Sommer XP40 Series Beam Antennas

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Active Elements

20 m

2x driven full size (1/2 wavelength) elements
LOG-1 + LOG-2

15/17 m

2x extended 1/2 wavelength plus elements about 5/8 wavelength long
LOG-1 + LOG-2 + EL-1B on 15 m + EL-1C on 17 m

10/12 m

4 x 1/2 wavelength collinear elements 2 x 2 side by side
LOG-1 + LOG-2 + EL-1A + EL-2A + EL-1B as 3/8 radiator

30/40 m

All driven elements
LOG-1 + LOG-2 + EL-1B + EL-1C + EL-2A as "C"

The XP40, which measures only 2.4m (8 ft.), is a small beam that offers superior performance. Compared side by side with equivalent 3-element monobanders at 18m/60' height, the XP40 series antenna brings better DX results on 10 and 15 meters, and about the same results in gain and directivity on 20 meters. The model XP404 antenna is shown in figure A. In this configuration, gain on the various bands is as follows:

On 20 meters the antenna has two actively driven elements that provide a solid 5.5 dB/D forward gain.

On 15 and 17 meters the antenna has two directly fed 5/8-wave elements that form a typical band gain of 5.5 dB/D in conjunction with element 1B. Operation on 17 meters requires an optional 8.2 m (26 ft) element at boom location Z. This element will function similarly on 15 meters, but will not influence operation on 10 or 20 meters.

All elements are "working" in the 10 and 12 m bands and contribute to a total of 4-6 dB/D gain.

The 40 m band is activated by use of an individual power coil mounted at Y, which yields a 0 to 2 dB/D gain on this band.

Remember, a 3-element monoband beam has 4 to 6 dB/D (see ARRL Antenna Book).

Notes:
* Gain determined in the main lobe as described in the ARRL Antenna Book, 14th ed. pg. 15-23. Measurement accuracy according to CCIR plus/minus 2dB.
** F/B ratio and SWR vary according to conditions--e.g., electrical height above ground.
*** Plus or minus 10%

Sommer Antennas

P.O. Box 710
Geneva, FL 32732
Phone:( 407) 349-9114 | Fax: (407) 349-2485