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DX Engineering DXE-RFS-2P Manual

Receive four square system
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Receive Four Square System
DXE-RFS-2P
DXE-RFS-TS3P
DXE-RFS-TS3P-INS Revision 1
U.S. Patent No. 7,423,588
DXE-RFS-TS3P Components Shown
© DX Engineering 2010
P.O. Box 1491 · Akron, OH 44309-1491
Phone: (800) 777-0703 · Tech Support and International: (330) 572-3200
Fax: (330) 572-3279 · E-mail: DXEngineering@DXEngineering.com

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Summary of Contents for DX Engineering DXE-RFS-2P

  • Page 1 Receive Four Square System DXE-RFS-2P DXE-RFS-TS3P DXE-RFS-TS3P-INS Revision 1 U.S. Patent No. 7,423,588 DXE-RFS-TS3P Components Shown © DX Engineering 2010 P.O. Box 1491 · Akron, OH 44309-1491 Phone: (800) 777-0703 · Tech Support and International: (330) 572-3200 Fax: (330) 572-3279 · E-mail: DXEngineering@DXEngineering.com...

  • Page 2: Table Of Contents

    Table of Contents Introduction DXE-RFS-2P Receive Four Square Array Controller and Switch Package DXE-RFS-TS3P Complete Receive Four Square Array Package System Overview Features Prerequisite Additional Parts Required, Not Supplied Example of Array Performance Site Selection Proximity to Transmitting Antennas Topographical Considerations...

  • Page 3: Introduction

    There are two packaged systems available: DXE-RFS-2P - Receive Four Square Array Controller & Control Box The DXE-RFS-2P is a sophisticated receiving system that uses time delay phasing rather than the conventional narrow-band, frequency dependent phasing systems. The time delay phasing is directivity-optimized to produce wider and deeper rear nulls and a narrower main lobe.

  • Page 4: Dxe-Rfs-Ts3P Complete Receive Four Square Array Package

    DXE-RFS-TS3P - Complete Receive Four Square Array Package for Normal Spacing to Transmit Antennas Complete Receive Four Square Array package for Close Spacing to Transmit Antenna W8JI design • Operates from 100 kHz to 30 MHz • Excellent directivity in a small space for better signal-to noise ratio •...

  • Page 5: System Overview

    System Overview The DXE-RFS-2P 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. When...

  • Page 6: Prerequisite

    Prerequisite This manual covers both the DXE-RFS-2P stand-alone unit and the DXE-RFS-TS3P system. This manual will describe the DXE-RFS-TS3P total system package in detail. The DXE-RFS-3P includes the RFS-2 Receive Four Square Switching Unit and the DXE-CC-8A Control Console. The DXE-RFS-2 includes just the Receive Four Square Switching Unit. The stand-alone RFS-2 unit must be connected with the appropriate power and switching voltages as defined in the Control &...

  • Page 7: Example Of Array Performance

    A test array, constructed at DX Engineering using the DXE-ARAV3 Active Elements and a side length of 35 feet, showed excellent performance across a wide frequency range. This side length is optimal for 40m, according to Table 2.
  • Page 8 In a different test array with 50 ft side lengths, optimum performance occurred between 3 and 4 MHz. Performance on 7 MHz was also excellent. Amplification was used below 2 MHz. The highest usable frequency was 10 MHz. This array also produced usable F/R ratios down to the lower end of the AM broadcast band (600 kHz).

  • Page 9: Site Selection

    Site Selection Site selection is important. The DXE-RFS-TS3P system can be positioned as close as 1/10 wavelength to transmitting antennas. The DXE-ARAV3-4P Active Elements are bypassed to ground when power is turned off. A programmable sequencer, such as the DXE-TVSU-1A, is required for close spacing requirements.

  • Page 10: Topographical Considerations

    For example, transmitting legal-limit power output (1500 watts) into an ideal four square transmitting antenna produces about 6,000 watts ERP (6 dB gain). Because of the increased radiated power level, nearly 1/2 wavelength minimum spacing between the transmitting and receiving antenna arrays is required.

