Submarine Matters strives to bring all manner of submarine topics to you the reader. To that end Anonymous reported on August 22 and Unknown reported August 23, 2023, on submarine reception of signals. Pete has done some English from another language editing and has also attempted more explanations of these highly technical topics, with lots of question marks ? when issues need clarification.
For the last 7 to 10 years NATO standard Link 11 due to a low data rate? deficiency has been upgraded to Link 16 [maybe a tactical version of Link 22 ?]. With Link 22 being a packet, internet protocol (IP) system in the HF and UHF radiofrequency bands. Link 22 operates in the 1 GHZ range to have broader bandwidth for higher bit rates to transmit maps and video, etc.
Link 22 allows for very small antennas (A quarterwave is about 7 cm) but at these frequencies you have to be in the line of sight and to achieve high gain using a small parabolic dish (30/40 cm?) on the surface (searching and tracking automatically the right satellite) is needed.
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France's Barracuda SSNs use Links 11, 16 and 22 via the
Thales DiveSat (see above) antennas. The German Aeromaritme company has specific radio masts probably functionally identical.
This is "passe" (designed 15/20 years
ago) however with the emergence of Phased Array matrix detectors at very low cost
(Starlink internet terminal includes a flat antenna that can scan and track satellites automatically (valued) at US$500.
"A submarine towing a flat plastic black sheet 30 cm in size on the surface..(with electronics and a power source, FO? link for the
data) Detection?..Retrofit likely." [Pete knows not what is meant by this!]
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As for buoyant wire antennas (towed by subs - see above) they are useful in the HF band, at 10/30 Mhz, for traditional radio links over long distances, up to 10,000 miles if the seasons and the ionosphere are ok
There is no need for an (indiscrete) surface wire with VLF [see NEREIDES' artwork above] because in the 3/40 KHz the Electromagnetic (EM) field penetrates down to 20 meters. Although a long surface wire is far better for reception. However the bandwidth at these frequencies is in a fraction of kbits/sec order of magnitude, less than the old traditional analog phone using a landline of Thomas Edison in 1890.
Pete Comment
It is always assumed that submarines merely receive messages and "never transmit" to Headquarters for instructions. This is demonstrably false.
It need be remembered that concerning the first and only time a nuclear submarine has torpedoed a ship in battle - HMS Conqueror sinking General Belgrano in 1982 - HistoryNet records:
“…Conqueror duly reported its change of direction to London at 1400 Zulu [time]. Then, despite problems with its communications equipment, at 1710 Zulu the British submarine received and acknowledged the new [Rules of Engagement] ROE and orders to attack. At the same time Cmdr. Chris Wreford-Brown, Conqueror’s captain, transmitted his intention to strike the enemy..."
Presumably HMS Conqueror used an HF, UHF or VLF? radio transmission encrypted and aimed at
a satellite for security? to report to London and to acknowledge London's orders.
See Comments from Anonymous at 9/01/2023 9:53 PM and Shawn C. at 9/01/2023 10:25 PM clarifying some of the issues above.
Hi Pete some clarification on my previous post
ReplyDeleteSorry again to be long and a lttle "professoral'
I hope it helps people not familliar with these technologies
The physics of telco transmission/radio..ect states that the maximum bandwith /data rate (same concept)is fairly proportionnal ,at equivalent error rate, to the Frequency .Thus VLF can transmit less than HF ,which in turn tansmit less than VHF , UHF and the following radar bands.However the propagation goes the other way round.VLF the world, Satellite bands, line of sight closer to optical.The exception is HF in the 15/30 Mhz band where very long transmission is achieved if the ionosphere provides a kind of wave guide ,more at night and in tha absence of solar eruption
Link 12 is a modernized version of linK11.It has mostly a low bit rate ( expressed in 100 kbits rate and usually works in the HF/VHF. It was conceived to be a tactical radio ++(digital , encryption, difficult to intercept thru frequencies hopping, data transmission., organized as a packet network to be robust,..ect).The advantadge is that in the HF /Vhf mode line of sight is not needed but essentially tactical info can be exchanged . up to 100/200 km with certainty
Typically an observer , with modern ,(GPS/Inertial,connected binocular )would acquire an ennemy vehicle and transmit in real time , at the tip of its finge,the location of the target to a modern (inertial/GPS /ballistic computer..)artillery piece 20 km away that could fire with very limited human intervention ,if needed, reaching the target in 30 seconds.That is the objective at least and it is met if the equipment, the people ..ect are right
This what network centric warfare is all about. P sensors detecting N targets and the battle management system,the "C4I" developpindg a hierachy and allocating K weapons systems.This is alreaduy how modern AA defense works today in Nato or Israel for quite a few years
Link 16 has a more strategic objective , ie to transfer data in the Mbits range + (maps, video,.in an internet style protocol.It use more the GHz range, which require line of sight, in practice satellite.To achieve, low error rate/high bit rate an antenna with high gain is needed (a small "Marconi", antenna,a vertical stick, 7cm,used in GPS at similar frequencies might not be sufficient)A small parabola , automatically tracking the satellite is needed.
Thales DiveSat for the Barracuda with the various Syracuse satellites or other types is here the typical example found as well in most Nato Navies, as for instance Italy, Belgium.. share the Syracuses and excess capacity can be leased (to the friends if possible..!)Th boyant antenna works quite well in the HF band
SSBN never emits, but not SSN which occasinally would do .ELINT satellites and Elint planes ("à la""Rivet Joint" ) are effectve
Just look at the number of Russian General killed early on..(They were not using smart phone;; (as read in the press!) very likely they were close to the antenna and SIGINT analysis can differentiates the difference beetween a tank platoon commander and a division HQ traffic.Evidenly not done by the UKr..! hence the Sm.Phone story..
The developpement of phase arrays antennae, flat sheet, where the scanning is done electronically is likely to change that as the absence of mechanical system can makes it very low cost and ultimately might be disposable (in the sumbmarine weapons realm of costs!)
Hi Pete,
ReplyDeleteI mentioned the Nereides submarine buoyant wire antenna system was a relatively recent upgrade for Malaysia's Scorpene - the 'bump' at the back of the sail https://navyrecognition.com/index.php/naval-news/naval-news-archive/2023/10281-lima-2023-news-online-show-daily/13185-lima-2023-malaysia-s-navy-displays-scorpene-class-submarine-kd-tunku-abdul-rahman.html
A similar facility is present on the INS Kalvari, https://twitter.com/livefist/status/940924782836555777?s=20