DX Engineering TWIG QRP 4:1 Current Baluns are designed to be used as the feedpoint of a very low power (QRP) Off Center Fed dipole (OCF) antenna. Ideal for use during outdoor adventures such as POTA® or SOTA®, or any portable operation. The TWIG-4-1C incorporates a 4:1 transformer to convert the OCF antenna impedance of 200-ohms to the desired 50-ohms to match the coaxial cable feedline. It also has a 1:1 feedline choke, to prevent current imbalance, detuning, and to help prevent the addition of unwanted noise. The connector is a BNC female and mates with the recommended coax and most low power (QRP) transceivers. When properly installed and the element wire is properly tuned, you should not need an external tuner. This minimizes the need to carry unnecessary equipment during portable operations while delivering higher signal efficiency and enabling instant band changes.

The antenna shown in the user manual was designed and tested using the optional 24 AWG wire such as CEW-VIZ24-YEL100 stranded copper, PVC insulated, high visibility yellow antenna wire. It is recommended that the coax cable should be at least 25 to 35 feet in length. The antenna can be installed in different configurations of wire lengths for various band selections. For example, a very common TWIG QRP OCF for 40, 20, 15 and 10 meters has one 57 foot dipole wire and the other wire is 12 feet in length. See the chart in the Instruction Manual linked below for details. This is a low power (QRP) antenna system balun which handles only 25 Watts on SSB, 10 Watts on CW and 5 Watts on digital modes when antenna SWR less than 2:1, without the use of an antenna tuner.