MINILOOP TUNABLE ANTENNAS TRANSMIT - RECEIVE

Transcription

1 ... A ntenn a R es earch MINILOOP TUNABLE ANTENNAS TRANSMIT - RECEIVE Our low profile MLA series Miniloops and very low profile MLH series half loops are high power communications antennas. These antennas are designed for installation in virtually any environment, especially those where space is limited. MLH series HF band tuned loop antennas are ideally suited for hardened site applications. The antenna can be recessed into a cavity with a cover such that there is little or no exposure above ground. Miniloop antennas can be mounted on vehicles for ground wave direction finding by rotating the loop until its null points toward the target transmitter. The Miniloop has an almost hemispherical overhead pattern, allowing excellent skywave communications at all freqencies in the operating banc. Its performance is particularly good for short-haul communications where high take MLA-1/E ON A VEHICLE An MLA Series Miniloop antenna system is supplied with the basic loop antenna, a vertical mast, a bolt-down base, and a rack-mountable tuning unit. A hinged base/mast assembly is available for transporting the loops in a flat position on a vehicle without disassembling the loop. The MLH-324 or MLH-2/D antenna system is supplied with the basic half-loop antenna, bolt-down base plate, and a rackmountable tuning unit. Auto-tuned Miniloop systems include the MDT-1.0/A automatic digital tuner, which provides hands-free operation and transmitter interlock protection. The MDT Tuner reduces the full range tuning time to less than 10 seconds. MLS antennas are designed to be turned to the desired frequency of operation by the use of a small fiberglass tuning tool. Only a single tuning adjustment is required to resonate the antenna at any frequency within its band of operation to a SWR not exceeding 2 : 1. Pretuned loops such as our MLS-470 are designed for single frequency applications where the signal to noise ratio is critical. MLA

2 MINILOOP TUNABLE ANTENNAS TRANSMIT - RECIEVE MLS-310 MLH-310/A A separate catalog is available for loops, whips, dipoles and electrically small directional antennas for HF applications. The MLA and MLH series tunable loop antennas (MINILOOPS) are ideal for HF communication and installation in any environment, especially when available space is limited. The Miniloops are most suited for colocated antennas, which are operating at slightly different frequencies. The DPA series broadband HF antennas are designed for use in polarization diversity receiving systems. The PLC series HF cross loop antennas provide omnidirectional coverage. For more information on these and many other antennas for your HF applications, call toll free ANTENNA or , or fill out the online information request form. Phone: Fax: sales@ara-inc.com 73

3 NETWORK ARRAYS WIDEBAND DIRECTIONAL ANTENNAS Our PNA series antennas are physically small and ideally suited for applications where directivity is important and small size is critical. PNA antennas are designed to exhibit a directional pattern comparable to that of a well designed log periodic antenna. A typical VHF PNA antenna, however, is only one tenth the size of a log periodic. An excellent balance of the dipoles with respect to ground helps to reject locally generated (common mode) interference. The pattern exhibited by a PNA antenna in the "H" plane is essentially a cardioid. The deep null at the rear of the pattern can be used effectively to reject a strong signal from one direction. These miniature directional antennas are practical for use with a rotator for rotation in azimuth to minimize interference from noise sources in the azimuth direction. An optional broadband low-noise preamplifier can be used with the antenna to overcome transmission line loss and other system losses inherent in small antennas. The use of this amplifier is not essential if a receiver with high sensitivity is used. A PNA antenna integrated with a pre- amplifier and rechargeable PNA-230/A batteries or a power supply provides a directional receiving system of an unusually small size. The directivity characteristics are essentially independent of frequency, with an efficiency sufficient to meet the necessary criterion of masking the receiver noise with the atmospheric noise. A cross-polarized PNA antenna system exhibits a directional pattern in both the vertical and horizontal polarization planes that is comparable to that of a well designed log periodic antenna over the entire frequency range of operation. The basic PNA design may be modified to provide a PNM (see direction finding antennas) series antenna which is ideally suited for direction finding capabilities. The modification provides two selectable patterns in addition to the standard unidirectional cardioid pattern normally used for receiving purposes. The first of these is a bidirectional "Figure-Eight" pattern. This pattern exhibits two sharp nulls which can be used to obtain accurate bearing information. After obtaining a bearing, one can resolve the 180 degree ambiguity by switching to the cardioid pattern. The second additional pattern is omnidirectional which can be used for general search and surveillance. PNA-1721/A 74

4 NETWORK ARRAYS WIDEBAND DIRECTIONAL ANTENNAS SPECIFICATIONS IMPEDANCE: 50 ohms, nominal F/B RATIO: 15 db minimum WIND AND ICE: OPERATIONAL: 50 mph PATTERN: Cardioid in "H" plane SURVIVAL:100 mph without ice, DIRECTIVITY: 5-7 dbi 50 mph with 0.5" radial ice MATERIAL: Aluminum, Fiberglass FREQUENCY POLARIZATION ELEMENT LENGTH BOOM LENGTH WEIGHT (LBS / KG) CONNECTOR (MHZ) PNA-2/B 2-30 Vertical 12 ft 8 ft 45 / 20 N PNA-230/A 2-30 Dual 12 ft 8 ft 50 / 23 N PNA-2010/A Dual 80" 40" 35 /16 N PNA-3020/C Linear, Variable 40" 20" 6 / 3 BNC PNA-3020/XP Linear, Dual 41" 20" 15 / 7 N PNA-1721/A Linear 24" 17" <1 lb BNC PNA-3020/C E-Plane PNA-3020/C RADIATION PATTERNS AT 200 MHZ 50 TYPICAL E-FIELD ANTENNA FACTOR FOR PNA /C AFE (db/m) FREQUENCY MHz H-Plane 75

5 SPIRAL ANTENNAS CAVITY BACKED SPIRALS Our CBS series cavity backed spirals are broadband antennas designed for ECM, surveillance, direction finding, telemetry, and flush mounted airborne applications. These spirals can be used as a separate component antenna or as broadband feeds for reflector type dish antennas. All CBS series spiral antennas exhibit an excellent impedance match and radiation pattern control over the broad operating bands in a compact and lightweight package. These spirals are ideally suited for amplitude matching and phase or gain tracking. The unit - to - unit uniformity and frequency independent performance is ideal for airborne monitoring receiving systems. All cavity- backed spirals are available in RHCP or LHCP. These spirals have been designed to operate in a harsh environment and meet the extremes of the MIL-E-5400 Class 2 specification. Cavity backed spiral antennas covering other frequency bands and having various connector configurations are also available. SPECIFICATIONS: CAVITY BACKED SPIRALS CBS-512/A CBS-218/A CBS-28/A FREQUENCY GHz GHz GHz BEAMWIDTH 3 DB 10 DB ( to ) >65 nom. (any principle plane) ( to ) GAIN 4 dbil nominal -3 to 0 dbil (2-4 GHz) 0 to 1.5 dbil (4-18 GHz) 2 dbil nominal VSWR (MAX.) 2.0 : : : 1 POWER 4 W 1 W 4 W AXIAL RATIO 4 db 3 db 45 4 db POLARIZATION RHCP or LHCP RHCP or LHCP RHCP or LHCP CONNECTOR SMA female SMA female* SMA female SIZE 1.25" Dia. x 2.3" L. 2.6" Dia. x 1.6" L. 3.0" Dia. x 2.0" L. WEIGHT 3 oz. 6 oz. 4 oz. * Off centered and tilted connector configuration available (Model CBS ) 76