Receive Four Square System
Contents
1. ENGINEERING Receive Four Square System DXE RFS 2P DXE RFS TS2P DXE RFS 2P INS Revision 2 DXE RFS TS2P Components Shown DX Engineering 2008 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 D XEngineering com Table of Contents Introduction DXE RFS 2P Receive Four Square Array Controller and Switch Package DXE RFS TS2P 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 Site Selection in Relation to Noise Sources Ground System Lightning Protection Sizing the Array Four Square Layout System Operational Overview Installation Active Antenna Elements Station Feedline Active Antenna Feedline and Delay Lines Active Antenna Feedlines Delay Lines Control and Power Connections Default Configuration Alternate Configurations Supplying Power Using the Feedline Directional Control Using the Feedline DXE RFS 2 and Active Element Power Directional Control Internal Jumper Selection Default Jumper Configuration Settings Powering Through the Feedline Directional Control Using the Feedline Optimizing the Array Front to Rear Null Optimizing Optional Items Technical Support and Warranty Figures Tables and Diagrams Azimuth Pat2. wX position that will drastically Hoo reduce or eliminate it ye 21 Optional Items DXE RPA 1 Receiver Preamplifier 0 3 35 MHz This is the best HF low noise amplifier available The RPA 1 is optimized for 0 3 35 MHz operating range The push pull amplifier design and robust components enable it to withstand high signal levels and operate when you need it most The dynamic range of the RPA 1 is better than most receivers The RPA 1 is suitable for indoor or outdoor installation with the option of being powered through the coaxial feed The metal housing provides shielding and improved lifespan The unit uses RCA type phono jack and CATV F connector for the input and output connections and has a relay that automatically bypasses the amplifier when dc power is removed Benefits e Push pull operation eliminates harmonic distortion High quiescent current increases ability to handle strong signals without distortion or overload Meticulous craftsmanship and durable components provide superior dynamic range RCA type phono jack and type F connector ease installation Simplified switching automatic bypass eliminates gain when dc power is off 10 18 Vdc power using power connector or through the coax 10 18 Vdc through coax enables remote operation at antenna DXE RFCC 1 Receive Feedline Current Choke 50 to 75 Ohm 300 kHz to 30 MHz If you wish to reduce feedline radiation and improve reception a Feedline Current Choke is recommend
3. 70 degrees F And it doesn t smell like vinegar e 3 3 oz Tube e Black This part is classified hazardous and is limited to domestic UPS Ground shipping only DXE SNS6 25 Watertight Coax Connector Snap N Seal for CATV F 6 Cable 25 pieces Snap N Seal is an environmentally sealed CATV F coax connector system for harsh environments The connectors have a unique 360 degree radial compression system that offers the signal leakage protection required for high performance receive systems Quad sealed system prevents moisture from migrating into the connection 360 degree radial compression provides superior RF integrity 95dB typical 60 bonded foil cable e Easy cable preparation a Pr Connector to cable retention of 40 Ibs minimum a S i Superb impedance match to 1 GHz Manufactured of high quality 360 brass cadmium plated with yellow chromate coating for maximum corrosion resistance e UV resistant plastic and O rings provide a reliable environmentally sealed connector An installation tool such as the DXE SNS CT1 is required to install the connectors Normal crimping tools or pliers will not work DXE SNS CT1 Compression Tool for Snap N Seal 75 Ohm Coax Connectors Ratchet compression tool for installing Snap N Seal 75 ohm Coax connectors Ordinary pliers will not install these connectors properly 30 DXE CW9 1K _ Shielded Control Wire Economically Priced 9 Conductor 1000 ft Reel Economically priced DXE CW9 1K is a 100
4. AWG Aluminum Braid Wire 60 Coverage Jacket PE Flooded for Underground Nominal Diameter Over Jacket 0 272 in Nominal Jacket Thickness 0 030 in Electrical Properties Impedance 75 0 3 0 Ohms Velocity of Propagation 85 0 Nominal We recommend the use of Snap N Seal connectors to ensure a high quality and weather resistant feedline connection The proper tool must be used to install these connectors DXE CPT 659 oax Cable Stripper for CATV F 6 RG 6 and RG 59 coax Prepares CATV F 6 RG 6 and RG 59 coax cable for the installation of an F type connector e One step cutting motion Precision cut J e No nicks or scratches to conductor e Includes 1 replacement blade DXE RTV598335 Permatex Black RTV Sealant Non Acetic 3 3 oz Tube Black DX Engineering Approved RTV Sealant We have all used RTV to seal water out of things right Have you ever sealed a piece of electronic gear with it then opened it some time later to find that it had still managed to become corroded inside Guess what It s not the rain that corroded it It s the RTV Normal RTV gives off acetic acid when it cures 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 Applies just like normal RTV dries in one hour and cures in 24 hours at
5. Control Console supplies the nominal 12 Vdc operational voltage as well as the 12 Vdc BCD control voltage The operational voltage powers the DXE RFS 2 Control Unit which subsequently powers the active receive elements The BCD switching voltages cause the DXE RFS 2 to change the receiving direction of the array 13 The DXE CC 8 Control Console is configured by default to output the BCD control voltages needed by the DXE RFS 2 Only the last four positions of the DXE CC 8 are used LEDs 5 through 8 because the DXE RFS 2 only requires a 2 bit BCD control logic The array is powered when the DXE CC 8 has selected LED 5 6 7 or 8 The default direction for the array toward Element 1 is selected when LED 5 on the DXE CC 8 is illuminated When positions 6 to 8 are selected on the CC 8 the array switches directions according to the directional control matrix in Table 4 Refer to Diagram 1 for default connection details The DXE RFS 2 distributes the operating power to the active elements through the individual element feedlines The active elements do not work without power Cutting power to the DXE RFS 2 also cuts power to the active elements which causes the DXE AVA 2 to ground the vertical element Operating with the DXE TVSU 1 Sequencer inserted into the CC 8 C to the RFS 2 C terminal makes this power switching function automatically An alternate configuration which uses the feedline coax for either the operational power or the directi
