RX antenna - Bi-directional 2-wire beverage TWO coax output

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rev.1 6/2016 by Jan OK2ZAW

Assembled KIT (Edit)

The drill drawing(Edit)

Paste the drawing on the box and fix it with some tape.

Drill 3 or 3,2mm holes for connector.

Drill 4mm holes for antenna screws.

Bend the screw heads into box

- use 6mm drill and do it slowly by hand

- drill 16mm hole for connector

Insert the screws(Edit)

Insert stainless screws 4mm with

Mount the RF connector(Edit)

insert connector and use steinless M3x8 and one M3x10 with grounding eye.

Drill the hole for the PCB holder(Edit)

- mark the hole center by the PCB

- drill the 3 to 3,2mm hole.

Feeder PCB assembling(Edit)

VERY IMPORTANT !(Edit)

- LOAD unused coax line with right impedance (50 or 75 Ohm) !!! Never use it unloaded!

KIT parts example(Edit)

Assembling(Edit)

TRANSFORMERS winding - very important thing!(Edit)

  • example of some transformers

- example of 3,5 turns

- 2 and 6 turns

- 2 x 3,5 turns on secondar and 2 turns on primar

- example for terminator 9 turns and 6 turns, where 9 is two times 4,5 turns

- example two time 5 turns and 3

Connect PCB to the screws(Edit)

- check the lable on the box and connect wires. There must A, B and GND connected to right screws on the box.

Common-mode coax choke(Edit)

- choke measurements

Wind the coax(Edit)

- Wind the coax as is on the picture, there should be 7 or 8 turns.

- fix it by one binder and use second one to fix choke to the PCB

Solder the coax (Edit)

The Terminator(Edit)

- Do right turns calculation or use table values.

Drill the holes(Edit)

Ready to use. Go to the field! :-)(Edit)

Example of beverage construction(Edit)

The beverage is a long wire antenna installed very close to the ground. The antenna should be longer than 1 wavelength and installed at a height of less than 0,05 wavelength above ground. The beverage is usually terminated in a resistance at the end (opposite the feedpoint).

Beverage antennas provide one of the least expensive and most reliable ways to improve DX capabilities on the low frequencies.

With careful attention to design and construction, a single beverage antenna can be made to cover two directions with excellent performance over a very wide frequency range.

The transformer at the end of the beverage is designed to match impedance of the antenna.

A two-wire bi-directional beverage requires the antenna element to operate a balanced transmission line, as well as a conventional long wire antenna. The parallel wire line used to construct the antenna must be excited under near-perfect balanced transmission line conditions.

This is why each of the parallel transmission line wires must be parallel to the ground. A line should not be constructed in a vertical fashion, using single support poles with one wire under the other. The closer the wire spacing of the line, the lower the impedance of the line, and the less critical installation-related unbalances become. The higher you install the line above ground, the less unbalance any unequal coupling to earth creates.

Source: W8JI, ON4UN

  • Example of the construction details. Two wires with the distance of 10 to 13 cm.

- PC5M 4 direction design - source PC5M

- ZL3IX Bi-dir beverage notes


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