  • Page 11: Ground System

    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...

  • Page 12: Sizing The Array

    Sizing the Array When using active elements, the array side length can be as small as 1/10 wavelength and up to about 1/2 wavelength on the highest frequency to be used. Sizes below 1/10 wavelength result in unusable array sensitivity in the most desired bands. Making side lengths larger than 1/2 wavelength on the highest frequency will split the main lobe and cause pattern and front-to-back degradation.

  • Page 13: Four Square Layout

    Four Square Layout The array antenna elements should be arranged in a square, use Table 2 for guidance in choosing the best combination of frequency coverage and side length dimensions. • The diagonal corners of the square should point in the most desirable receiving directions. Element 1 is the default forward element, Element 3 is the rear or null element.

  • Page 14: Installation

    OD pipe. The controller can also be mounted on a sturdy wooden post, but provision for grounding the DXE-RFS-2 unit must be made. The DXE-RFS-2 is designed to be used with the DX Engineering Active Vertical Antennas or it can be used with passive elements. The user manual included with the active elements has instructions for assembly and installation.

  • Page 15: Station Feedline, Active Antenna Feedline And Delay Lines

    Flooded cable also prevents shield contamination and can be direct-buried. DX Engineering offers an inexpensive preparation tool, part number DXE-CPT-659, that readies the coax for connectors in one operation and comes with an extra cutting cartridge. To ensure weather tight connections, use DXE-SNS6-25 Snap-N-Seal compression style connectors.

  • Page 16: Active Antenna Feedlines

    If you do not know the VF of the coax you are using, you must directly measure the electrical length of the coax you have or obtain cable with a known VF. The DX Engineering DXE-F6-1000 75 Ω coax has a nominal VF of 0.85. For best performance, the coax for the delay lines should be from the same batch or spool.
  • Page 17 For Example: An array with 90 foot side spacing, the diagonal length is 127.3 feet. The 0.95 factored physical length for DLY3 electrical length is 120.9 ft. Multiply 120.9 ft. by 0.85 (the VF of DX Engineering 75 Ω coax). The correct physical length for DLY3 is 102.77 feet, or 102 feet 9 inches.

  • Page 18: Control And Power Connections

    It is important to use 75 Ω feedline to the operating position from the DXE-RFS-2. Do not use amplifiers, combiners, filters or splitters that are not optimized for 75 Ω systems. Control and Power Connections Prior to installation, you should decide if you want to use the factory configuration or an alternate one.

  • Page 19: Default Configuration

    Default Configuration The DXE-RFS-2 default configuration uses terminals A & B for the BCD directional control interface and terminal C for operational and active element power. The DXE-CC-8A provides the operational power as well as the 2-bit BCD interface used for directional control. A user-supplied 4- conductor cable is needed to connect the DXE-RFS-2 and the DXE-CC-8A.

  • Page 20: Dxe-Rfs-Ts3P Default Connection Diagram Using Factory Jumper Settings

    DXE-RFS-TS3P Default Connection Diagram Using Factory Jumper Settings Shown with optional DC Pass Through Lightning Protection, optional DXE-RFCC-1 Feedline Current Choke, and optional DXE-RPA-1 HF Preamplifier...

  • Page 21: Alternate Configurations

    Alternate Configurations The DXE-RFS-2 can be configured to use the coaxial feedline for power or directional control, but not simultaneously. Diagram 2 illustrates one way to use the feedline for directional control with optional hardware. Other configurations are possible. Do not make contradictory jumper settings. Any alternate configuration requires changing the internal jumpers from their default settings.