6. The FVC 1 also has two LED indicators red and green which indicate the presence and polarity of the output control voltage being used They are directional indicators that can be read at a convenient distance and can aid in troubleshooting Features Safe external 12V heavy duty power pack Metal Housing superior shielding rugged and easy mounting Convenient installation mounts anywhere in your shack Rugged Control Connector reliable solder less connections Internal thermal reset fuse full protection against accidental shorts Flexible logic input BCD or standard one of four high or low actuated Operation indicators bright red and green LED indicators can be seen at a distance PPC IS 75FB 18 PolyPhaser Lightning Protector 75 ohm 18V DC Pass Type F Connectors The IS 75FB 18 was chosen to compliment the line of receive only antennas from DX Engineering This is a 75 ohm lightning protector that has type F connectors and passes 18 VDC for control power at the antenna units e Complies with IEEE 802 3 500 3 a Broadband low VSWR and loss 2 Multi strike capability D Low voltage thresholds Low throughput energy DXE CAVS 1P V Bolt Saddle Clamp 1 2 in to 1 3 4 in O D Applications This V Clamp is made in one size that fits tubing from 1 2 to 1 3 4 O D as used in antenna construction The supplied V bolt is long enough to attach tubing to thick plates and is made with anti corrosive properties The cast rippled surf
7. This will allow easier wire replacement or servicing as needed When pushing the connector back in place ensure you press straight inward 18 Default Configuration The DXE RFS 2 default configuration uses terminals A amp B for the BCD directional control interface and terminal C for operational and active element power The DXE CC 8 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 8 Choose a 4 conductor cable 3 ground of at least 22 gauge for lengths up to 1500 feet If you use a cable with more conductors it is a good idea to tie the unused conductors to ground Use point to point wiring matching the terminal labels at each end Economically priced DXE CW 9 is a 9 conductor Shielded Control Wire which may be used DXE CW 9 is made of 24 AWG wire Since the DXE RFS needs four lines the DXE CW9 could be doubled up example orange amp orange white wires connected together at both ends to increase the wire gage size and increase the length of operation 19 DXE ARAV2 Element 1 a DXE ARAV2 Zo Element m4 H 75 Ohm Coaxial ai Cable Cable DXE RFS 2 75 Ohm 75 Ohm Coaxial Coaxial Cable DXE ARAV2 DXE ARAV2 Element N E y 3 Ee DXE TVSU 1 N Pen DX scovence unn n ar H ae TVSU 1 Sequencer Connect CC 8 Termi
8. 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 O D A good ground system improves the array performance and enhances lightning survivability It is 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 initial 4 ft to 6 ft 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 If a good ground cannot be established use an optional DXE RFCC 1 Receive Feedline Current Choke that will further decouple the feedline from the antenna and reduce common mode current and associated noise from the feedline Lightning Protection While amateur radio installations rarely suffer damage from lightning the best protection 1s 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 prote
9. ground as possible but above any standing water or snow line Ground the ANT negative terminal to an adequate ground Active Antenna Elements If you are planning to use the array on 160m a jumper in the active antenna matching units should be changed Placing a jumper on LIMF will peak the array sensitivity response for use on 160m with little effect on 80m when the recommended array side lengths in Table 2 are used When 14 doing this the sensitivity for the AM broadcast band will be reduced All four active elements in the array must have identical jumper settings For access to the jumpers in the active matching units remove the 2 screws on each side of the case and remove the bottom The circuit board and jumper headers will be visible as shown in Figure 3 By default there are no jumpers across any pins Place a jumper across LIMF Do not jumper any other positions See the Active Antenna User Manual for more information about additional peak response jumper settings ime Jumper Shown in KE L1MF for 160 Meter Operation Figure 3 Active Element LIMF Jumper Locations Please read the manuals for the DXE ARAV Active Elements and DXE CC 8 Controller so you understand their operation before proceeding Station Feedline Active Antenna Feedline and Delay Lines The weakest link in an antenna system such as the DXE RFS 2 is often the coax cable connections All connections must be high quality and weather tight to preve
10. performance across a wide frequency range This side length is optimal for 40m according to Table 2 The array worked from 3 MHz to 15 MHz As shown on the following page the patterns stay clean with good directivity and front to rear performance The elevation angle is 15 degrees for all patterns Amplification is required below 3 MHz Note The RFS 2 Receiving system must 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 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 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 3 MHz 6 MHz iwl Side Length 2wl Side Length Avg Gain 36 73 dB Avg Gain 22 11 dB 9 MHz 12 MHz wi Side Length Awl Side Length Avg Gain 14 16 dB Avg Gain 10 62 dB 15 MHz 5wl Side Length Avg Gain 10 16 dB Azimuth patt
11. them to the support pole or mast rather than allowing them to hang from the connectors 17 It is important to use 75 Q feedline to the operating position from the DXE RFS 2 Do not use amplifiers combiners filters or splitters that are not optimized for 75 Q systems Control and Power Connections Prior to installation you should decide if you want to use the factory configuration or an alternate one If you have the DXE RFS 2P system with the DXE CC 8 Control Console no other equipment is needed for powering the DXE RFS 2P the active elements or controlling the receive direction of the DXE RFS 2P The DXE RFS 2P has been factory set to work with the DXE CC 8 If you have a stand alone RFS 2 several configuration options need to be considered before installation J12 is the 5 terminal connector plug on the front panel of the DXE RFS 2 It is labeled G A BCG Ground Both G terminals are common ground 2 bit BCD directional control inputs Depending on jumper configuration terminal C can also be used for directional control using differential voltages The coax must then be used to supply operational power The DXE CC 8 uses the same 5 terminal plug labeled BCD The terminals use the same names E _s i Ci S i s Gi2z2345678G GABCG MADE IM USA CC 8 RFS 2 On both the DXE CC 8 and the DXE RFS 2 the green connectors are in two parts and the top part can be removed by pulling it straight off
