
The Many Methods of Communicating with Submarines - gumby
https://hackaday.com/2020/07/15/the-many-methods-of-communicating-with-submarines/
======
hchz
I was disappointed with how much this missed:

[https://en.wikipedia.org/wiki/Fleet_Satellite_Communications...](https://en.wikipedia.org/wiki/Fleet_Satellite_Communications_System)

[https://en.wikipedia.org/wiki/UFO_(satellite)](https://en.wikipedia.org/wiki/UFO_\(satellite\))

[https://en.wikipedia.org/wiki/Milstar](https://en.wikipedia.org/wiki/Milstar)

[https://en.wikipedia.org/wiki/Global_Broadcast_Service](https://en.wikipedia.org/wiki/Global_Broadcast_Service)

[https://en.wikipedia.org/wiki/Defense_Satellite_Communicatio...](https://en.wikipedia.org/wiki/Defense_Satellite_Communications_System)

[https://en.wikipedia.org/wiki/Advanced_Extremely_High_Freque...](https://en.wikipedia.org/wiki/Advanced_Extremely_High_Frequency)

[https://en.wikipedia.org/wiki/Minimum_Essential_Emergency_Co...](https://en.wikipedia.org/wiki/Minimum_Essential_Emergency_Communications_Network)

The interesting aspects of how USN submarines access these systems doesn't
appear to be openly available.

~~~
matheusmoreira
> FLTSATCOM 7 and FLTSATCOM 8 have been used for repeating UHF Satcom
> transmissions by unauthorized radio users particularly in Brazil, including
> criminals, illegal loggers, truckers and individuals located in remote
> areas.

I wonder how much disruption they're causing...

------
SaberTail
My favorite attempt to get the Department of Defense to pay for physics
research is a paper that suggests building a muon storage ring and using that
to generate a beam of neutrinos to communicate with submarines[1].

The physical principals are pretty sound. We do already generate neutrino
beams, like at Fermilab[2]. And we do have the ability to detect neutrinos in
water, optically as ANTARES[3] does, or acoustically, as SAUND[4]
demonstrated.

There are some serious engineering challenges to building a muon storage ring,
which is why we don't have any. If we could build them, we could build a muon
collider. Muon colliders would be great. Muons are elementary particles, and
don't have all the garbage inside that a proton does, and so you'd get very
clean signals out of such a collider, unlike the LHC. And since muons are much
heavier than electrons, it's easier to get them to very high energies without
losing a lot of power to synchrotron radiation.

[1] [https://arxiv.org/abs/0909.4554](https://arxiv.org/abs/0909.4554) [2]
[https://www.fnal.gov/pub/science/particle-
physics/experiment...](https://www.fnal.gov/pub/science/particle-
physics/experiments/neutrinos.html) [3]
[https://antares.in2p3.fr/Overview/index.html](https://antares.in2p3.fr/Overview/index.html)
[4] [http://saund.stanford.edu/saund1/](http://saund.stanford.edu/saund1/)

~~~
Enginerrrd
I've often wondered about the feasbility of a private firm doing something
similar to _dominate_ the HFT scene by getting a massive lead on information
from the opposite end of the globe.

~~~
schoen
Avoid the pesky curvature of the Earth's surface by going directly along a
chord through the mantle rather than along a great circle?

Using [https://planetcalc.com/7725/](https://planetcalc.com/7725/) and
[https://planetcalc.com/73/](https://planetcalc.com/73/) I just concluded that
the straight-line chord distance between Tokyo and San Francisco is 1552 km
whereas the great-circle distance is 8270 km. (Neither of these is very
precise because it's unclear where in each city you should measure from, and
unclear whether either calculator uses data about the irregularity of the
Earth's curvature.)

It does make a noticeable difference for HFT applications, I guess: 1552 km/c
is about 5 ms while 8270 km/c is about 28 ms. (The neutrinos might do better
in another way because I guess light in a fiber doesn't directly follow the
curve of the fiber itself, since it's getting repeatedly reflected off of the
inside surface of the glass.)

