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BevFlex-4X Low Noise Receiving Antenna
Installation Manual
Rev 2.23 November 2019
Unified Microsystems
PO Box 133
Slinger, WI 53086
https://www.unifiedmicro.com/bevflex4x.html
BevFlex-4X System Description and Performance Guidelines
The Unified Microsystems BevFlex-4X is an upgraded version of the BevPro-1 and BevFlex-4 Beverage antenna systems
now in use worldwide for weak signal, low noise reception. This product retains ALL of the features of the original
BevPro/BevFlex series while adding the flexibility to accommodate a total of five different antenna systems where the
installation of a classic, above ground, Beverage is impractical due to space constraints. A key feature of the BevFlex-4X
system is the ability to install ANY of these four antennas using the SAME components included with the BevFlex-4X kit.
Descriptions for each antenna configuration follow.
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Summary of Contents for Unified Microsystems BevFlex-4X
- Page 1 Beverage is impractical due to space constraints. A key feature of the BevFlex-4X system is the ability to install ANY of these four antennas using the SAME components included with the BevFlex-4X kit. Descriptions for each antenna configuration follow.
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Page 2: Getting Started
1. Getting Started The BevFlex-4X is a versatile system that can be used to build five types of low band, low noise, receive only antennas. This manual has a separate section for each type. You should read the first part, Classic Beverage System, first regardless of Page-2 BevFlex-4X Installation Manual Rev 2.23 November 2019... - Page 3 The following chart in Table-1 can be used as a general guideline to aid in typical installation decisions. The bulk of field experience with the BevFlex-4X design has been with systems ranging from 270 ft. to 800 ft. in length, but testing with antennas as short as 150 ft.
- Page 4 Antenna Antenna Length Overall Performance Vs. Band Relative Directivity 160m 160m 100 ft. 150 ft. 250 ft. 350 ft. 450 ft. 550 ft. 750 ft. 950 ft. E=Excellent, G=Good, F=Fair, P=Poor, NIL=Insignificant Page-4 BevFlex-4X Installation Manual Rev 2.23 November 2019...
- Page 5 Figure-2 Typical Antenna Pattern for a 500 ft. BevFlex-4X Antenna @ 8 ft. above ground (4 MHz) 3 dB Beam-width: 59.6° Front to Back Ratio: 20.6 dB Elevation Angle 29.0 deg. Outer Ring -4.4 dB ref. NEC-4 EZNEC Pro/4 Figure-3 Typical Antenna Pattern for a 500 ft. BevFlex-4X Antenna @ 8 ft. above ground (1.9 MHz) 3 dB Beam-width: 86.2°...
- Page 6 All received signal levels will be lower on the BevFlex-4X than receiving on your transmit antenna, but you will now be able to hear signals that were buried in the noise on your transmit antenna.
- Page 7 GENERAL INSTALLATION INSTRUCTIONS In addition to the BevFlex-4X kit, you will need to have the following items as part of your Beverage antenna installation: RG-6, 75 Ohm, CATV, coaxial cable: Sufficient RG-6 coaxial cable for use as the actual antenna element, plus (2) separate, feed lines from the feed point anywhere along the antenna element to your receiver location.
- Page 8 BEVERAGE ANTENNA INSTALLATION: 1. Determine the location for your BevFlex-4X antenna and install a 4 ft. ground rod at one end. (Scrap copper water pipe can also be used in soft ground). Try to locate the BevFlex-4X antenna element as far as possible from your transmitting antenna and its counterpoise radials.
- Page 9 7. The feed point for the BevFlex-4X can be located at any point along the entire length of the coaxial cable antenna element. If you are feeding it from either end, simply connect the feed box from the kit directly to the end box with a short RG-6 coaxial jumper or an “F”...
- Page 10 Notes of caution: As stated at the beginning of this document, the BevFlex-4X is a RECEIVE ONLY antenna system and must be protected from accidental application of RF power to the Rx output “F” connector or any of the other system RF connectors.
- Page 11 If this occurs, you can replace this fuse with an identical 50 ma fuse available from Unified Microsystems (Bell P/N MRF 50, available from DigiKey and Mouser ) or insert a small jumper wire or 10 ohm resistor across the pads G2.
- Page 12 Many of these external T/R relays do not have enough isolation and fast enough switching time to protect the BevFlex-4X. If your transceiver has an adjustment to delay RF output for a time interval after the PTT keying is activated, this delay should be set to...
- Page 13 You will notice that all received signal levels will generally be more than 10dB lower than on your transmit antenna, but the signal to noise ratio on the BevFlex-4X will typically be much better than on your transmit antenna for signals coming from the favored direction of the BevFlex-4X antenna.
- Page 14 3. Beverage-On-Ground (“BOG”) or Beverage-In-Sod (“BIS”) The BOG antenna that is sometimes referred to as a “snake” antenna is nothing more than a BevFlex-4X installed on or just under the ground surface. While it might seem counterintuitive to have your receive antenna at or slightly (less than 1 inch) below ground level, it does work and has some interesting feature differences when compared to an above ground Beverage installation.
- Page 15 Figure-11 Typical Antenna Pattern for a 175 ft. BevFlex-4X Beverage on Ground Antenna (BOG @ 1.9 MHz) 3 dB Beam-width: 98.6° Front to Back Ratio: 15.1 dB Elevation Angle 35.0 deg. Outer Ring -21.6 dB ref. NEC-4 EZNEC Pro/4 Figure-12 Beverage-On-Ground Antenna Block Diagram...
