Receive Eight Circle Array
Complete System Package
DXE-R8C-SYS-V3
U.S. Patent No. 7,423,588
DXE-R8C-SV3-INS Revision 0
© DX Engineering 2022
1200 Southeast Ave. - Tallmadge, OH 44278 USA
Phone: (800) 777-0703 ∙ Tech Support and International: (330) 572-3200
E-mail: DXEngineering@DXEngineering.com
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Table of Contents
Introduction
3
Are you ready to build your Receive Eight Circle Array?
3
DXE-R8C-SYS-V3 Complete System Package
4
Additional Parts Required, Not Supplied with the DXE-R8C-SYS-V3
4
Eight Circle Layout
4
System Overview
5
Installation
6
Control and Power Connections
6
Receive Eight Circle Active Vertical Elements
9
Ground System
10
Lightning Protection
10
Array Spacing
11
Station Feedline, Active Element Feedline and Delay Line
11
Vertical Element Feedlines
12
Typical DXE-R8C-SYS-V3 Receive Eight Circle Configuration
13
Delay Line
14
Optimizing the Array
14
15
System Design Features and Benefits
15
Frequency Coverage -vs.- Element Type
16
Receive Antennas - Gain and Efficiency
17
Site Selection
17
Effects on Patterns
18
Site Selection in Relation to Noise Sources
18
Proximity to Transmitting Antennas
19
Examples of Array Performance
20
Multi-Band Arrays with Active Elements
21
Delay Line
23
Topographical Considerations
24
Sizing the Array
25
Receive Eight Circle Troubleshooting
27
Technical Support and Warranty
32
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Introduction
Congratulations on your purchase of the DX Engineering Receive Eight Circle Array System,
which offers the best directional receiving performance in proportion to the space required.
Advanced design, with a stable, clean, narrow low-angle pattern in eight selectable directions,
makes the DX Engineering Eight Circle Array the ultimate receiving antenna.
The Eight Circle Array System is an eight element, eight direction-switchable array based on a
four element end-fire/broadside combination of short receiving vertical elements. This antenna
array is capable of delivering pattern directional performance superior to standard or short Beverage
or reversible Beverage systems, and typical three element or four square arrays of short vertical
elements. The DX Engineering Receive Eight Circle Array System offers selectable directional
performance comparable to eight very long phased Beverages, and does so in far less space.
Advantages of this DX Engineering Receive Eight Circle Antenna System over other arrays:
W8JI design DXE-RCA8C-1 Array Controller with stable, narrow and low-angle pattern
Directional performance varies with circle radius
Includes eight RSEAV-1 Receive Short Element Active
Vertical antennas with stealthy 8.5 foot aluminum elements
System covers a single band or multiple Amateur Bands,
typically 160, 80 and 40 meters; it is functional from 500 kHz
to 30 MHz.
Excellent directivity in a smaller space than phased Beverages
for better signal-to-noise ratio than transmit arrays and other
receive arrays
Reduced susceptibility to high angle signals compared to
phased Beverage antennas, as well as superior performance
over EWE, Flag, Pennant, K9AY antennas.
Switching console selects one of eight 45° spaced directions
Directivity over a very wide frequency range
Less physical space and less maintenance required than phased Beverage antenna arrays
Enhanced relay contact reliability
Low current DC powered control console allows system operation without AC power mains
The DXE-R8C-SYS-V3 is a complete Receive Eight Circle Antenna Array Package that can be
installed as a Mono-Band or Multi-Band system for 160 through 40 meters using a recommended or
alternative array radius for the frequency coverage desired. A single delay line can be made to
accommodate the desired band or bands of operation according to the information provided in the
Delay Line section of this manual.
Are you ready to build your Receive Eight Circle Array?
We are pleased that you have purchased a Complete Receive Eight Circle Array System Package
model DXE-R8C-SYS-V3 because you wanted the ultimate receive antenna system complete with
Active Vertical Antenna including mounting hardware and rolls of coaxial cable with connectors
and tools; virtually everything required to install a complete system. Before you proceed with
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installation, there are some fundamental concepts that you should know.
1. Have you sized your array to achieve the desired performance within your space? Do you
know where you will be locating your Receive Eight Circle Array? Review the explanation
of the optimal monoband and multi-band frequency coverage of the Eight Circle Array in
sections entitled Array Performance, Site Selection and Sizing the Array.
