TMC/P-R/P Digital Ready Mobile Radio Link

The Digital Ready Mobile link TMC/P is able to transport either an analogue or a digital IF signal. The frequency can be chosen in the range from 2 GHz to 19 GHz.
The link is composed of: a transmitting part formed of a control unit TCU and an external head TMC/xxP; a receiving part formed of a control unit RCU and an external head R/xxP.
The connection between the control unit and the respective external head is made by a single coaxial cable (RG216).
The external RF heads can be fed and remote controlled by the TCU/RCU; if the integrated analogue modulator and demodulator are required, the control units will be the TCU/R/A and RCU/R/A; in case of digital modulation/demodulation, the external digital modem DDM310 is required.
The transmitting head of the TMC/xxP is implemented in a waterproof casing in order to be installed near the transmitting antenna.
This solution reduces to minimum losses from the cable that feeds the antenna and offers practical advantages in situations where transmission sites are often changed (Mobile links).
The transmission head is fed by a control unit (TCU) through a coaxial cable (RG216) through which the continuous feeding supply (approx. 24V not stabilized) and the modulated IF signal are sent.
The transmitting head converts the IF signal into an RF signal (2 GHz to 19 GHz) and successively amplifies to the output power.
The control unit provides to the coaxial cable the multiplex formed by the continuous feeding supply and the IF signal at 70 MHz.
The receiving head (R/xxP) is also waterproof in order to be installed near the receiving antenna, giving also at the receiving end the advantage of reducing to minimum losses of the cable that feeds the antenna and offers practical advantages in situations where transmission sites are often changed (Mobile links).
The receiving head, the same as the transmitting head, is fed by a control unit (RCU) through a coaxial cable (RG216) whose function is to send the continuous feeding supply (approx. 24V not stabilized) and, in the opposite direction, bring down the 70MHz IF signal to the control unit.
The receiving head converts the received RF signal (2 GHz to 19 GHz) into the intermediate frequency (70 MHz) and successively amplifies to the level required in order to feed it to the control unit.
The control unit needs to provide, through the coaxial cable, the continuous feeding supply to the aerial head, and extract the modulated IF signal at 70MHz.
The coaxial cables between the control units and the external RF heads need to have an impedance of 75 Ohm with a tolerance of less than 2 Ohm and they must be double shielded.
The RG216/U cable is suited for this purpose. The foreseen connector is a LEMO connector, model FFA.3T.275.CTAY11.
The length can be up to 200m, the correct value of the equalization of the slope attenuation must be set up according to the length by the 10/100/200 control under the configuration menu of the relative control units. The selected position must be the nearest one to the one actually used.

How to use the TMC/xxP and R/xxP
The external heads can be installed on tripods or on mast. In the first solution, for some frequencies, is possible to have two aerial heads on a single tripod, using a double polarization or a diplexer; for example, two simplex or one bi-directional. A 60cm parabola is used with the feeder placed at the back of the head.
The second configurations offers more than one solution: It is possible to Install the aerial heads with feeder and 60cm parabola offset integrated in the aerial head; alternatively one can use parabolas with single or double polarization, and a larger diameter according to the distance of the link. This system allows installing, with appropriate cradles, up to four aerial heads in the most various configurations.