12. your wiring job e Spring loaded design e Strips wires ranging from 24 to 10 gauge e built in wire cutter and crimper DXE 11055 Klein Kurve Wire Stripper Cutter 11055 18 22 AWG Klein Tools Klein Kurve wire strippers are ideal for stripping solid 10 18 AWG and stranded 12 20 AWG wire cleanly and easily The 7 1 8 in strippers also have precise shear type blades to cut copper wire nicely easy to read markings on both sides and extra soft grips and curved handles for comfort 31 Technical Support If you have questions about this product or if you experience difficulties during the installation contact DX Engineering at 330 572 3200 You can also e mail us at DXEngineering DXEngineering com For best service please take a few minutes to review this manual before you call 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 1s proved to be other than as warranted no allowance shall be made for any labor charges of Buyer for replacement of parts adjustment or repairs or any other work unless such charges are authorized in advance by DX Engineering If DX Engineering s products are claimed to be defective in material or workmanship DX Engineering shall upon prompt noti
13. 0 foot box of high quality shielded outdoor FTP Foil Twisted Pair Cat5e cable It features 4 Twisted pairs of 24 AWG solid wire with Al foil shielding plus a solid tinned copper drain wire providing a total of 9 conductors for DC switching applications It has a polyethylene jacket and is rated for direct burial This cable is ideal for DX Engineering Remote Antenna Switches and Four Square arrays and should be considered for any low current custom remote switching application you have such as receiving antenna arrays A nice feature is the rip cord which allows for easy stripping of the heavy jacket without worry about nicking or accidentally cutting the conductors Excellent for use in all outdoor applications of switching networking data transfer and phone lines As a data transfer line it supports 10 100 1000Mbps The Shielded Control Wire may also be purchased by the foot call DX Engineering for details 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 An adjustable wire length guide helps you make uniform strips and a built in wire cutter and crimper helps you complete
14. 8 DX Engineering DXE Hot Rodz Maxi Core THUNDERBOLT Antenna Designer Yagi Mechanical and Gorilla Grip Stainless Steel Boom Clamps are trademarks of PDS Electronics Inc No license to use or reproduce any of these trademarks or other trademarks is given or implied All other brands and product names are the trademarks of their respective owners Specifications subject to change without notice 32
15. Antenna Feedlines Use 75 Q coax from each antenna element to the DXE RFS 2 The four feedlines from the DXE RFS 2 phasing unit to the active elements can be any length needed to accommodate the size of the array but must all be the same length velocity factor and type Note the orientation and numbering of the elements by using Figure 2 Be sure the appropriate antenna element is connected to the proper ANT connector on the phasing unit The default zero control voltage forward direction 1s towards Element 1 Element 3 is the rear or null direction Delay Lines The DXE RFS 2 uses a time delay system not a traditional phasing system Delay line lengths are dictated by array dimensions rather than operating frequency This results in phase being correct for a rearward null at any frequency This system is especially effective when used with DX Engineering ARAV active elements User supplied passive elements can also provide exceptional performance for single or dual band operation where high dynamic range is required The DXE RFS 2 phasing unit has three sets of delay line connections marked DLY1 DLY2 and DLY3 Each of these connection pairs will have a specific length of coax acting as a jumper between the two connectors Jumper electrical length 1s critical Careful measurements and the use of 75 Q coax with a known Velocity Factor VF is very important Solid Teflon or polyethylene dielectric coax cable has a VF of approximately 0 66 Foa
16. ace of the saddle will clamp the tubing securely to a flat surface however for high torque applications please use our standard U Bolt Saddle Clamps e Used to clamp 1 2 to 1 3 4 O D tubing e Designed for attachments that don t require resistance to torque e V bolt made from high strength 18 8 stainless steel 7 e V saddle cast from 535 aluminum with rippled surface The use of an Anti Seize compound is HIGHLY recommended to achieve proper torque and prevent galling ial DXE 81343 NSBT8 Anti Seize amp Never Seez An Anti seize compound MUST be used on any Stainless Steel nuts bolts clamps or other hardware to prevent galling and thread seizure Any of these products can be used for this purpose DXE 81343 Anti Seize 1 oz Squeeze Tube DXE 8 1464 Anti Seize 8 5 oz Aerosol Can DXE NSBT8 Never Seez 8 oz Brush Top DXE NMBTS8 Never Seez 8 oz Brush Top Marine Grade These products are limited to domestic UPS Ground shipping only _ 29 DXE F6 1000 75 ohm F 6 Style Direct Bury Coax 1000 ft Spool Hi Quality 75 Ohm F6 type Flooded Coax Sold by the spool or as Custom Cable Assemblies Center Conductor 18 AWG Copper Clad Steel Nominal Diameter 0 040 in Dielectric Gas Expanded Polyethylene Nominal Diameter Over Dielectric 0 180 in Shield 1st Shield Aluminum Polypropylene Aluminum Laminated Tape with overlap Bonded to the Dielectric Nominal Diameter Over Tape 0 187 in 2nd Shield 34
17. amp B Directional Control Using the Feedline To use the feedline for directional control move the JMP2 jumper block from the top and middle pins to the bottom and middle pins When you use the feedline for directional control you must also set both JMP3 and JMP4 to use differential voltage by moving the jumper blocks to the top and middle positions Jumper blocks must be moved together as a pair A suitable controller such as the DXE FVC 1 must be used to couple the directional control voltages onto the coax as shown in Diagram 2 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 Connecting the antenna should result in a noticeable increase in noise If so the array signal level is sufficient and further optimization or amplification may not be needed If the array is used on 160m or below the Active Antenna internal jumper should be set as shown in the Installation Section on page 12 of this manual If the array still lacks sensitivity on the lower bands then a preamplifier with high dynamic range should be used to com
18. ce thereof issue shipping instructions for return to DX Engineering transportation charges prepaid by Buyer Every such claim for breach of these warranties shall be deemed to be waived by Buyer unless made in writing The above warranties shall not extend to any products or parts thereof which have been subjected to any misuse or neglect damaged by accident rendered defective by reason of improper installation damaged from severe weather including floods or abnormal environmental conditions such as prolonged exposure to corrosives or power surges or by the performance of repairs or alterations outside of our plant and shall not apply to any goods or parts thereof furnished by Buyer or acquired from others at Buyer s specifications In addition DX Engineering s warranties do not extend to other equipment and parts manufactured by others except to the extent of the original manufacturer s warranty to DX Engineering The obligations under the foregoing warranties are limited to the precise terms thereof These warranties provide exclusive remedies expressly in lieu of all other remedies including claims for special or consequential damages SELLER NEITHER MAKES NOR ASSUMES ANY OTHER WARRANTY WHATSOEVER WHETHER EXPRESS STATUTORY OR IMPLIED INCLUDING WARRANTIES OF MERCHANTABILITY AND FITNESS AND NO PERSON IS AUTHORIZED TO ASSUME FOR DX ENGINEERING ANY OBLIGATION OR LIABILITY NOT STRICTLY IN ACCORDANCE WITH THE FOREGOING DX Engineering 200