- Page 16 The inverted EWE antenna was first described by Floyd Koontz, WA2WVL, and documented in the February 1995 edition of QST. It is, by far, the smallest of the four receiving antenna variations possible with the BevFlex-4X system. The EWE consists of a single wire element in an upside down “U” configuration, as shown below. The EWE is not a traveling wave antenna like the Beverage and BOG, but is really a phased array of two, short, vertical, antennas that are top coupled by the horizontal wire.
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Page 17: Control Unit
Any length, do not need Ham Shack to be the same length Note: Feed line connections FWD IN REV IN Receiver are reversed for EWE, Flag, Coax and VE3DO configurations. Control Unit Page-17 BevFlex-4X Installation Manual Rev 2.23 November 2019... - Page 18 Figure-15 Typical Antenna Pattern for a 34 ft. x 16 ft. Flag @ 10 ft. (1.9 MHz) 3 dB Beam-width: 150.8° Front to Back Ratio: 33.2 dB Elevation Angle 31.0 deg. Outer Ring -29.7 dB ref. NEC-4 EZNEC Pro/4 Figure-16 below shows a typical Flag antenna installation. Page-18 BevFlex-4X Installation Manual Rev 2.23 November 2019...
- Page 19 Note that the coaxial feed-line connections to the switching control unit are reversed from the Beverage connections when the BevFlex-4X is configured as a Flag or EWE antenna system. The major advantage of the Flag antenna is retention of reasonable low frequency, low noise performance with a much smaller real estate requirement than either the Beverage or BOG.
- Page 20 VE3DO antenna. Figure-17 Typical Antenna Pattern for a VE3DO (1.825 MHz) 3 dB Beam-width: 144.6° Front to Back Ratio: 20.35 dB Elevation Angle 33.0 deg. Outer Ring -29.6 dB ref. NEC-4 EZNEC Pro/4 Page-20 BevFlex-4X Installation Manual Rev 2.23 November 2019...
- Page 21 The different antennas supported have different impedances. The Terminator Units have different taps and terminals to account for the different impedances. Table-3 summarizes the connections and internal jumpers for the antenna types supported. Page-21 BevFlex-4X Installation Manual Rev 2.23 November 2019...
- Page 22 Terminator Internal Jumper Settings The five antenna types supported with the BevFlex-4X have different impedances that must be matched to 75Ω RG-6 coax. That is the job of the terminator units. Jumpers inside the terminator units select the proper taps on the impedance matching transformer.
- Page 23 9. Troubleshooting the BevFlex-4X System To fully test all the components of the BevFlex-4X system, you will need an RF antenna analyzer in addition to an Ohmmeter. The RF analyzer is required because most of the connectors on the BevFlex-4X system components are terminated in transformers, which will measure as very low resistance readings on an Ohmmeter.
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Page 24: Warranty And Support Information
Warranty and Support Information The BevFlex-4X is warranted for parts and workmanship for a period of one year from the time of purchase. Unified Microsystems will repair or replace failed units at its discretion. Physical or lightning damage is not covered under warranty. - Page 25 VE3DO antenna. No other product on the market offers the ability to create all five configurations and CHANGE them if and when your installation situation changes. Although the classic Beverage antenna configuration should yield the best results, the BevFlex-4X kit allows you to experiment and find what works best for you within the limitations of your location.
- Page 26 The BevFlex-4X has the unique ability to be fed from any point along its entire length. Plus, it utilizes inexpensive RG-6 coax cable vs. more expensive ladder line that is required for other reversible direction systems. 6. What bands does this antenna cover? The BevFlex-4X antenna is capable of receiving all HF bands, as well as the AM and LW broadcast bands.
- Page 27 17. Will I need to use an external preamp with this antenna? Generally, no external pre-amplifier is required or desired as signal levels from the BevFlex-4X are well above the noise floor of your receiver on frequencies below 10 MHz. Received signals from the BevFlex-4X will almost always be LOWER in “S”...
- Page 28 20. What is the minimum distance that I need to maintain between my transmit antenna and the closest point of the Beverage? The further, the better, as noise can be re-radiated from the transmit antenna into the BevFlex-4X. Typically, 50 ft. spacing is sufficient. It is important to locate the BevFlex-4X away from vertical transmit antenna systems, including the ground or elevated radial wires.
- Page 29 (4) different directions? Yes, you can install multiple BevFlex-4X antennas that cross each other as long as the antenna wires cross at close to a 90 degree angle to each other and are separated by at least 12 inches. This spacing and orientation will minimize the coupling and interaction between the two antennas.
- Page 30 RF impedances of the parts of the system you are troubleshooting. 34. What can an RF antenna analyzer tell me about the operation of my BevFlex-4X? If all the connections are intact, and the correct impedance taps are selected on the end termination units, you should see a VSWR of typically less than 2:1 (referenced to 50 Ohms) across a frequency band from 1.8MHz to 10.0...
- Page 31 There is no requirement that all of the BevFlex-4X antenna configurations be Beverage or any other type of bi- directional antenna. Beverage antennas can be switched with BOG, EWE, FLAG, or VE3DO antennas as long as the correct antenna impedance taps are selected on the end termination units for each of the antennas.
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