~~~
femto
Are those numbers correct? In the worst case, the chord would be the diameter
and the great circle would be half the circumference, so the ratio would be
(pi.d/2)/d = pi/2 = 1.57.

For fun the cos rule can be used to derive a general formula for the ratio of
great circle to chord, given the angle (theta) in radians subtended at the
centre of the Earth:

theta / sqrt( 2-2.cos(theta) )

where: theta = (great circle distance) / radius

(Assuming I haven't mucked up my algebra.)

\--

Not sure why my comment is rendering in italics. No emphasis is meant. Figured
it out, it was the asterisk I used for a multiplication symbol.

~~~
schoen
Thank you for the sanity check. It looks like the web site has a bug!

------
sparker72678
If you like this kind of stuff checkout "Blind Man's Bluff: The Untold Story
Of American Submarine Espionage"

There are so many fascinating details about submarine operations that are now
unclassified (and makes you guess about what things are like that _are_ still
hidden). From communications to the underground listening stations to
attempting (and succeeding) in wire-tapping soviet communication cables, to
attempting to lift a wrecked foreign submarine right off the ocean floor.

It's an amazing read and very well written.

~~~
dfsegoat
The audiobook has some nice extra commentary as well.

That book blew the cover off missions that hadn’t been known to the public at
all, so it was a bit controversial at release - the commentary touches on all
that.

 _Red November_ and _The Taking of K129_ are also great reads along these
lines.

~~~
sparker72678
I loved the audiobook, but somehow I missed the controversy part. Thanks for
the recommendations!

------
fortran77
I worked on the Eaton AIL CVLF radio receiver, which was the one of the first
digital radio receivers done in the late 1980s. Because the frequencies used
to communicate with subs were around 19 kHz, the CPUs of the time were just
fast enough to do the signal processing. We used the Fairchild 9445 which was
essentially a Data General "Nova 4" on a chip.

This receiver was used to receive launch commands. It received teletype data
that was printed on a Model 29 Teletype. The encryption keys and the key
generator used on this project were compromised by the Walkers, a family of
spies (See [https://news.usni.org/2014/09/02/john-walker-spy-ring-u-s-
na...](https://news.usni.org/2014/09/02/john-walker-spy-ring-u-s-navys-
biggest-betrayal) )

The Submarines dragged a wire antenna that was used to receive the VLF radio
signals, that were transmitted from several megawatt sites within the US and
beyond.

------
throw0101a
What, nothing about NATO's JANUS?

> _JANUS performance has so far been evaluated by many collaborating partners
> at centre frequencies from 900 Hz - 60 kHz and over distances up to 28
> kilometers in waters all over the world._

> _JANUS packet and bit error rates have been computed as functions of the
> signal to the noise ratio (SNR) and time spread over periods extending from
> hours to months. Signal correlation times have been computed and long-term
> experiments by CMRE(external link) in 2008 and 2009 have helped quantify
> robustness during variable environmental conditions._

* [http://www.januswiki.com/tiki-index.php?page=About+Janus](http://www.januswiki.com/tiki-index.php?page=About+Janus)

Toolkits available under GPLv3.

* [https://www.popularmechanics.com/technology/infrastructure/a...](https://www.popularmechanics.com/technology/infrastructure/a27247/nato-janus-underwater-communication/)

* [https://spectrum.ieee.org/tech-talk/telecom/wireless/nato-de...](https://spectrum.ieee.org/tech-talk/telecom/wireless/nato-develops-first-standardized-acoustic-signal-for-underwater-communications)

* [https://robohub.org/janus-creates-a-new-era-for-digital-unde...](https://robohub.org/janus-creates-a-new-era-for-digital-underwater-communications/)

~~~
notthetup
JANUS looks great on paper, but is pretty restrictive for doing anything
useful in real life.

At the standard frequency bands they've chosen (9440-13600 Hz), with the type
of coding scheme they use FH-BFSK, the bandwidth is too limited (4KHz -> ) to
do anything except service discovery.