19. ction 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 coax feedline and control lines 11 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 Determine the size of the array by considering the availability of appropriate space frequency coverage desired and the near proximity to undesirable noise sources transmitting antennas and other structures If there are no space constraints follow the array side length recommendations in Table 2 for excellent performance Side lengths longer than the optimal lengths shown will move the peak sensitivity of the array toward the lower frequency For example if you are most interested in 160m performance with occasional use on 80m make the side lengths longer than the optimal 98 feet shown for 160m and 80m This will improve 160m performance reduce sensitivity on 80m somewhat but less than sizing the array exactly for 160m Optimal S
20. ed 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 The advantages of using an FCC e Prevents unwanted RFI by eliminating feedline current and radiation All power goes to the antenna improving efficiency J e Reduces noise or unwanted signals picked up by the feedline e Overcome a less than optimal ground system The DX Engineering RFCC 1 receive feedline common mode choke is the most effective solution to common mode noise or unwanted signal ingress available to date The DX Engineering RFCC provides thousands of ohms isolation between the input and output coaxial shield connections while passing desired signals including dc or low frequency ac control signals The RFCC has extremely high isolation impedance which effectively blocks common mode noise or unwanted signals even in the presence of very poor grounding Low noise receive antennas are traditionally located away from electrical wiring and other noise sources Unfortunately noise and other unwanted signals have a direct path to your low noise antenna through the feedline shield connections between the station equipment and antenna Unwanted signals can also energize the outside of the feedline shield and this undesired signal energy can be conducted directly to the receiving anten
21. equired Not Supplied with the DXE RFS 2P DXE CAVS 1P Mounting Clamp for DXE RFS 2 Pre drilled mounting bracket accepts pipe sizes from 1 2 inch to 3 4 inches Four Conductor Power and Control Cable for DXE RFS 2 Default Configuration 4 conductor cable 3 plus ground 22 gauge minimum Alternate configurations use a l or 2 conductor cable Economically priced DXE CW 9 is a 9 conductor Shielded Control Wire which may be used 75 Q Coax Cable CATV F6 Style Connectors and Installation Tools When calculating cable length include connections from the phasing unit to each active element the 3 delay lines and the distance to the operating position You must use 75 Q coax with a known velocity factor VF for all connections We recommend using a high quality 75 Q flooded F6 type coax such as DX Engineering part number DXE F6 1000 Flooded style cables automatically seal small accidental cuts or lacerations in the cable jacket Flooded cables also prevent shield contamination and can be direct buried Feedline connections must have good integrity and be weather resistant We recommend Snap N Seal type F connectors The complete DXE RFS 2 system including feedline connections requires 16 type F connectors DXE SNS6 25 contains 25 Snap N Seal connectors enough for the entire array plus nine spare connectors Note The DXE CPT 659 stripping tool prepares F6 style cable for connectors in one easy and clean operation and comes with an e
22. erns for an optimized 40 meter array Note the very wide bandwidth and good front to rear pattern achieved throughout the frequency range Site Selection Site selection is important The DXE RFS 2 system can be positioned as close as 1 10 wavelength to transmitting antennas The DXE ARAV2 1P Active Elements are bypassed to ground when power is turned off A programmable sequencer such as the DXE TVSU 1 is required for close spacing requirements The DXE TVSU 1 is included in the DXE RFS TS2P complete Receive Four Square Array Package Significant pattern distortion or coupling may result from close spacing To prevent pattern degradation or re radiation of electrical noise or other interference separation of 1 2 wavelength at the lowest operating frequency is ideal See Figure 1 The goal is to do the best you can by balancing all the factors Element 4 Element 1 1 10 Wavelength _ gt Minimum Separation Element 3 Element 2 TR INININ UN INURL RUN DR NUR AD VA AVAAA AAA AAA AAA 1 10 wavelength is the minimum distance to any transmitting antenna from the Four Square perimeter 1 2 wavelength is the best distance to prevent coupling to other antennas Figure 1 Site Selection Clear Distance Proximity to Transmitting Antennas The DXE ARAV2 1P active elements and your transmitting antenna need only minimal physical separation to maintain safe power levels when the DXE TVSU 1 sequencer is u
23. g directions Element 1 is the default forward element Element 3 is the rear or null element e Performance of the RFS 2 can noticeably decrease if structures radiating even small amounts of noise or signals are within 1 wavelength of the array Element 4 Element 1 Optional Optional Feedline Current Fre Amp Choke To Radio Receiver RPA 1 75 Ohm RFCC 1 75 Ohm Coaxial Coaxial Cable Cable Dela RFS 2 __ new Power and Power and Fo Control Control CC 8 Cable TVSU 1 Cable Element 3 Element 2 Figure 2 Layout of the DXE RFS TS2P Four Square System e Measure side to side and then corner to corner to ensure the element locations are square e Normally the RFS 2 phasing unit is installed near the center of the four array elements above any standing water or snow line with the connector side facing down The placement of the RFS 2 unit is not critical however the feedlines to each of the active elements must be equal e If you mount the RFS 2 on a wood post it should be grounded to a separate ground rod System Operational Overview The DXE RFS 2P system is comprised of the DXE CC 8 Control Console and the DXE RFS 2 Control Unit These units interconnect and work together using factory default settings If you purchased only the DXE RFS 2 Control Unit you must provide the power and switching voltages to the DXE RFS 2 Please refer to the appropriate tables and the configuration diagrams in this manual for details The DXE CC 8
