Technical Support and Warranty Figures Figure 1 - Site Selection Clear Distance Figure 2 - Layout of the DXE-RFS-SYS-4P Four Square System Figure 3 - Active Element L1MF Jumper Locations Figure 4 - Array Diagonal Dimension Figure 5 - Jumper Locations showing Default Settings...
Low current DC powered control console allows system operation without AC power mains DXE-RFS-SYS-4P (U.S. Patent No. 7,423,588) is a complete Receive Four Square Array Package which includes: (1) DXE-ARAV3-4P Package of four Active Receive Vertical Antennas w/ Internal Antenna Disconnect Relays ...
System Overview The DXE-RFS-SYS-4P is an advanced four square receiving system that uses four symmetrically spaced elements to provide switching for a 4-direction receiving antenna system. This unique system uses time delay phasing rather than the single band phase shifting used in traditional four squares.
4-direction selectivity and you still would be limited to one or two bands. The DXE-RFS-SYS-4P system occupies less space, is much easier to install, is less conspicuous and operates over a wider frequency range with similar or better performance.
Page 6
Increasing the array size increases its sensitivity on the lower frequencies, sliding the performance curve toward the low frequencies and potentially eliminating the need for amplification.
Site Selection Site selection is important. The DXE-RFS-SYS-4P system can be positioned as close as 1/10 wavelength to transmitting antennas. The DXE-ARAV3 Active Elements are bypassed to ground when power is turned off. A programmable sequencer, such as the DXE-TVSU-1B is required, and included with the DXE-RFS-SYS-4P, for close spacing requirements.
60 ft Table 1 - Array Safety Distance Minimums at 1500 watts For any DX Engineering Receive Four Square, using the DXE-TVSU-1B Time Variable Sequencer Unit to sequence Active antenna power will ensure that transmitted energy will not cause damage to the receive system.
Noise that limits the ability to hear a weak signal on the lower bands is generally a mixture of local ground wave and ionosphere propagated noise sources. Some installations suffer from a dominant noise source located close to the antennas. Noise level differences between urban and rural locations can be more than 30 dB during the daytime on 160 meters.
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 listed under “Lightning Protection and Grounding.” Use lightning surge protectors for the coaxial cable feedline and control lines.
System Operational Overview The DXE-RFS-SYS-4P system is comprised of the DXE-EC-4 BCD Control Console and the DXE-RFS-2 Control Unit. These units interconnect and work together using factory default settings. The DXE-EC-4 BCD Control Console supplies the nominal +12 Vdc operational voltage as well as the +12 Vdc BCD control voltage.
Station Feedline, Active Antenna Feedline and Delay Lines The weakest link in an antenna system, such as the DXE-RFS-SYS-4P, is often the coaxial cable connections. All connections must be high quality and weather tight to prevent contamination and corrosion, which can cause the feedline impedance to change.
If the resistance of the shield increases due to contamination, the active elements may not function properly. Any splices in the feedline should be high quality and entirely weather tight. Do not use splices in the delay line cables. The DXE-RFS-SYS-4P system has been designed to use only 75 Ω coaxial cable.
Page 15
VF. The included DX Engineering DXE-F6-1000 75 Ω coaxial cable has a nominal VF of 0.85. For best performance, the coaxial cable for the delay lines should be from the same batch or spool.
75 Ω systems. Control and Power Connections If you have the DXE-RFS-SYS-4P system, with the DXE-EC-4 Control Console, no other equipment is needed for powering the DXE-RFS-SYS-4P, the active elements or controlling the receive direction of the DXE-RFS-SYS-4P.
Page 17
Diagram 1 - Default Configuration. 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.
(voltage drop with various wire gages) to ensure your power supply (normally +13.6 well filtered DC) will supply a minimum of +12 VDC, 60 milliamps at each active antenna (under load). A DX Engineering 4 Square or 8 Circle will require approximately 250 milliamps (only 4 actives are powered at any one time).
The switch positions on the DXE-EC-4 control the directivity of the received signal in the DXE-RFS- SYS-4P. As shown in the diagram to the right, position one favors the NE direction, position 2 favors the SE direction, position 3 favors the SW direction and position 4 favors the NW direction when the array is positioned as shown.
Optimizing the Array To determine if the antenna system output level is the limiting factor, tune the receiver to the lowest band at the quietest operating time. This is usually when propagation is poor but some signals are heard. Disconnect the antenna and set the receiver to the narrowest selectivity you expect to use. Receiver noise power is directly proportional to receiver bandwidth (going from 2.5 kHz selectivity to 250 Hz selectivity reduces noise by 10 dB).
