The XP-507 beam is an intermediate sized beam designed to replace conventional 3- and 4-element antennas. Although the boom length is a modest 4.4 metres, superb performance is obtained through the TOTAL elimination of L/C traps. Former trapped-antenna owners immediately notice increased signal reports, broader gain and SWR bandwidths, and f/b ratios that are good across the entire band – not just over one small sector.
The XP507 covers 6,10, 12, 15, 17, 20 ,30, 40 meters bands.
To maintain high performance, the DJ2UT antenna is fed with a model UT-2000 balun. This is an air-core device made from high-voltage, Teflon dialectric coaxial cable. With no ferrite core to saturate, this balun will handle 2 kW output without heating and the beam is rated above maximum legal power – regardless of mode or band.
The XP507 antenna is built to very high standards of strength. Aircraft-quality aluminum tubing is used throughout, and all hardware is made of stainless steel. High-quality materials, combined with precision German craftsmanship that ensures that this Sommer antenna will provide many years of maintenance-free performance.
Working Principe :
20 Meters
On this band the DJ2UT multiband beam system is a full-sized beam utilizing 1/2-wave elements without traps. The primary difference is that all elements are driven via a phasing line, in a fashion similar to the log periodic. This technique provides "monoband" gain or better without the narrow bandwidth commonly associated with such antennas. As on all bands, the compromise between forward gain and f/b ratio has been optimized for amateur use through actual on-the-air testing and not random selection.
15/17 Meters
Because the 20-m elements are approximately 5/8-wave long on these bands, the resulting high feedpoint impedance must be compensated for. Instead of resorting to "power-hungry" L/C traps, DJ2UT utilizes the capacitance found in the phasing line, in combination with another unique approach. Clustered about the feedpoint are 3 or 4 elements (depending on antenna model) in close proximity to each other. This combination of parasitic and driven elements simply and effectively brings the system impedance down to the desired 50 ohms. In addition, a special means of feeding the elements reduces the unwanted side-lobe radiation common to 5/8-wave systems.
10/12 Meters
Since the primary elements of this design or 1/2-wavelength on 20 m, they are approximately a full wavelength on 10 and 12 m. In the DJ2UT system, they are fed via the phasing line as "split" f-wavelength elements in a collinear fashion. This configuration also presents a high feedpoint impedance. As on 15/17 m, this high value is reduced to 50 ohms by the influence of 3 or 4 elements in close proximity, along with an auxilliary 12-m element.
30/40 Meters
By ignoring all elements but the longest (found at the rear of the boom), we may consider the DJ2UT antenna a simple dipole with a transmission line attached. Since this element, or dipole, is only 11.6 m (approx.) long, it is too short to be resonant on either 30 or 40 m and presents a capacitive reactance at these frequencies. On 30 m, the problem is solved by the simple addition of an L-C match. Similarly, 40-m compensation is achieved with a coil and/or coaxial capacitor. Since these networks are not in series with the antenna and only serve to cancel the "blind" reactive components, the problems of L/C trap loading are again avoided. It should also be noted that on 30 m, the 3- or 4-element cluster at the feedpoint serves as a director--providing some gain and a cardioid directive pattern in the larger models. On 40 meters, the mounting height of the antenna determines which element serves as radiator. As a result, the major radiation pattern may be in front or in back of the antenna, or even under 90 degrees, depending on antenna height.
6 Meters Option
Easy, you just have to fit under the shortest element in front of antenna a 2.95m long tube.
You can add some directors spaced approx 0.8m and increase gain without any disturb on others bands... that's magic like the magic band !
XP507 XP508 Caracteristics