2. Are you ready to build your system? Proceed!
The DXE-R8C-SYS-V3 Receive Eight Circle Array Packages includes:
DXE-RCA8C-1 Receive Eight Circle Array Controller
DXE-CC-8A Special eight position Receive Eight Circle Control Console modified to
provide +12 Vdc for powering the active antennas.
DXE-SSVC-2P Stainless Steel V-Clamp for mounting the RCA8C-1 Receive Eight Circle
Array Controller to a mounting post between 1" and 2" OD
Eight DXE-RSEAV-1 Active Verticals with AVA-3 Active Matching Units, Aluminum
Vertical Elements, Insulated Mounting System and Stainless Steel V-Clamps to be used
with customer supplied ground rods for ground mounting
DXE-RG6UFQ-1000 (Two) 1000 Foot Rolls, Quad Shield Coaxial Cable, 75Ω, RG6
Flooded Cable
DXE-CPT-659 Coaxial Cable Prep Tool for RG6, 75Ω Coaxial Cable, w/extra blade
DXE-SNS-CT1 F-Connector Compression Tool for 75Ω coaxial cable connectors
DXE-EX6XL-25 Package of 25 F Connectors for quad shield 75Ω RG6 coaxial cable
Additional Parts Required, Not Supplied with the DXE-R8C-SYS-V3
One additional DXE-RG6UFQ-1000 75Ω quad shield Coaxial Cable that may be required
for the main feedline from the station to the array
Five-Conductor Power and Control Cable. The modified DXE-CC-8A Control Console
interfaces to the DXE-RCA8C-1 Eight Circle Array Controller through a 5-wire cable to
select one of eight directions and to power the eight active elements. Economically priced
DXE-CW9S is a 9-conductor control wire which may be used allowing the user to use the
spare wires to double up on power and return lines for current carrying capability.
Eight Ground Rods 6 ft. length x 5/8 in. diameter min., used as supports and crucial
grounding for the eight DXE-RSEAV-1 Receive Short Element Active Verticals.
Eight Circle Layout
The optimized array for single band performance has vertical elements
arranged in a circle with a radius of about 175 feet for 160 meters, or 84
feet for 80 meters, or 44 feet for 40 meters. A two-band array for 80 and
160 meters should also have a radius of about 84 feet. See the Theory of
Operation sections for exact dimensions, options for wider frequency
coverage and guidance in choosing the best orientation.
The default direction of the array with no voltage (BCD 000) places
elements 1 and 6 in front and elements 2 and 5 at the rear, with pairs of
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lines through two opposite vertical element pairs (tangents) that point to the receiving direction.
Elements 1, 2 and 5, 6 are selected as the default for a forward direction of North-East for North
America, with elements installed as shown. A mirror image of this element positioning would
achieve a typical default North-West for European installations.
Figure 1 - Typical Diagram of the DXE-R8C-SYS-V3 Receive Eight Circle Array System
System Overview
The DXE-R8C-SYS-V3 system is comprised of the modified DXE-CC-8A Eight Position Control
Console, the DXE-RCA8C-1 Receive Eight Circle Array Controller, eight DXE-RSEAV-1
Receive Short Element Active Vertical Antennas and one Delay Cable with F-Connectors installed.
These units interconnect and work together using factory default settings to control the Receive
Eight Circle Array. The modified CC-8A control console uses BCD switching voltages for the
RCA8C-1 to change the receiving direction of the array and supply power to the Active Verticals.
When the modified CC-8A Eight Circle Control Console and the RCA8C-1 Receive Eight Circle
Array Controller are connected as shown in the installation section below and the layout is as
described for North America in Figure 1, the switch positions on the modified CC-8A will switch
the array in the eight directions as shown in Figure 2.
Figure 2
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Installation
The RCA8C-1 Receive Eight Circle Array Controller can be mounted to a customer supplied
galvanized steel pipe driven into the ground at the center of the array. A galvanized pipe ranging
from 1 to 2 inch OD may be used. The length of the controller unit's mounting pipe is dependent on
your location. The standard 1-1/2" galvanized water pipe (with its approximate 1.9" OD) is just fine
for this application and can usually be found at your local home building supply store.