24. h direction Terminal C is used to power the DXE RFS 2 so it is always on Forward Direction _ Rear Direction A B C CC 8 E s nateg Element 1 Default Element 3 Default 0 0 1 emna kemend 1 o i eooo Oo emaa N emen ee E Element Table 4 BCD Directional Control Matrix 1 Equals 12 Vdc a Alternatively directional control using differential voltages can be done through the coax feedline or Terminal C on the DXE FS 2 This requires the default jumper settings to be changed See the next section for jumper settings Directional control through Terminal C requires only one conductor plus a ground return path That return path can be the coax shield or an additional conductor specifically dedicated to that purpose Terminal C cannot be used for powering the DXE RFS 2 if it is being used for directional control 24 Forward Rear Voltage on Coax or Direction Direction Direction a a 12 Term C ae ae Element 1 Element 3 Nme 12 Vde w Element 3 Element 1 12 Vdc 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 DXE RFS 2 unit to the enclosure Pull on the plate to separate it from the enclosure The jumper blocks should be visible and oriented as shown in Figure 5 Important Note You cannot use coax or any other conductor for multiple functions If you are going to u
25. ide Min Side Max Side o 8 30 7 _ 160 80 183 360 9 Table 2 Array Side Lengths If you have limited space a carefully installed and amplified DXE RFS 2 can be used on multiple bands with very small side lengths At smaller side lengths careful construction using precise measurements is critical On a fixed size array as frequency is decreased the array signal output decreases along with array sensitivity Eventually the received ambient noise signal level will decrease to a point where it is below your receiver s noise floor This comes from two effects e Elements become electrically shorter reducing element sensitivity e Element spacing becomes smaller in electrical degrees reducing array sensitivity Side lengths at 1 10 wavelength on 40m would only be 14 ft Although usable amplification would be required In addition the construction of a very small array is extremely critical Side lengths must be perfectly symmetrical The delay lines must be directly measured for electrical length and cut to exact lengths The ground system must be effective Even at this small spacing the array will have useful front to rear performance and directivity 12 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 e The diagonal corners of the square should point in the most desirable receivin
26. lay contact reliability The DXE RFS 2P includes the DXE CC 8 Receive Four Square Switch controller The CC 8 interfaces to the RFS 2 through a 3 or 4 wire cable to select one of four directions on the RFS 2 and to power the active elements Economically priced DXE CWS9 is a 9 conductor Shielded Control Wire which may be used DXE RFS TS2P Complete Receive Four Square Array Package for Normal Spacing to Transmit Antennas Complete Receive Four Square Array package for Close Spacing to Transmit Antenna e W8JI design e Operates from 100 kHz to 30 MHz e Excellent directivity in a small space for better signal to noise ratio e Switchable in four 90 degree spaced directions e Reduced susceptibility to high angle signals compared to EWE Flag Pennant or K9AY arrays DXE RFS TS2P is a complete Receive Four Square Array Package for Close spacing to transmit antenna which includes e 1 DXE ARAV2 4P Package of four Active Receive Vertical Antennas w Internal Antenna Disconnect Relays e 1 DXE CC 8 8 Position Control Console e 1 DXE RFS 2 Receiving Four Square Antenna Switch e 1 DXE TVSU 1 Time Variable Sequence Unit e 1 DXE F6 1000 CATV F 6 Style Coax 75 ohm F6 Flooded for Direct Burial 1000 Spool e 1 DXE CPT 659 CATV F 6 RG 6 and RG 59 Coax Cable Stripper Includes 1 Replacement Blade e 25 DXE SNS6 25 Snap N Seal 75 Ohm Coax Connectors for CATV F 6 Cable e 1 DXE SNS CT1 Crimp Tool for Snap N Seal 75 Ohm C
27. lement 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 8 uses positions 5 through 8 to power and control the DXE RFS 2 The default direction is selected when LED 5 is illuminated This setting provides operating voltage on Terminal C of the DXE CC 8 which is connected to Terminal C on the DXE RFS 2 The active elements do not work without power See Table 4 note that C has voltage in all four positions If the TVSU 1 Sequencer is used it will provide keyed power for the DXE RFS 2 for the active verticals Alternatively the coax can be used to power the elements This requires the default jumper settings to be changed See the next section for alternate jumper settings You must provide a way to couple this voltage on the feedline Directional Control The default configuration of the DXE RFS 2 phasing unit uses a 2 bit 12 Vdc BCD interface scheme to switch directions through a user supplied 4 conductor cable connected to the DXE CC 8 The default direction without applied control voltage is in the direction of Element 1 Element 3 is the default rear or null direction Table 4 shows the array direction the truth table for the BCD interface A amp B and the status of the LED indicators on the DXE CC 8 for eac
28. 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 Nighttime can bring a dramatic increase 10 in the overall noise level as noise propagates via the ionosphere from multiple distant sources Since the noise is external to the antenna directivity can reduce noise intensity Consider these things about noise sources e 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 e 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 receiving antennas as far from noise sources such as power lines as possible Ground System The ARAV2 1P Active Elements work well with just a single copper ground rod placed as close as possible to the mounting pipe The mounting pipe can be used as the system ground if the pipe is an adequate ground It is recommended that a 3 4 or larger rigid copper water pipe although conventional copper coated steel rods may also work Depending on soil conductivity you can expect better performance with multiple ground rods spaced a few feet
29. med coax cables typically range anywhere between 0 75 and 0 90 VF depending on the ratio of air to dielectric material in the cable core 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 Q 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 The first step is to determine the required electrical length of DLY3 This is based on the corner to corner or diagonal distance between two diagonal corner elements of the square forming the array You can directly measure this distance or it can be calculated by multiplying the side length of the array by 1 4142 The electrical length of delay line DLY3 should be slightly shorter than the actual physical distance between the two diagonal corners of the array An electrical length 95 of the physical distance works well diagonal distance times 0 95 Table 3 shows these calculations for three common side lengths 16 Diagonal Factored 0 95 Side Length in Physical Length Electrical Length Feet in Feet in Feet DLY3 Physical Length in Feet 0 85 VF 135 160m 190 9 181 4 154 2 98 160m amp 80m 138 6 131 7 111 9 70 80m 990 OD Table 3 Examples of DLY3 Required Length After calculating the required electrical length you must include the VF of the coax being used when deter
