Balun Designs offers this unique balun using a three inch double height core. This larger size provides the necessary increase in inductance for enhanced performance on the low bands while maintaining the same wide bandwidth up through 54MHz. Jerry Sevick's research showed that, when used with a balanced antenna, this balun provides current balance normally found only in a current winding. This design can be used with doublets, extended Zepps, large skyloops and is a good replacement balun for Super Loops.
In addition, the Thermaleze wire/Teflon tube windings on a large iron powder core allow the balun to handle large swings in impedance and high temperatures with ease. All of these features make the unit very unique and rugged while literally providing the best of both a current and a voltage winding design when used with a balanced antenna.
If you use ladder line or twin lead for your antenna, this balun can be installed remotely allowing you to run a short length of coax into your tuner or transceiver. This type of installation will keep stray RF (common to ladder line) out of your shack while retaining the low loss efficiency of ladder line for your antenna. The model 4124x has no enclosure and makes a great balun for homebrew tuners or tuners that do not incorporate a 4:1 balun in their design.
Jerry Sevick (W2FMI) specifically researched and designed this balun to provide a very constant 50 ohm input impedance on the lower frequencies where most baluns can drop by 20-40%. Please review the impedance curves in the graph below to better understand the efficiency and response of this balun.
The Mod III is especially effective on the low bands and can provide enhanced matching capability where other baluns fall short.
Click to Enlarge
- Large 3" DOUBLE HEIGHT iron powder toroid provides excellent low frequency impedance matching. Toroid is also coated with epoxy paint for added durablity.
- The large toroid provides better inductive reactance for excellent low frequency response. This makes the balun very efficient on 160, 80 & 40 meters while maintaining excellent performance for higher frequency multiband designs. Input impedance remains basically flat across the full HF spectrum and well past 30 Mhz. (click on graph above to view comparison). Competing designs can very as much as 40% especially from 1-5 Mhz.
- Bifilar (2) winding of Superior Essex Heavy build polyamideimide "Allex 240 Winding Wire" inside Teflon tubes. Minimum of 10,000v breakdown voltage.
- SO-239 connector is silver plated with teflon insulation.
- All hardware is Stainless Steel.
- N connector and Alternate mounting options are available in Accessories.
- Because of the high efficiency and size, it will not saturate like the smaller toroids or small stacked baluns used in many tuners.
- Iron powder core is very tolerant of higher temperatures.
- Balun is installed in 4" X 4" X 2" NEMA Box which makes an excellent outdoor weatherproof enclosure and can be easily mounted remotely.
This balun will handle continuous power of 5kw and tolerate high SWR for extended periods.
It will not heat up at rated power, using extended duty cycles or stressing load conditions.
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