SPM (MT-MR Line) Mobile Microwave Radio Link

The mobile multi-channel microwave system SPM is available either in analogue and digital version. The working frequency can be any 500 MHz band between 6 GHz and 19 GHz and the modulation can be either analogue (FM) or digital (QPSK, 16QAM, 32QAM, 64QAM, 128QAM, 256QAM).
The system is composed of indoor and outdoor units; a 75 Ohm coaxial cable connects both units. The Outdoor equipment is composed of tripod complete with panoramic head, base plate, orthomode transducer, parabolic dish complete with feeder and one or two RF Heads.
The tripod is of heavy duty type and has telescopic legs with orientable feet, manufactured using light and robust aluminum alloy. The panoramic head, secured to the tripod with a single large threaded cylinder, permits 360° horizontal and ±15° vertical position adjustment with fine angle resolution and final secure locking.
The base plate, assembled on the panoramic head, supports one or two RF heads, the orthomode transducer and the parabola. The orthomode transducer is the interface between the RF head/s and the vertical and/or horizontal polarisation branches of the feeder. Three parabolic dish sizes are available: 60 cm, 90 cm, 120 cm. The feeder is Cassegrain type, double polarization with circular waveguide.
The weatherproof RF heads capable of being installed on the base plate can be (depending on the application) single Transmitting or Receiving Head (Simplex), two Transmitting or two Receiving Heads (Double Simplex) or a Transmitting and a Receiving Head (Duplex). The RF head is weatherproof and is installed near the parabola in order to reduce waveguide losses. Each RF head is connected remotely to the control unit through a coaxial cable. The connection cable must have an impedance equal to 75 Ohm with tolerance less than 2 Ohm and must have double screened cable; the RG216 is suitable for this purpose. The connectors are LEMO (FFA.3T.275.CTAY11). The length of the cable RG216 can reach 300 m; and this determines the choice of the correct value of equalisation.