  • Page 22: Diagram 2 - Alternate Configuration

    Diagram 2 - Alternate Configuration All Element feedlines, delay lines and station feedlines must be 75 Ω coaxial cable. Element feedlines can be any length, but must be equal. (Not drawn to scale) RFS-3P Alternate Configuration, Requires Internal Jumper Changes Uses Optional DXE-FVC-1 to control direction using the feedline Uses DXE-CC-8A BCD interface to control the FVC-1 (may also use ground closure) Power to the RFS-2 uses terminal C of the CC-8A (switch positions 5 to 8)

  • Page 23: Diagram 3 - Alternate Configuration

    Diagram 3 - Alternate Configuration All Element feedlines, delay lines and station feedlines must be 75 Ω coaxial cable. Element feedlines can be any length, but must be equal. (Not drawn to scale) RFS-2 Alternate Configuration, Requires Internal Jumper Changes Uses optional DXE-FVC-1 to control direction using feedline.

  • Page 24: Dxe-Rfs-2 And Active Element Power

    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 200 mA current is required. The default configuration uses Terminal C on the 5-position plug for power. The DXE-CC-8A uses positions 5 through 8 to power and control the DXE-RFS-2.

  • Page 25: Internal Jumper Selection

    Forward Rear Voltage on Coax or Direction Direction Direction J12 Term C Shift Element 1 Element 3 None 0° Element 2 Element 4 +12 Vdc 90° Element 3 Element 1 -12 Vdc 180° Element 4 Element 2 12 Vac 270° Table 5 - Differential Voltage Control Matrix Internal Jumper Selection To access the DXE-RFS-2 jumper blocks, remove the 6 screws holding the connector plate of the...

  • Page 26: Powering Through The Feedline

    Powering Through the Feedline To power the DXE-RFS-2 from the feedline, move the JMP1 jumper block from the top and middle pins of the header to the lower and middle pins. When the feedline is used for power, you can use either Terminal C on J12 for directional control using differential voltages, or Terminals A &...

  • Page 27: Front-To-Rear (Null) Optimizing

    the noise along with the signal. It is always best to use the least gain possible. Depending on conditions, a preamplifier can cause receiver overload; this may require an attenuator or bypassing the preamplifier. The DXE-RPA-1 HF Preamplifier has better dynamic range than most receivers and can be used to compensate for the decrease in array signal output.

  • Page 28: Normal Receive Four Square Operation

    Normal Receive Four Square Operation When the Receive Four Square system is functioning properly, low or medium power daytime AM Broadcast ground wave signals should be alternately attenuated or improved with directional switching. However, strong sky wave signals arriving at high angles of propagation will show very little signal level change as different directions are selected on the Receive Four Square.

  • Page 29: Receive Four Square Troubleshooting

    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 30 A) Broken and/or shorted conductors due to animal, weather or other damage, including chewed, punctured, stretched and broken control and power lines and/or feedlines for the system and each antenna. Also, screws in the green removable connectors can inadvertently be tightened onto the insulation of control or power conductors.

  • Page 31: Additional Receive Four Square Control Troubleshooting

    4) If the CC-8 or CC-8A 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-CC-8A is available from DX Engineering. Continue troubleshooting the array control with a good CC-8 or CC-8A or by using a 1A fused power source.
  • Page 32 + 10 to 18 Vdc is found, then the Active unit may need to be serviced or replaced. New DXE- AVA-2 units are available separately by calling DX Engineering. 10) If all Active Verticals tested provide the same signal level, then change switching voltages to activate the other ports, one at a time, and test each RFS unit port, using one of the good antennas, testing for the same level of reception.

  • Page 33: Optional Items

    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 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 That's the vinegar smell. The acetic acid causes the corrosion. DX Engineering has located a Neutral Cure RTV made right here in Ohio that is non-corrosive and is safe for sealing those baluns and other electronic gear that are going to be out in the weather.

  • Page 36: Technical Support And Warranty

    DXE-900031 - Automatic Wire Stripper/Crimper/Cutter, 24-10 Ga. Our DX Engineering wire stripper uses a spring-loaded design to make quick work of wires ranging from 24 to 10 gauge. Just insert the wire, squeeze the handle, and listen for the click. That’s the sound of another perfect wire stripping job performed in about 2 seconds- a fraction of the time it takes your pocket knife to do the same job.

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