New analysis comes to light regarding high frequency trunk communications used by Russia’s strategic integrated air defence system.
Regular Armada readers will be aware of our deep interest in Russian military radar, electronic warfare and communications systems. Our fascination with these capabilities is enabled in no small measure by the work of EW Analytics LLC. Based in the United States, the company uses publicly available information to produce highly respected analysis of Russian military electromagnetic capabilities. EW Analytics LLC regularly shares its analysis, which we summarise for our readers, and you can find some previous examples of our summaries here.
The company shared its recent analysis of two High Frequency (HF: three megahertz/MHz to 30MHz) antenna arrays located in Russia’s Arctic region. The Russian military has an Arctic Trefoil installation in the Franz Josef archipelago in the north of the region. Arctic Trefoil installations follow a similar design, ‘Trefoil’ being a reference to the installation’s three-wing building design. Next to the installation are two fenced fields each covering an area of one square kilometre (0.38 square miles). Each field contains an antenna array that EW Analytics LLC has discovered is connected to RPDRUM-1/5 HF radios, the antenna array of interest being referred to as Vh-60/12 in Russian.
The analysis continued that these antennas have been installed in a distinctive sloped/inclined configuration intended to increase the directionality of the transmitted signal as compared to conventional HF antenna performance which can be especially problematic in the Arctic. EW Analytics LLC has found that this distinctive sloped/inclined HF antenna array was part of a Russian Arctic-wide HF communication architecture that was proposed circa 2017. This was around the time that Arctic Trefoil became operational. Given that the antennas of this distinctive array are 60 metres (197 feet) in length it is likely that they handle traffic on frequencies of around five megahertz. The orientation of the antennas suggests them pointing south to areas like the Kola Peninsula. The peninsula is 1,550 kilometres (963 miles) to the southwest. It is home to several Russian military installations including Russian Naval Aviation’s Olenya airbase and the Zapadnaya Litsa naval base.
Arctic Trefoil
The Arctic Trefoil facility under examination is collocated with the airbase at Nagurskoye on Alexandra Land, one of the largest islands in the Franz Josef Land archipelago. Adjacent to the Arctic Trefoil is a set of three radomes; the one atop a mast containing a 12A6 Sopka-2 S-band (2.7 gigahertz/GHz to 2.85 GHz) air surveillance radar. EW Analytics LLC speculates that one of the HF radios/antenna arrays may provide trunk communications to share track data gathered by the Sopka-2 radar. The company believes the HF antenna array nearest the Sopka-2 radar is used for this role since it is collocated with an Aviation Guidance Point (AGP). AGPs are the Russian equivalent of Integrated Air Defence System (IADS) control and reporting centres. This HF link could help feed track data into the Leningrad Military District’s (MD’s) IADS. The Leningrad MD’s IADS will develop a Recognised Air Picture (RAP) of the airspace above the military district, and air approaches to it.
This RAP will be shared at the national level to help populate Russia’s strategic RAP covering the air and space above and around the country as far as the radar horizon allows. Whether this HF link is used all the time is unknown. EW Analytics LLC posits that the link may form a back up to trunk satellite communications which may support routine track data sharing. Interestingly, the analysis states that unlocated Russian air defenders have been reported to share track data across HF using Morse Code. Such transmissions are occasionally detected by European-based radio amateurs monitoring Russian high frequency channels. The other HF radio/antenna array at the base is close to the facility’s administrative and accommodation building. EW Analytics LLC deduces that this latter HF radio/antenna array may be used to carry non-tactical traffic.
Future deployments
Additional Arctic Trefoil bases have been constructed for the Russian military; one on Wrangel island in Russia’s far east Arctic region and one on Kotleny island in the country’s central Arctic region. EW Analytics LLC states that, so far, only the Arctic Trefoil facility at Nagurskoye appears to have been equipped with the Vh60/12 HF antenna array; an indication perhaps that this Arctic Trefoil has unique communications requirements. It will be interesting to see if other Arctic Trefoil facilities receive similar HF equipment in the future. Armada will share further details on this subject, and others, as and when they become available from EW Analytics LLC.
by Dr. Thomas Withington