The RCA8C-1 relay unit has been pre-drilled to accommodate up to a 2 inch OD pipe using the
included DXE-SSVC-2P Stainless Steel V-Bolt Saddle Clamp for 1" to 2" OD pipe. An optional
DXE-CAVS-1P V-Bolt Saddle clamp can be used for pipe from 3/4" to 1-3/4" inches OD. The
controller can also be mounted on a sturdy wooden post if provision for grounding the RCA8C-1
unit has been made. Note: JTL-12555 Jet-Lube SS-30 Anti-Seize should be used on all clamps,
bolts and stainless steel threaded hardware to prevent galling and to ensure proper tightening.
The Receive Eight Circle Array Controller unit should be mounted as shown in Figure 3 with cover
upward and the control and coaxial cable connections downward to prevent water from entering the
box. The stainless steel base of the Receive Eight Circle Array Controller unit has weep holes to
allow condensation that may build up inside the unit to leave.
Figure 3 - RCA8C-1 unit mounted to 2" OD pipe using the included DXE-SSVC-2P V-Clamp
Control and Power Connections
1. Locate the removable green connector on the rear of the modified CC-8A labeled "G A B C D”.
The green connector is a two part connector as shown and the top part can be removed by
pulling it straight off. This will allow easier wire replacement or servicing as needed. When
pushing the removable connector back in place, ensure you press straight inward to fully seat
the connection.
2. Insert the five wire cable on the green connector as shown in Figure 4.
3. The same five wires are connected to the RCA8C-1 removable green connector (G A B C D) as
shown in Figure 5. (“D” is required only for voltage on the element feedlines and should not be
connected for passive vertical arrays.)
4. The modified CC-8A Control Console requires a nominal +12 Vdc fused input (+12 to +14
Vdc, 2 Amps and well filtered) through the 2.1 mm connector on the rear of the unit.
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A 2.1 mm power cord is supplied with unit. The wire with the white stripes is the +12 Vdc.
Outer Connection is GROUND Center Pin is +12 VDC.
Figure 4 - Connections between the RCA8C-1 and the modified CC-8A
The RCA8C-1 uses a removable five terminal plug as shown in Figure 5. The RCA8C-1
connections are labeled “G A B C D”. The terminals use the same connection letters and are
connected G to G, A to A, B to B, C to C and D to D.
On the RCA8C-1 the green connector is a two part connector as shown in Figure 5 and the top part
can be removed by pulling it straight off. This will allow easier wire replacement or servicing as
needed. When pushing the removable connector back in place, ensure you press straight inward to
fully seat the connection.
Figure 5 - RCA8C-1 Green Connector
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Switch Position
G A B C D
1
GND
0 0 0
1
2
GND
1
0
0
1
3
GND
0 1 0
1
4
GND
1
1 0 1
5
GND
0
0
1
1
6
GND
1 0 1
1
7
GND
0
1 1 1
8
GND
1 1 1
1
Table 1 - Modified CC-8A Output Truth Table (1 = +12VDC)
Control lines (usually BCD ) can normally use good quality CAT5e cable (4 twisted pairs of 24
AWG wire) for runs up to 1000 feet. Typical DX Engineering BCD control lines requirements are
+12 VDC at 25 milliamps.
Depending on the number of control lines needed (usually 3 or 4) you can double up the twisted
pairs of CAT5e cable, or use control wire that is at least 22 AWG, allowing runs up to 1500 feet. If
you use a cable with more conductors, it is a good idea to tie the unused conductors to ground.
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
Active antenna circuitry needs a good voltage supply to operate properly. When supplying power to
an active antenna, you want to have +12 VDC, 60 milliamps at each active (under load).
CAT5e cable is not recommended when making long runs to power an active antenna since the line
loss in CAT5e cable may not supply the proper operational voltages required for active antennas.
Depending on the required length of your power wire, you will want to use a line loss calculator
(voltage drop with various wire gages) to ensure your power supply (normally +13.8 well filtered
DC) will supply a minimum of +12 VDC, 40 milliamps at each active antenna (under load).
A DX Engineering 4 Square or 8 Circle will require approximately 200 milliamps (only 4 actives
are powered at any one time).
When calculating line length, take into consideration the total number of active antennas being
powered at any one time in your line length calculations.
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Approximate Active Antenna Power Line Lengths (4 active antennas on at any one time).
