JSC «Meridian» n. a. S. P. Korolyov at one point developed and mass-produced a wide-range microwave frequency meter of the 8-mm wavelength range UA Ч3-101. Over time, however, the device has become obsolete for a number of reasons, and the question arose of the need to replace it. Since the cost of foreign models of frequency meters with similar parameters available on the market is quite high, the enterprise’s capabilities in solving this issue were considered. The analysis showed that the development of a new similar frequency meter will also be quite expensive, but the modernization of the existing one might be much cheaper, since the enterprise has all the infrastructure for serial production of the upgraded frequency meter. This article describes technical solutions for the replacement of labor-consuming microwave components of the UA Ч3-101 frequency meter, such as microstrip and waveguide input microwave converters, as well as optimization of the frequency measuring process of the input signal, which allowed us to upgrade the device according to the requirements. The use of the developed broadband small-sized frequency converter in the modernized UA Ч3-101A frequency meter made it possible to simplify the circuit and the frequency measurement process as much as possible, to use only one input microwave converter, to significantly reduce the weight and size of the device, to abandon the labor-consuming and expensive waveguide components of the device, and to double the sensitivity upgraded frequency meter. The proposed technical solution allowed simplifying the production process of the frequency meter, making the device more convenient to use. In addition, due to the optimization of circuit and design solutions in the upgraded frequency meter, it was possible to combine the counter and the gate driver on the same board, combine the reference frequency block with a 100 MHz tunable generator, abandon the switch, which allowed reducing power consumption and increasing the reliability of the device.