The problem with traditional directives
Traditional multiband directives require traps, items ' interlaced ' etc to work on multiple bands. With these elements such antennas are a compromise considering the possible potential maximum antenna efficiency. The monoband beams like the ZX Yagis would be an alternative, but who can install three or more of these directives?
The idea: variable-length items
Fluidmotion, the manufacturer of SteppIR antennas has solved this problem im a very classy way. SteppIR varies the length of a retractable mechanical elements for metal bands meso. This allows you to adjust the antenna on any frequency in the range and optimum working conditions.
Construction of a SteppIR
Each element of a SteppIR antenna consists of lightweight fiberglass tubes, metallic element works in these tubes. That means, obviously, that the absolute size of the antenna do not change, the fiberglass tubes have a fixed length. The inner metal bands are a special copper beryllium (CuBe) which withstands millions of movements. The excellent electrical contacts are made with four self cleaning slider for each item. The metal band is perforated with a toothed wheel for the movement. The wheel is driven by a stepper motor precision, allowing accurate positioning.
Every single element is controlled by a cable with 4 conductors, or the 4-element SteppIR yagi requires 16 conductors. Down in the shack there's going to be a control box to adjust the antenna. For the amateur bands are available various values of presets for each band. Also a ' General ' mode allows adjustment of the antenna at any frequency (within the specific range). The antenna can be memorizzzati setups for later recall, other functions then allows the quick reversal of directional pattern ' or bidirectional mode where the gain is going to be so distributed in two directions. An optional interface for your CAT allows direct control from transceivers: the antenna will be adjusted continuously when you change the operating frequency.
Optional radiator 30/0.02 MI
Replaces the standard radiator and allows to work under 40 m. available in two versions: one like antenna and an option to acquire as part of an existing antenna.
Technical data and comparison
Dipol2 Yagi3 YagiDB Yagi4 YagiMonstIR 4 Element Element Element Element-18DB-18E frequency Range (continued)5413.8-5413.8-5413.8-13.8-546.9-546.8-546.8-54MHzMax. power3333333kWWeight4.513 .619, 0349841.245.3 kgantenna surface0.170 .370 .570 .902, 220.91.1 m2Max windspeed~ 160 160 160 160 160 ~ ~ ~ ~ ~ ~ 160 160 km/hlongest Element.5011 .8811 10.9710 .9710 .9710 .9721, 88 mturning radius5.485 .536 .007 .3512 .506 .206, 50 mboom length-1.444 .879 .7510 .465 .805, 80 &boom diameter-4.54 3 & 5, 76, .54 .5 755cmMax Mast diameter 53535353535353mm 481216161616Conduttoricontrol CableBalun includedNo (optional) SiSiSsiSsiSiSi