Minimum Copper
Wire Gage (AWG)
Length
18
300 Feet
16
500 feet
12
1,200 feet
10
2,000 feet
Receive Eight Circle Active Vertical Elements
The DXE-R8C-SYS-V3 Eight Circle Array is supplied with one DX Engineering model DXERSEAV-8 which consists of eight identical DXE-RSEAV-1 Receive Short Element Active Vertical
antennas. Featuring the updated DXE-AVA-3 Active Matching Units, the RSEAV antenna offer
excellent broadband receiving performance from 100 kHz to 30 MHz. In addition, the RSEAV
provides a clean, low profile installation using aluminum antenna elements. DX Engineering’s
unique design makes it vastly superior to other amplified and traditional active antennas in both
strong signal handling and feedline decoupling. You get significantly better weak signal reception
due to lower spurious signal interference and reduced noise.
The DXE-AVA-3 Active Matching Units ground the antenna element when power is turned off.
The active antennas allow installations with spacing from transmit antennas less than 1/2
wavelength but more than 1/10 wavelength (on the lowest frequency). Close spacing of the array to
transmitting antennas can be done, but will impact overall receive array system performance. Sites
without sufficient land area for proper spacing should use these verticals, which may be installed in
close proximity to transmitting antennas (1/10-wavelength of the lowest transmitting frequency).
This is possible, provided the active units are powered off at least 5 ms before transmitting. An
optional sequencer such as the DXE-TVSU-1B should be used to ensure the correct transmit to
receive switching
Your eight identical DXE-RSEAV-1 Receive Short Element Active Vertical Antennas are selfsupporting and insulated from the ground rod that is typically used as the ground mount. The
vertical element is connected only to the positive terminal of the DXE-AVA-3 Active Matching
Units, and the negative terminal must be connected to at least the mounting ground rod. Two
ground rods may be needed in some soils. The Active Receive Verticals normally do not need
ground radials, however, depending upon the conductivity of the soil, in sandy soil or rocky soil
installations, wire radials may be required.
The Active Receive Verticals should be installed with their feed points as close to the ground as
possible but above any standing water. The level of snow cover over the feedpoint and the active
vertical is not an issue. If you are planning to use the array on the 160 meter band, the Active
Antenna internal gain jumper can be reset as discussed shown in the DXE-AVA-3 manual. If the
array still lacks sensitivity on the lower bands, then a preamplifier with high dynamic range can be
used to compensate for the low signal level. However, using a preamplifier when sufficient signal is
already present may result in amplification of the noise along with the signal. It is always best to use
the least gain possible.
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Ground System
The four DXE-RSEAV-1 Active Elements work well with just a single 6’ x 5/8” copper ground rod
used as the ground mount. A separate mounting pipe can be used with optional clamps as the
element ground if the pipe provides an adequate ground. Depending on soil conductivity, best
performance may require two ground rods spaced a few feet apart. Increasing ground rod depth
beyond 5 ft. rarely improves RF grounding because skin effect in the soil prevents current from
flowing deep in the soil. Avoid ground rods less than 5/8 in. OD. A good ground system improves
the array performance and enhances lightning survivability. It is very important that each ground
system be the same for each active antenna in the array.
You can test ground quality by listening to a steady local signal. Attach 15 ft. of wire laid in a
straight line (away from the coaxial feedline) to the ground rod. If you observe a change in signal or
noise level, you need to improve the ground. A second rod spaced a few feet away from the first one
may correct the problem or 10 to 12 ground radials, each 15 ft. long, should provide a sufficient
ground system for most soil conditions.
Lightning Protection
While amateur radio installations rarely suffer damage from lightning, the best protection is to
disconnect electrical devices during storms. The key to lightning survival is to properly ground
feedlines and equipment and to maintain the integrity of shield connections. A proper installation
improves lightning protection and enhances weak signal receiving performance.
Consult lightning protection and station grounding information in the ARRL handbooks, or by
referring to the NEC (National Electric Code). The DX Engineering website also has technical and
product information “Lightning Protection and Grounding”. Use lightning surge protectors for the
coax feedline and control lines such as the DXE-RLP-75FF Lightning Protector, Receive 75Ω, DC
Pass, with F Connectors, for the array feedline at the station end single point ground.
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