30. mining the correct physical length of DLY3 Multiply the factored electrical length by the VF The result is the correct physical length for DLY3 See Figure 4 and the sidebar for an example Note These calculations are in feet not feet and inches a Side Length To find the physical length of DLY3 calculate the diagonal length of the array by either directly measuring the diagonal or by multiplying the array side length by 1 4142 DLY3 will be significantly shorter than the actual physical length The diagonal length is first multiplied by 0 95 This gives the factored electrical length for DLY3 Next multiply the DLY3 electrical length by the VF of the delay line coax The result is the correct physical length for DLY3 Figure 4 Diagonal Dimension 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 Q coax The correct physical length for DLY3 is 102 77 feet or 102 feet 9 inches Delay lines DLY1 and DLY2 must be half the length of DLY3 Make DLY1 and DLY2 as close to half the physical length of DLY3 as possible To avoid performance degradation due to inconsistent coax construction all the delay line coax should be cut from the same spool Delay line cables can be neatly coiled in a 1 1 2 ft diameter coil Support the weight of the cables by taping or securing
31. na This can reduce antenna directivity Unless you have a perfect zero resistance RF ground at the antenna some of the common mode noise or unwanted signals from the feedline shield will make it into the antenna The RFCC is effective from 300 kHz to 30 MHz It comes with standard CATV type F female connectors although it can be used in any 50 to 75 ohm receiving system The RFCC is a passive device therefore requires no power to operate 28 DXE FVC 1 Feedpoint Voltage Coupler The FVC 1 provides an interface for standard control switches such as the DXE CC 8 or your own arrangement to voltage multiplexed antenna systems This interface system will provide the voltages required to remotely select up to four antennas or four directions through receiving or low power transmitting feedlines It provides fuse protected OV 12 Vdc 12 Vdc and 12 Vac output voltages through a panel mounted feedline connector These voltages can be used to EN provide four direction switching of an antenna array either through the feedline or on a single wire supplemental l control line Control is done using a standard 1 of 4 BCD or switch closure interface gie 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 8 Control Console can provide the 1 of 4 and BCD input used by the FVC 1 or you can use your own switch
32. nal C to F iz TVSU 1 Pre Amp Power In Center Pin iz RFS to CC 8 Connect CC 8 Terminal Gnd to CC 8 Should without TVSU 1 TVSU 1 Pre Amp Power In Sleeve be Grounded t a a gt G to G Connect Pre Amp Power Out Center Pin to to Station an AtoA RFS 2 Pin C Ground BtoB 75 Ohm DXE CC 8 Ctoc Coaxial Cable Optional PPC IS 75FB 18 Optional DXE RFCC 1 Optional DXE RPA 1 75 Ohm DC Pass Though Lightning Feedline Current Choke HF Preamplifier Coaxial Protection i m Cable To Receiver DXE RFS TS2P Default Connection Diagram Using Factory Jumper Settings Shown with optional PPC IS 75B 18 DC Pass Through Lightning Protection optional DXE RFCC 1 Feedline Current Choke and optional DXE RPA 1 HF Preamplifier 20 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 Supplying Power Using the Feedline If you use the feedline to supply operational power then directional control must be done using the J12 connector There are two ways to do directional control through J12 when using the coax for power e Differential voltages 12 Vdc amp 12 Vac using terminal C This can be done using a 1 or 2 conductor cable Economically priced DXE CW 9 is a 9 conductor Shielded Cont
33. nt contamination and corrosion which can cause the feedline impedance to change This can affect the signal to noise ratio and the directivity of the array In addition the DXE RFS 2 uses the shield as a ground return path for the active element power Note The total loop resistance of the ground path must be under 30 Q for reliable operation 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 2 system has been designed to use only 75 Q coax High quality flooded 75 Q CATV F6 type coax is recommended DXE F6 1000 Flooded cables automatically seal small accidental cuts or lacerations in the jacket 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 DXE SNS6 25 contains 25 Snap N Seal connectors enough for the entire array plus some spares The Snap N Seal connectors cannot be installed with normal crimping tools or pliers so you must use 15 an installation tool like the DXE SNS CT1 available from DX Engineering for proper connector installation Active
34. o use ground closure Power to the RFS 2 uses terminal C of the CC 8 switch positions 5 to 8 Route power from the TVSU 1 Pre Amp Power IN jack from CC 8 Terminal C Connect the TVSU 1 Pre Amp Power OUT jack to the power wire for the RFS 2 ZZ Diagram 3 Alternate Configuration All Element feedlines delay lines and station feedlines must be 75 Ohm coaxial cable Element feedlines can be any length but must be equal Not drawn to scale _ DXE ARAV2 DXE ARAV2 a Element Element 1 ja 4 iH H 75 Ohm Coaxial aes 5 eae Cable DXE RFS 2 a 1 o ANT a ANTI ANTI ANTI 75 Ohm Coaxial Cable 75 Ohm Coaxial Cable 75 Ohm Coaxial Cable 12 Vdc Power Feed 1 uses coax for ground return J Optional PPC IS 75FB 18 DC Pass Though Lightning DXE ARAV2 DXE ARAV2 A Protection Element Directional Control Element 3 gy tough Coaxial Cable l s DXE TVSU 1 12 Vde FCV 1 Ground Closure Se ON OWS GND to Station Ground use TA IMENE EUSA POS to Switch A NEG to Switch B See FVC 1 Manual for Matrix 75 Ohm Coaxial To Radio PTT Line Cable To Receiver Optional DXE RPA 1 HF Preamplifier RFS 2 Alternate Configuration Requires Internal Jumper Changes Uses optional DXE FVC 1 to control direction using feedline Uses Ground Closure Interface to control the FVC 1 DXE TVSU 1 used with station power 23 DXE RFS 2 and Active E
35. oax Connectors System Overview The DXE RFS 2 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 used with active receive elements this time delay phasing scheme provides the correct phase relationship across a wide frequency range and useful front to rear ratio F R response over octaves of bandwidth This system uses directionally optimized time delays to produce wider and deeper rear nulls Wide null areas and a narrow main lobe greatly reduce noise and undesirable signals The system is more reliable than a conventional transmitting four square system in receiving applications Most transmitting four squares use large exposed open frame relays which can become contaminated or corroded This system uses sealed relays contact size is optimized for receiving applications Features Advantages of the DXE RFS 2P Receive Four Square Antenna System over other receiving arrays include e Seamless stainless steel DXE RFS 2 enclosure for enhanced weather resistance e Reduced susceptibility to high angle signals compared to EWE Flag Pennant and K9AY antennas e Excellent directivity in a small space for better signal to noise ratio e Switching of four 90 degree spaced directions e Directivity over a very wide f