DX operations. Receive Four Square Troubleshooting There are several possible causes for a malfunction of a DX Engineering Receive Four Square System. Testing the system is not difficult and can be completed in an hour or so. Separate circuits for directional switching, Active Vertical Antenna power, and antenna phasing can each be affected by a variety of cabling, connection and or component problems.
Page 23
Start 80% of all Receive Four Square malfunctions are caused by Check Internal A, B or C Jumpers Animals, Chewed, Green Connector may have Punctured, Stretched broken a wire or is tightened Broken/Shorted or Broken. against insulation - not bare wire. Conductors Check all F connector center conductor...
Page 24
C) Shorted or opened conductors caused by water migration into a control line or a feedline. Over 80% of all Receive Four Square malfunctions have been caused by the above system problems. A thorough inspection and subsequent testing of each control cable, RF cable, and their respective connections, will uncover the cause of most RFS troubles.
Page 25
4) If the EC-4 has only a couple LEDs lit with the control cable disconnected, then it may have sustained lightning pulse damage and will need to be repaired or replaced. A new DXE-EC-4 is available from DX Engineering. Continue troubleshooting the array control with a good EC-4 or by using a 1A fused power source.
Page 26
RFS unit may require service or replacement. At this point, the problem in your system should have been identified. If you need additional assistance from DX Engineering, feel free to call or write. Detailed discussions of system function, connections, and troubleshooting is best handled by telephone,...
Appendix A Alternate Configurations An alternate configuration which uses the feedline coaxial cable for either the operational power or the directional control voltages, but not simultaneously, can be used. This configuration requires internal jumper changes in the DXE-RFS-2, along with additional hardware to couple the proper voltage to the feedline.
Differential voltages (+/–12 Vdc & 12 Vac) using terminal C. This can be done using a 1 or 2 conductor cable. Economically priced COM-CW-4 is a 4 conductor control wire which may See Table 5 for the control matrix. The optional DXE-FVC-1 can be used to be used.
Diagram 2 - Alternate Configuration All Element feedlines, delay lines and station feedlines must be 75 Ω coaxial cable. RFS-2 internal jumper changes are required. Element feedlines can be any length, but must be equal. Power lines not shown for clarity.
Diagram 3 - Alternate Configuration Using a manual switch connected to the optional DXE-FVC-1 for directional control All Element feedlines, delay lines and station feedlines must be 75 Ω coaxial cable. Requires RFS-2 internal jumper changes. Element feedlines can be any length, but must be equal. Power lines not shown for clarity.
DXE-RFS-2 and Active Element Power The DXE-RFS-2 phasing unit uses and distributes the voltage to power the active antenna elements. For all four active elements, a nominal +12-15 Vdc at 250 mA current is required. The default configuration uses Terminal C on the 5-position plug for power. The DXE-EC-4 is used to power and control the DXE-RFS-2.
Default Jumper Configuration Settings Figure 5 shows the default jumper settings for the DXE-RFS-2. For JMP1 & JMP2 the center and top pins of both are shorted. For JMP3 & JMP4, the center and bottom pins of both are shorted. Figure 5 - Jumper Locations showing Default Settings JMP1 Selects Power Voltage Source: Coax or J12 - Shown in default position, voltage from J12 JMP2 Selects Direction Voltage Source: Coax or J12 - Shown in default position, voltage from J12...
If you wish to reduce feedline radiation and improve reception, a Feedline Current Choke is recommended if your SWR is already low. Adding a DX Engineering Feedline Current Choke at the point where the feedline exits the area of the antenna will substantially reduce unwanted feedline radiation or reception without the need for improved station grounding.
Page 34
Control is done using a standard 1 of 4, BCD or switch closure interface. The FVC-1 is recommended for use with the DX Engineering RFS-2P Remote Four-Square Antenna System , the RBS-1 Reversible Beverage Antenna System , and the RLS-2 Transfer Switch . The CC-8A Control Console can provide the 1 of 4 and BCD input used by the FVC-1 or you can use your own switch.
Page 35
The DXE-PSW-12D1A is an AC Wall Transformer Adapter to furnish 12 Volts DC at 1000 mA from 120 Vac 60 Hz input, fused output. It features a standard 2.1 mm plug connection for 12 Vdc. Outer connection is GROUND Center Pin is input for +12 VDC. Ideal separate power source for DX Engineering EC-4 BCD Switch...
Warranty All products manufactured by DX Engineering are warranted to be free from defects in material and workmanship for a period of one (1) year from date of shipment. DX Engineering’s sole obligation under these warranties shall be to issue credit, repair or replace any item or part thereof which is proved to be other than as warranted;...
Need help?
Do you have a question about the DXE-RFS-SYS-4P and is the answer not in the manual?
Questions and answers