###### Abstract  
Current progress in the development of new subterahertz instruments discussed in this paper, including antennas, high-power gyrotrons, and low-noise receivers, provides a wide range of possible applications. Atmospheric absorption has now become a major limitation in the application of such high-performance subTHz systems, and the choice of the optimal location of antennas for astronomical, radar, and communication systems is important. The latest results of studying the microwave astrocilimate in northern Eurasia are presented. Based on these studies, new perspectives and corrected plans for installing new antennas at the Suffia Plateau and in the Caucasus are formulated, and possible applications of new instruments such as radars for locating space debris and communication hubs for deep space communications, which are based on extremely-high-power gyrotrons and low-noise superconducting receivers, are discussed. Terahertz waves; MM and subMM waves; radars; space communications; atmosphere propagation; astroclimat; radio telescopes; gyrotrons; receivers +
Footnote †: journal: Applied Physics of the Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia, [EMAIL_ADDRESS] (G.B. ); [PERSON]ADDRESS] (M.G. ); [PERSON]ADDRESS] (A.G.); [PERSON]ADDRESS] (A.G.); [PERSON]_ADDRESS] (A.G.); [EMAIL_ADDRESS] (A.G.); [EMAIL_ADDRESS] (G.S.) Footnote †: journal: Applied Physics of the Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia, [EMAIL_ADDRESS] (G.B. ); [PERSON]ADDRESS] (M.G. ); [PERSON]ADDRESS] (A.G.); [PERSON]_ADDRESS] (A.G.); [PERSON]_ADDRESS] (A.G.); [EMAIL_ADDRESS] (S.S.)  
Footnote †: journal: Applied Physics of the Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia, [EMAIL_ADDRESS] (G.B. ); [PERSON]  
Waves shorter than the subTHz ones (shorter than 0.3 mm or over 1 THz) are mainly based on the photonic technologies, and up to optical range in its near-IR part, they have practically no transparency windows when operating on the Earth at the sea level and slightly higher, except only extremely exotic cases like the high Atacama Plateau [2]. In recent decades, the subTHz range has been a most actively and dynamically developing research and development area. The subTHz range promises and has already given unprecedented breakthroughs in astrophysics: specifically, the network of a dozen subTHz antennas included in the Event Horizon Telescope (EHT) [3] has made it possible to see the shadow of a black hole and identify different types of black holes. In telecommunications, subTHz radiation will provide both deep space communication channels of unprecedented capacity [4], which ensure a data transfer rate being quite close to that of optical channels and give new prospects for the terabit capacity of terrestrial mobile communication at 6G and beyond [5]. There are important tasks for subTHz radar, especially in the context of sounding space debris and other space objects, including extremely small ones [6; 7]. Certainly, very good progress has been achieved in the development of contemporary tools for astronomy, space communications, and radars in the optical frequency range. Technologies of laser generation and CCD receivers using the optical wavelengths are more impressive and open up the unique possibilities for astronomy, communications, and radars. Examples of remarkable developments are described in a lot of publications, and some of them are commented upon below. When preparing this article, we were primarily motivated by the progress of the technologies that have been developed in the last decade for generating and receiving subTHz radiation, and the current progress in the worldwide development of subTHz antennas and the 70 m RT-70 antenna of the Suffa observatory, in particular. However, optical methods do not resolve all problems, and different spectral windows are needed for the operation of radars, telescopes, and communication channels in the atmosphere.