36. onal control voltages 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 For directional control through the feedline the DXE RFS 2 requires 12 Vdc 12 Vdc and 12 Vac The DXE FVC 1 Voltage Coupler can be used to supply these voltages Operational voltage is a nominal 12 Vdc which can be provided by station power if a 1A in line fuse is used In any alternate configuration do not use coax or other conductor for more than one simultaneous use Refer to Diagram 2 for connection details of one of several alternate configurations Installation The DXE RFS 2 Control Unit can be mounted to a galvanized pipe driven into the ground The DXE RFS 2 unit has been pre drilled to accommodate up to a 2 inch O D pipe using an appropriate clamp If pipe mounting is desired the optional DXE CAVS 1P V Bolt Saddle clamp for pipe from 3 4 to 1 3 4 inches O D is recommended or DXE CAVS 2P V Bolt Saddle Clamp for 1 to 2 O D 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 As noted in that manual the active elements should be installed as close to the
37. pensate for the low signal level Using a preamplifier when sufficient signal is already present may result in amplification of 26 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 The DXE RPA 1 preamplifier is automatically bypassed when power is removed Front to Rear Null Optimizing The DXE RFS 2 is factory adjusted to the correct settings for most coaxial cables In some cases the null depth may need to be adjusted to compensate for inaccurate delay line lengths To adjust the null depth tune to a strong steady signal off the back of the antenna s selected direction and adjust R4 and R8 for the deepest null weakest signal off the back Use Figure 5 to locate R4 and R8 near the center of the circuit board Operation When using the DXE RFS 3 SN 3 2 positions 5 though 8 on D a the CC 8 Control Box will phase the appropriate active vertical elements to give you excellent receiving capabilities The front to back signal to noise ratio of the active vertical elements in the four phase array allow you to not only enhance the desired received signal but also to decrease an unwanted receive signal by selecting a
38. requency range using DX Engineering s Active Receive Antennas e Requires less space than a Beverage antenna Active elements need only a minimal ground system e Using active elements system allows close proximity to transmit antennas using transmit recelve sequencer e Enhanced relay contact reliability Prerequisite This manual covers both the DXE RFS 2P stand alone unit and the DXE RFS TS2P system This manual will describe the DXE RFS TS2P total system package in detail The DXE RFS 2P includes the DXE RFS 2 Receive Four Square Switching Unit and the DXE CC 8 Control Console The DXE RFS 2 includes just the Receive Four Square Switching Unit The stand alone DXE RFS 2 unit must be connected with the appropriate power and switching voltages as defined in the Control amp Power Section of this document The DXE RFS 2 can also be used with passive elements The DXE RFS 2 is a sophisticated system that has critical control voltage and three delay line connections Failure to make quality feedline or delay line connections might result in an array that does not work or performs poorly Additional Parts Required Not Supplied with the DXE RFS TS2P Four Conductor Power and Control Cable for DXE RFS 2 Default Configuration 4 conductor cable 3 plus ground 22 gauge minimum Alternate configurations use a l or 2 conductor cable Economically priced DXE CW9 is a 9 conductor Shielded Control Wire which may be used Additional Parts R
39. rol Wire which may be used See Table 5 for the control matrix The optional DXE FVC 1 can be used to generate the required differential voltages using a 1 or 2 conductor cable Feedline shield can be used as the ground return e 2 bit BCD style control voltage using terminals A amp B See Table 4 This requires at least a 2 conductor cable Economically priced DXE CWS9 is a 9 conductor Shielded Control Wire which may be used The feedline shield can be used for the ground return provided it is grounded at the common power source If you choose to use the feedline to provide power to the DXE RFS 2 you will have to supply your own coupling circuit to insert the required 12 Vdc on the feedline Directional Control Using the Feedline If you use the feedline for directional control then you must provide power for the DXE RFS 2 using terminal C of the J12 connector Terminals A amp B are not used A single conductor cable is needed to power the DXE RFS 2 and active elements Station power nominal 12 Vdc can be used provided a 1A in line fuse is used Diagram 2 illustrates the coax being used for directional control and the use of station power Using the feedline for directional control requires differential voltages to switch directions Use Table 5 for the control matrix The optional DXE FVC 1 can be used to generate and couple the required differential voltages to the feedline or a single conductor cable The DXE FVC 1 can be controlled wi
40. se the coax for directional control then you cannot use the coax for power a separate cable must be used We recommend using the default configuration Default Jumper Configuration Settings Figure 5 shows the default jumper settings for the DXE RFS 2 For JMP1 amp JMP2 the center and top pins of both are shorted For JMP3 amp JMP4 the center and bottom pins of both are shorted JMP1 Selects Power Voltage Source Coax or J12 JMP2 Selects Direction Voltage Source Coax or J12 Shown set at Default Power and Directional Voltage from J12 JMP3 amp 4 Selects Directional Voltage Configuration Either Differential or BCD Both jumpers must be set the same Shown set for BCD Default ONLY through J12 Reverse RLY1 Figure 5 Jumper Locations and Default Settings 25 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 amp B of J12 for BCD style directional control JMP3 and JMP4 are used to configure the directional control voltages Both jumper blocks MUST be moved together as a pair With their upper two pins shorted differential voltage 1s enabled using Terminal C With the lower two pins shorted the BCD style interface is enabled using Terminals A
41. sed With 1500 watts output and a unity gain 0 dB antenna the closest active element can be 1 10 wavelength from the transmitting antenna at the lowest transmitting frequency Doubling the protection distance quadruples safe power levels See Table 1 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 1s required Table 1 indicates minimum safe distances from transmitting antennas with 0 dB 3 dB and 6 dB gain ERP using a 1500 watt transmitter Your actual measurements may vary according to location and proximity to various objects ity 0 dB Gain 3 dB Gain 2x 6 dB Gain 4x 160m 1 8 MHz 110 ft 220 ft 80m 3 5 MHz 112 ft 40m 7 0 MHz Table 1 Array 1500w ERP Safety Distance Topographical Considerations Flat land is best Erecting the receiving array on sloped land or steep hills may degrade performance To avoid pattern degradation antenna elements must have reasonably similar elevations It s recommended the ground height difference between any element in the array be less than 10 of the array diameter For example a 60 foot diameter array should be within six feet of level Every effort should be taken to make the elements symmetrical Elements should all be identical in constr
