Balun Designs is now offering a new line of baluns built just for the QRP operator. Each balun is still built with the same level of attention to detail and quality just oriented toward those who enjoy the thrill of using low power. Additional Photos: Windings, Size Reference This model is the popular Isolation/choke balun that is perfect for feedline isolation, noise reduction and RFI management. All of my baluns are hand made, hand wound one at a time and based on tested and proven designs. They may look simple but the right components are expensive and hard to find even before attempting to wind one. This is a current balun and has the widest operating frequency range, lowest core stress and provides the best overall balance of any balun for given cost, size, and weight. This balun is the best type to balance currents on each side of a 1/2 wave dipole or the driven element of a yagi while providing the perfect transition from a balanced antenna to unbalanced coax feedline. Installing this balun will not affect antenna matching unless the feedline is acting as part of the antenna. This is, of course, not a desirable situation and installing this balun will correct the problem if one exists with the antenna. In beam installations, using a 1:1 balun in series with the antenna’s feed system can substantially improve the antenna’s front-to-back and front-to-side ratios. It does this by providing the antenna's driven elements with balanced current at the feedpoint and by preventing the feedline from acting as part of the antenna. It is a seldom appreciated fact that feedlines, which are not adequately decoupled, can act as efficient vertical antennas degrading an otherwise excellent radiation pattern. The addition of a 1:1 balun can significantly reduce feedline radiation and dramatically decrease RFI and TVI. Beam antennas especially benefit from improved balanced drive and superior feedline isolation, but even simple dipoles benefit from properly selected and installed 1:1 current baluns. Receiver noise may also be reduced by eliminating signal pickup by the coax shield. Design features: Utilizes specifications of Jerry Sevick, W2FMI, the authority on baluns. This is his Guanella current balun design which he modified to provide higher efficiency. By utilizing a new toroid mix with low permeability, the bandwidth of his design has been increased. Toroid is coated with epoxy paint for added durablity. This Isolation balun has significantly higher common-mode impedance and larger effective core area than other similar designs. It is much more effective than types with ferrite beads, ferrite bars or wound air-core coax. Windings are 16 gauge Thermaleze wire rated at 1200v breakdown between the two winds. Typical insertion loss is less than 0.2 dB Power handling upto 250 watts continuous SO-239 connectors are silver plated with teflon insulation. Alternate connectors are also available in the Accessories section. Very high efficiency. Will not heat up or saturate like many of the typical cheap current baluns. Balun is built installed in a very compact 3 X 2 X 1.5 inch polycarbonate with a bottom plate that is an excellent fit. Weatherproofing can be easily attained.  Note: Color may be light grey or black   This balun will handle continuous power of 250 watts and tolerate high SWR for extended periods. It will not heat up under extended duty cycles or stressing load conditions. Additional Photos: Windings, Size Reference   **CAUTION** By design, QRP baluns are constructed to be lightweight and portable and are not intended for longterm or permanent outdoor use. If used in a permanent outdoor installation, additional attention must be given to weatherproofing and strain relief. Damage caused by such use will not be covered under our lifetime warranty.

Balun Designs