Beverage antennas - Beverage receiving antennas
Beverage antenna transformers
One wire configuration notes
- Use separate ground rods, as sharing can cause signal coupling through the connection.
- The copper coating on steel ground rods disappears with time. Recommend the use of thick wall copper pipe, available in most hardware stores.
- Break away ties/fastenings improve wire survival from falling limbs, and trees. 40 to 50 pound monofilament fish line works well.
- Keep the Beverage ends away from towers that can re-radiate signals, even if they are not used as transmit verticals.
- Woods, trees, and vegetation, represent only minimal signal loss reported over many years. One wooded area, low to the ground Beverage at my QTH is also under the snow much of the winter, and works fine.
- Maintain a reasonable constant height above ground except at the ends that may be tapered to ground level. Follow the general contour of the earth, but not every small dip or bump.
- Beverage antennas "want to work". For best results run a straight line. If a straight run can not be maintained, good results can be obtained with less than perfect.
- If the Beverage is being used as a single direction terminated antenna, the termination resistance
is controlled more by ground conductivity, than wire height. A poor conductivity earth termination would typically
be 350 ohms or lower. A more conductive earth termination would typically be 450 ohms or higher.
- When choosing a termination resistance, avoid the one that gives the minimum VSWR on the
band of interest, rather choose the resistance that gives the lowest VSWR over a wide frequency range with a slow
increase at the highest frequency end. You may end up with a 1.8:1 VSWR, but you will have found the
characteristic impedance of the wire resulting in the best antenna front to back ratio. (The 1.8:1 VSWR would be most likely from a matching transformer to antenna impedance difference)
- Beverage antennas require the bending of radio waves to work. Lower frequency radio waves bend around mountains, into valleys, and have deeper earth penetration. Poor conductivity earth helps provide earth penetration, and the necessary bending. (Often called tilt angle)
- It has been said "A Beverage antenna should be run across a desert with a swamp at each end" A Beverage will not work well over highly conductive ground or sea water. (The swamp at each end was for your ground rod.)
- If you are near the sea, running the Beverage antenna along the beach will result in a antenna that will not work well. You could arrange your Beverage so it starts or ends up near the waters edge to get a good ground, and run away from the coast line at 90 degrees, to receive those low angle signals that tend to follow sea water. For other directions avoid the ocean's edge.
- If sea water extends under the earths surface inland, treat this as a high conductive area.
- When purchasing a Beverage antenna transformer, recommend a 450 ohm transformer for a more conductive locations, and a 330/350 ohm transformer for a low conductivity locations. Closer matching to the transformer will increase the signal to your radio, but will not change the antenna pattern.
- Beverage antennas are low impedance, low Q devices, and do not couple well. Beverage runs can cross each other if a few feet of clearance is allowed.
- Radial fields radiate energy from the connected vertical. Avoid running a receive antenna, or receive coax across one. (Raised radials radiate more signal energy than in ground radials.)
- Take care not to transmit into a Beverage antenna with standard transformers. If transmit is desired, an
antenna tuner could be used in place of the Beverage transformer. A much higher wattage termination resistor would be needed.
(Beverage antennas have negative gains)
- For those not wanting to go in to a switchable Beverage system. It is possible to recieve in the direction that wires can not be run. A KB-2 transformer can be connected to two wires running away from the direction wanted will provide that reverse directivity.
(One of the two wires grounded at the far end, a ground rod at the KB-2 box, a termination resistor on the forward SO-239 connector, and a coax from the reverse SO-239 KB-2 connector to your radio shack is all that is needed).
This method is not new. Harold Beverage used it at 1XAO the Belfast, Maine long wave, radio relay station in 1923.
- There have problems reported using heat shrink on termination resistors, and multiple reports saying no protective covering is necessary.
Two wire, two direction Beverage notes