[Vlad95]

This is most likely the result of poor tuning of the input path. The tuning procedure is described in detail in the document you attached in the "Tuning Compensators" section.

I also strong recommend adjusting the oscillator tuning range after the first stage of IF tuning. Compensator #8 adjusts the low-frequency range to 520 kHz, and compensator #3B adjusts the high-frequency range to 1720 kHz. After this, you can proceed to adjusting the maximum sensitivity to 1600 kHz using compensator #3A and to 580 kHz using compensator #10. Since the settings are interrelated, it is recommended to repeat the tuning process several times for both low and high frequencies to achieve the best results.