Having said that, I agree, it should have been mentioned.

~~~
throw0101a
> _JANUS looks great on paper, but is pretty restrictive for doing anything
> useful in real life._

Were they going for reliability rather than bandwidth?

Are there any alternative 'underwater modem/codec' standards?

------
hchz
You can actually hear some forms of Gertrude through the hull!

I slept with my head right near the hull, and when we did a certain kind of op
where it was in use, you could faintly hear what sounded like a home modem.

~~~
kayfox
You can hear it in the movie The Abyss as well, since Cameron is a stickler
for accuracy.

------
FabHK
> “It sometimes seems hard to believe that we humans have managed to explore
> so little of what we have so much of: the seas.”

Apparently fewer people have been to the bottom of the Mariana trench (between
11 and 12,732 km away from you) than to the moon (about 400,000 km away from
you).

~~~
RandomBacon
Visiting the bottom of the Mariana Tench might be feasible for some people
here.

Apparently there are three slots available on a first-come-first-serve basis,
for $750,000.

[https://www.cnn.com/travel/article/marianas-trench-
challenge...](https://www.cnn.com/travel/article/marianas-trench-challenger-
deep-dive/index.html)

Climbing Everest used to be a bucket list item for me, but not anymore after I
hear how bad it's gotten over the years.

Going into space seems more feasible for me than the trench, only $250,000.

~~~
FabHK
Yeah, Mt Everest... nobody goes there anymore, it’s too crowded ;-)

I happened to be in Guam in 2012 and in some dodgy dive bar (...) ran into the
crew that took James Cameron down to Challenger Deep, only the second manned
descent ever. Didn’t believe them a word until I saw my couch surfing host
dancing with Cameron.

~~~
dragonwriter
> Yeah, Mt Everest... nobody goes there anymore, it’s too crowded ;-)

Mt. Everest is the kind of place where that could be literally true (though I
don't think it is, yet), if you count corpses as part the crowding...

~~~
obmelvin
While I do feel like it is still an appropriate joke to make in the sense that
it sounds ridiculous to say you aren't interested in Mt Everest because its
too crowded, sadly it seems we have already reached that point in time -
[https://www.washingtonpost.com/world/2019/05/24/mount-
everes...](https://www.washingtonpost.com/world/2019/05/24/mount-everest-has-
gotten-so-crowded-that-climbers-are-perishing-traffic-jams/)

------
elchief
I recall an X-Files episode where a woman was affected by the transmission of
a ULF or ELF antenna and it was making her crazy. Was a fun episode

Here it is [https://en.wikipedia.org/wiki/Drive_(The_X-
Files)](https://en.wikipedia.org/wiki/Drive_\(The_X-Files\))

~~~
gorgoiler
Ah yes: the other Vince Gilligan TV show starring Bryan Cranston.

------
peter_d_sherman
>"While the high frequency (HF: 3 MHz to 30 MHz) and low frequency (LF: 30 kHz
to 300 kHz) bands are perfectly capable of reaching across the globe thanks to
ionospheric refraction, the high conductivity of seawater rapidly attenuates
signals in these bands.

Dialing down the spectrum a bit, the very low frequency (VLF: 3 kHz to 30 kHz)
band starts to exhibit decent penetration of seawater, down to a depth of
perhaps 20 meters."

[...]

>"Going even further down the spectrum, signals in the extremely low frequency
(ELF: 3 Hz to 30 Hz) band are capable of penetrating 120 meters of seawater"

Submarines aside, this is tremendously interesting how specific mediums (in
this case, salt water) either act as transducers or attenuators for different
radio frequencies.

Now, when a radio frequency is influenced by some form of matter (in this
case, salt water, and at higher frequencies, attenuation), it might be because
the matter and the radio frequency are somehow related.

In other words, perhaps future scientists will discover that the molecules of
water are resonating at a frequency which is a much higher harmonic than the
radio waves that they block. And/or perhaps their frequency is somehow related
to the much lower frequency radio waves that they conduct.

See, it's sort of like any attenuator can act as a conductor (or vice versa),
but the frequency or set of frequencies used makes the determination as to
whether the medium in question is going to attenuate or conduct...

Compare this concept to resistors in electronics.

They resist standard DC... but what about AC at a certain frequency, or pulsed
DC at a certain frequency?

The higher the frequency (to a certain point when space becomes conductive and
thus dissipative with respect to the circuit), the more a resistor should
become a conductor...

Also, observation: The reason why distance is lost (in seawater, but also
other mediums) when higher frequencies are used, is typically because power is
converted into frequency, which then, in the case of a standard radio wave,
expands into space as a sphere, that is, it's a inverse-square-law power loss
over space.

Compare radio waves to lasers; lasers do not lose power in accord with the
inverse-square-law over space...

