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BevFlex-4X Installation Manual Rev 2.23 November 2019
We have experience with a 270 ft. above ground, Beverage antenna and were pleasantly surprised by how well it
worked even on 160m. We also have experience with a175 ft. BOG on rocky soil and were impressed
by how well
it worked on 160m and 80m. This short BOG was able to achieve a 20dB front to back ratio on an AM broadcast
station 40 mi away on 1600 KHz. If you want a high front to back ratio on 160m with a short antenna, we would
recommend the BOG configuration. We were frequently able to receive DX stations on either of these antennas
that could not be copied on the transmitting antenna. Even with the BOG configuration, you will generally not
need a pre-amplifier on 160m and 80m since the atmospheric noise level is still higher than the noise figure of a
modern receiver.
26. I have less than 50 ft. available. Can I still build an effective, receiving antenna with the BevFlex-4X?
Yes, we have experience with EWE and FLAG antenna configurations as short as 25 ft. Although the gain is lower
than a Beverage or BOG antenna, the EWE or FLAG antennas can still provide a low noise receiving capability with
good front to back directivity. We have experience working stations than could not be heard on a dipole transmitting
antenna using a 25 ft. EWE antenna for receiving. The VE3DO is another, slightly larger (40 ft.), antenna for
restricted space applications.
27. Can I have two BevFlex-4X antennas installed at right angles to each other to get optimum reception
from (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.
28.
Can I feed more than one receiver from my BevFlex-4X antenna system?
Yes, you can use any standard 50 or 75 Ohm, isolated port, signal splitter that works down to your frequency band of
interest to feed multiple receivers. The splitter would normally be placed after the direction switching unit. You can
also split the forward and reverse feedlines from the antenna coupling unit into multiple feeds ahead of the
directional switching unit. Switching ahead of the BevFlex-4X Switch Unit will require separate termination of
unselected lines with a 75 Ohm resistor.
29. How long can the feedline cables be from my shack to the Feed Unit?
Insertion loss measurements of coaxial cable with either solid copper or copper plated steel center conductors
confirm that the losses of RG-6 coaxial cable are very low at HF frequencies. Feed cables up to 1000 feet should
not be an issue. Dual RG-
6 “Siamese” pair type cable is very convenient for the feedlines from the antenna feed-
point to the operating position. The feedline cables do not have to be equal in length.
30. Do the A/B feedline cable lengths need to be matched in length?
No, the cables do not have to be length or phase matched for any of the four configurations to work properly.
31. Why is coaxial cable better than open wire, window/ladder line,
or “twisted pair wire” for the antenna?
The use of well shielded RG-6 coaxial cable provides better isolation between the common mode received signal on
the outer surface of the shield and the differential mode signal inside the coaxial transmission line. The characteristic
impedance (Zo) of the coaxial transmission line is not affected by the external environment as much as the (Zo) of
unshielded, parallel conductor transmission lines. Light weight, RG-6, coaxial cable is generally less expensive,
easier to hang, and maintain than window/ladder line.
