Figure 1.

The input parts of radiometers with primary feeds are placed on secondary mirror focal line taking into account a task to minimize losses in the front-end waveguides and reduce aberrational scatter at short wavelength range. This enables the problem of efficient observations over the whole feed cabin No. 1 frequency range. From the right of the picture is a new developed three-frequency feed with matched phase center at the wavelengths 13, 31 and 49 cm, from the left is a new version radiometric system "MARS-2".
The scale drawing of secondary mirror No. 1 focal line is shown in figure 2.

Figure 2.

Intervals between of primary feeds centers and their strap reading are given in millimeters.