The DX Shop are distributors for Balun Designs.
This is a balun originally designed by Guanella and subsequently improved by Dr. Jerry Sevick (W2FMI). By utilizing Thermaleze wire inserted in teflon tubes, Dr. Sevick was able to substantially increase the breakdown voltage between both conductors and windings while improving the overall input impedance.
Long way of saying this is a Current balun that will handle high power over 1MHz to 54mhz. It’s a good choice to transform ladder line fed multiband doublets and cobra designs to coax, and to build off center fed dipoles around.
- Custom mix toroid provides broadband coverage. Toroid is coated with epoxy paint for extra durability.
- The design has excellent low frequency response and very efficient (98-99%). Input impedance remains essentially flat across this frequency spectrum. Competing designs can very as much as 40%, especially at lower frequencies.
- 2 separate bifilar windings of 14 gauge Superior Essex Heavy build polyamide Allex 240 Winding Wire. This is NOT the enamelled type (Formvar) used by my less expensive competitors. It is coated with a polyimide covering rated at a minimum of 2000v breakdown voltage. The windings are then inserted into teflon tubes which increases the total breakdown to 10,000 volts.
- Typical insertion loss is < 0.2db
- SO-239 connectors are silver plated with teflon insulation. All hardware is Stainless Steel. Eyebolts and studs are 1/4″
- Because of the high efficiency, this balun will not heat up or saturate like the typical cheap current baluns using ferrite rods, beads or open air wound coax.
- The balun is installed in a weatherproof 4″ X 4″ X 2″ NEMA Box which is an ideal enclosure for those who want to mount the balun remotely.