~~~
bertjk
>They resist standard DC... but what about AC at a certain frequency, or
pulsed DC at a certain frequency?

Um.. yes. This is actually exactly how you model coupling capacitors when
analyzing circuits. You use them to connect two nodes. Apply DC and no current
flows through once the capacitor is charged. Apply AC and the signal is
transmitted to the other side. The strength of the transmitted signal is
dependent on frequency and of course whatever else you have connected to the
circuit.

------
codezero
I remember researching this in 2008 and I thought satellite based lasers were
already in common usage (sending signal to specific known surface location and
also receiving from that location using the surface of the ocean as the medium
that the sub and satellite read.

This was a while ago so no links maybe I’m misremembering.

~~~
dylan604
they do this with directional encrypted radio. what would be the advantage of
doing it with a laser other than 'friggin' laser'?

~~~
codezero
What the other comment said. I guess it’s also because of friggin lasers and I
may even be misremembering that part. But a laser would have a smaller beam
diameter and less likely of interception.

------
akira2501
The USSR used buoys extensively during the cold war. Here's a former naval
officer describing the sonar based system:

[https://www.youtube.com/watch?v=Eb6e_-
HvBzw](https://www.youtube.com/watch?v=Eb6e_-HvBzw)

~~~
audiometry
I recently stumbled on this channel. It’s amazing to watch him “twitch stream”
analyzing an underwater recording to pull out all sorts of interesting
insights while only using a consumer, general purpose audio software.

------
walrus01
I just did a Ctrl-f on this comments page, and on the article for "iridium",
and I'm surprised nobody has mentioned the disposable/expendable iridium buoys
yet.

They absolutely exist and come in several varieties. These are not as big a
secret as they were 15 years ago. The USN was the first user of such things,
but other NATO countries have also purchased and deployed them, or developed
their own models.

------
supernova87a
I love reading about stuff like this!

I had 2 questions perpetually on my mind:

1) The article doesn't go into physical sonic wave communication, like
ultrasonic I suppose. Did that ever have applications for submarine comms?

2) I always wonder whether like in the movies, submarines actually have or
ever use the audible ping. Of course, it gives away one's position instantly,
but does such a ping capability even exist still, on modern submarines?

~~~
drtillberg
Re: #2, that is active sonar, which is for useful for locating objects that
are silent, e.g., rocks.[1] It also is very loud and disruptive for whales and
dolphins.[2]

[1]
[https://oceanservice.noaa.gov/facts/sonar.html](https://oceanservice.noaa.gov/facts/sonar.html)

[2] [https://skeptoid.com/episodes/4236](https://skeptoid.com/episodes/4236)

~~~
supernova87a
Ah of course, the issue several years ago when the Navy's testing was causing
whale / dolphin strandings...

------
larrik
> The 228,000 ocean-dwelling species that we know about represents about ten
> percent of the estimated total aquatic species.

I don't buy it. The idea that the deep ocean is full of all this life we
haven't plundered yet seems like a fantasy.

~~~
nickff
They usually make these types of estimates by looking at the rate of new
species discovery, and assuming it will asymptotically approach zero.

