a deep null area.
If your location doesn’t have the usual noise sources (power lines, electric fences, etc.), locate the
array so that your other transmitting antennas and buildings are off the back or side of the primary
array direction.
Consider these things about noise sources:
If noise is not evenly distributed, performance will depend on the gain difference between
the desired signal direction (azimuth and elevation) and average gain in the direction of
noise.
If noise predominantly arrives from the direction and angle of desired signals (assuming
polarization of signals and noise are the same) there will be no improvement in the signal-to-
noise ratio.
If the noise originates in the near-field of the antenna, everything becomes unpredictable. This is a
good case for placing separate receiving antennas as far from noise sources (such as power lines) as
possible.
Mounting the Four Square System Phasing Unit
The Four Square System Phasing Unit is mounted on a customer supplied mounting pipe at the
center of the four square array. A galvanized pipe ranging from 1 inch OD to 2 inches OD may be
used. The standard 1-1/2" galvanized water pipe (with its 1.9" OD) is just fine for this application
and can usually be found at your local home building supply store. Included with the Four Square
System Phasing Unit is one
DXE-SSVC-2P
V-Clamp. Copper strap or buss wire used for
connecting the radial fields should also be connected to the center mounting pipe.
Figure 2
shows a
typical connection scheme for the copper buss or straps.
DXE-CS2-100
Copper strap and clamps
are available from DX Engineering.
The length of the Four Square System Phasing Unit's mounting pipe is dependant on your location.
The standard 1-1/2" galvanized water pipe (with its 1.9" OD) is just fine for this application and can
usually be found at your local home building supply store. The Four Square System Phasing Unit
should be high enough to connect the coaxial cables and be above any standing water or snow build
up or backsplash from rain that could enter the case causing electrical problems.