Balun Designsis now offering a low power alternative for those who want to use an End Fed Half Wave for portable or temporary installations. Built with the same craftsmanship as all our other units, this new model provides excellent flexibility and portability for events such as Field Day, POTA, SOTA etc. With this particular unit, the coax shield of the feedline acts as the counterpoise for the antenna so the feedline used should be a minimum of about 0.05λ of the lowest band being used. As an example, this calculates to ≈ 4.2 m or ≈14 ft for an 80m EFHW.
When used at full power rating of 200 watts, the antenna must have a low SWR on the band selected and be used on a 50% duty cycle. Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1 with NO tuner in use. There are numerous configurations available online that will accomplish this on multiple bands (Google search "end fed half wave antennas"). If the transformer is used with an external tuner in conjunction with a single wire antenna typically 130-135 feet in length, power should be reduced on those bands that show an SWR above 1.6 to 2:5 without the tuner. A level of 100-150 watts is the maximum with a further reduction on any band measuring above 3:1.
The enclosure for our low power units is small, lightweight and portable, but not intended for long term 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 is not covered under our warranty.
|Core Material|| Custom mix low permeability ferrite by Fair Rite Products for maximum bandwidth.
Core is coated and sealed for long term durability.
|Winding Type|| Single core with winding configured as 49:1 auto transformer
Downward impedance transformation by factor of 49.
|Winding Material|| 16 gauge Superior Essex Heavy build polyamideimide Allex 240 Winding Wire.
|Power Rating||3 to 31 MHz - up to 200 watts (50% duty cycle)|
|Useable Frequency||3 to 31 MHz|
|Connectors|| SO-239 connectors are Nickle plated with Teflon insulation.
Stud is #8 hardware.
Alternate connectors and Mounting Options are available in the Accessories section.
|Hardware||All Stainless Steel|
| Enclosure Type
||Polycarbonate (ABS) box with bottom plate that fits flush with the case.
Plate is an exceptional fit that can be easily weatherproofed if desired.
|Dimensions||Very compact and lightweight 3x2x1.5 inch -Link to dimensional drawing|