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BevFlex-4X Installation Manual Rev 2.23 November 2019
which antenna type you plan to install. That section covers the basic component operation and installation instructions that
apply to all antenna configurations.
2.
Classic Beverage system
The Beverage receiving antenna was invented by Harold H. Beverage in 1921 and is a proven performer for receiving weak
DX signals in the presence of atmospheric and man-made noise. The Beverage antenna is not suitable for transmitting since
its overall relative gain is typically 10dB or more lower than a dipole antenna. You may ask why a receiving antenna with
such low overall gain is useful as a receiving antenna. The answer lies in the fact that the noise levels on the long wave,
medium wave, and lower HF bands are far above the sensitivity of modern receivers. While the overall gain of the Beverage
receiving antenna is much lower than most transmit/receive antennas, the signal to noise ratio of signals received in the
favored direction of the Beverage antenna will be typically significantly higher than on the main, transmit/receive antenna.
The physics behind the antenna design itself are well documented and well understood. You will find many reference articles
on-line that fully describe a wide range of creative implementations of Beverage antenna designs ranging from simple to
complex.
The performance of the BevFlex-4X Beverage antenna system will be as good as or better than conventional Beverage
system installations of the same height and length. The BevFlex-4X design uses RG-6 coaxial cable that is inherently easier
to install and more stable than reversible systems employing “open wire”, “window/ladder line“, or “twisted pair wire”. The
BevFlex-4X provides increased performance and ease of adjustment in real world installations. The basic Beverage
antenna consists of a wire antenna element, a terminating resistance at the far end, and a feed system to bring the signal
back to the receiver. Reversible Beverage systems provide the additional feature of switching the termination and feed ends
of the antenna system to provide bi-directional performance.
The BevFlex-4X uses a common mode, receiving antenna, wire element, consisting of the outer shield of the RG-6 coaxial
cable that extends to each end point of the antenna. The outer shield of the coaxial cable is continuously connected
regardless of where the unique feed system is placed along the entire length of the antenna. The terminating resistances to
correctly match the impedance (Zo) of the antenna at each end point are replaced with precision reflection components to
couple the signals from each end as differential signals inside the coax between the center conductor and shield of the
coaxial cable. The center conductor of the coaxial cable can be separated at any point along the entire antenna element
length where these differential signals from each end are then brought to the receiver location via the feed point coupling unit
to two individual, coaxial feed cables.
Regardless of where the feed point is installed along the antenna, the entire length of
the antenna is always utilized.
The coaxial cable used as the antenna wire simultaneously operates as a common mode
antenna and as a differential mode transmission line to bring the signal back from the one end of the antenna while also
providing the correct terminating resistance to the other end of the antenna. At the receive location, a switching and
impedance matching system is employed to reflect the correct terminating resistance value back to each end of the antenna
via the inner conductor of the coaxial cable. While all this sounds simple, it has taken years of prototyping and testing by
W8GNM, WC4X, and W9XT with precision test equipment to get the various components designed and developed to the
point where a product can be manufactured in quantity to get predictable results.
The exact performance of any given beverage antenna system is dependent on many variables, such as ground conductivity
and mounting height above ground, but the most common variable under the control of the operator is the overall antenna
length. 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. in length has yielded encouraging results, especially for the 40 meters to 15 meter bands.
Figure-2 shows a typical antenna pattern for a 500 ft. antenna at 4 MHz, and Figure-3 shows a typical antenna pattern for a
500 ft. antenna at 1.9 MHz.
Table-1 BevFlex-4X
Performance Guidelines
Above Ground Beverage