42. terns for an Optimized 40 meter Array Figure Site Selection Clear Distance Table 1 Array 1500 Watt ERP Safety Distance Table 2 Array Side Lengths Figure 2 Layout of the DXE RFS TS2P Four Square System Figure 3 Active Element L1MF Jumper Locations Table 3 Examples of DLY3 Required Length Figure 4 Diagonal Dimensions CC 8 and RFS Connectors DXE RFS TS2P Default Connection Diagram Using Factory Jumper Settings Diagram 2 Alternate Configuration Diagram 3 Alternate Configuration Table 4 BCD Directional Control Matrix Table 5 Differential Voltage Control Matrix Figure 5 Jumper Locations and Default Settings Operation Pattern Diagram OOANIDWMN BH W W 10 12 13 15 W 17 18 20 22 23 24 25 25 21 Introduction There are two packaged systems available DXE RFS 2P Receive Four Square Array Controller amp 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 The result is that noise and undesirable signals are greatly reduced for a superior front to rear ratio F R Better control of phase and currents provides a cleaner pattern than found on available transmit four square arrays The DXE RFS 2P is optimized to use DX Engineering s Active Vertical Antenna Package DXE ARAV2 4P The
43. th a CC 8 with a simple switch closure to ground scheme The DXE FVC 1 provides only the directional control voltages Study the configuration diagrams on the next pages and the Internal Jumper Settings on page 26 before making any changes to the default settings Diagram 2 shows the DXE FVC 1 used for directional control 21 Diagram 2 Alternate Configuration All Element feedlines delay lines and station feedlines must be 75 Ohm coaxial cable Element feedlines can be any length but must be equal Not drawn to scale DXE ARAV2 DXE ARAV2 8 7 ESS Element k Element IESS H E A 75 Ohm Coaxial TON Cable Cable DXE RFS 2 J ANT4 ANTS ANT ANTI 75 Ohm Coaxial Cable 75 Ohm Coaxial Cable 75 Ohm Coaxial 12 Vdc Power Feed Cable 1 uses coax for ground return or 2 Conductor Cable Use CC 8 Term C or Station Power Optional PPC IS 75FB 18 DC Pass Though Lightning Protection DXE ARAV2 Element DXE ARAV2 Element 2 Directional Control Sf Through Coaxial Cable DXE TVSU 1 FVC 1 to CC 8 Wiring GND to G Radio X r POS to A Neg to B 75 Ohm Coaxial Cable To Radio PTT Line DXE CC 8 as To Receiver Optional DXE RPA 1 HF Preamplifier RFS 2 Alternate Configuration Requires Internal Jumper Changes Uses Optional DXE FVC 1 to control direction using the feedline Uses DXE CC 8 BCD interface to control the FVC 1 may als
44. two products together offer great F R response over octaves of bandwidth DX Engineering s Active Receive Antenna System offers excellent receiving performance from 100 kHz to 30 MHz while using only a 102 in whip as the antenna element A unique design makes it vastly superior to traditional active antennas in both strong signal handling and feedline decoupling This results in significantly better weak signal reception due to lower spurious signal interference and reduced noise Finally this system offers greater reliability in receiving applications The DXE RFS 2P uses sealed relays sized for receiving applications with silver contacts to prevent oxidation and contamination Most transmitting four square switches use large open frame relays where the contacts are exposed to air which can lead to contamination Relays with brass contacts can oxidize leading to poor conductivity Advantages of the DXE RFS 2P Receive Four Square Antenna System over other small or medium size receiving arrays include e Reduced susceptibility to high angle signals compared to EWE Flag Pennant and K9AY antennas e Excellent directivity in a small space for better signal to noise ratio e Switchable in four 90 degree spaced directions e Djirectivity over a very wide frequency range using DX Engineering active receive elements DXE ARAV2 4P e Less physical space required than a Beverage antenna and active elements need only a minimal ground system e Enhanced re
45. uction and grounding and should be mounted above any standing water or snow line but as close to the ground as possible In general the system will not be affected by trees or foliage as long as the foliage does not contact the element Ideally in important receiving directions there should be a clear electrical path for at least 1 wavelength The site should allow a ground system to be evenly distributed around the antenna if one is required Site Selection in Relation to Noise Sources Because the array is directional across its corners use this example as a guide If you have a noise source and if your primary listening area is northeast locate the array northeast of the dominant noise source This ensures the array is looking away from the source of noise when beaming in the primary listening direction The second best location for the array 1s when the noise source 1s as far as possible from either side of the array If you look at patterns the ideal location for the array 1s 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 transmitting antennas and buildings are off the back or side of the receiving array 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
46. xtra cutting cartridge Snap N Seal connectors cannot be installed with normal crimping tools or pliers The DXE SNS CT1 is an essential tool for proper connector installation Note DO NOT use pliers or other tools to tighten the type F connectors they do not require high torque to make a good connection Damage to the various units may result and is not covered under warranty Example of Array Performance Dedicated receive antennas have better signal to noise ratios Directing the antenna away from noise sources or toward the desired signal path is the primary benefit Antenna gain is a secondary advantage As frequency increases the fixed array size becomes electrically larger in terms of wavelength The increased electrical spacing produces higher sensitivity average gain even though front to rear ratio only changes slightly On the low bands once the receiving system limits on external noise antenna directivity F R is the only thing that affects the signal to noise ratio An average Beverage antenna exhibits about 6 dB gain You would need two reversible Beverage systems to obtain 4 direction selectivity and you still would be limited to one or two bands The DXE RFS 2 occupies less space is much easier to install is less conspicuous and operates over a wider frequency range with similar or better performance A test array constructed at DX Engineering using the ARAV Active Elements and a side length of 35 feet showed excellent
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