House pseudo scientist
Now I can sleep soundly, thank you.
Stanley the senile sheeple
-----Original Message-----
From: schalestock <schalestock@xxxxxxxx>
To: sparkscoffee <sparkscoffee@xxxxxxxxxxxxx>
Sent: Sun, Aug 2, 2015 12:19 pm
Subject: [sparkscoffee] Re: How to track submarines
Stanley, (with apologies to everyone else that already knows this)
GPS satellites are in geosynchronous orbit. This means they orbit at the same
speed as the earth's rotation. This allows them to remain over a fixed point
over the earth. But the ocean is like a Faraday shield. It blocks any RF from
penetrating very far beneath the surface, especially in the uhf band the
satellites operate at. That's why a nuke boat has to surface to transmit. It
can however (as DR mentioned) receive a message via ELF which has severe
limitations. The frequency used is 75 Hertz. I'll let you calculate the
wavelength. But its so long, they have had to build enormous buried antenna
system to make it work.
The coding used for US military ELF transmissions employed a Reed-Solomon
error correction code using 64 symbols, each represented by a very long
pseudo-random sequence. The entire transmission was then encrypted. The
advantages of such a technique are that by correlating multiple transmissions,
a message could be completed even with very low signal-to-noise ratios, and
because only a very few pseudo-random sequences represented actual message
characters, there was a very high probability that if a message was
successfully received, it was a valid message ( anti-spoofing).
The communication link is one-way. No submarine could have its own ELF
transmitter on board, due to the sheer size of such a device. Attempts to
design a transmitter which can be immersed in the sea or flown on an aircraft
were soon abandoned.
Due to the limited bandwidth, information can only be transmitted very slowly,
on the order of a few characters per minute (see Shannon's coding theorem).
Thus it is reasonable to assume that the actual messages were mostly generic
instructions or requests to establish a different form of two-way communication
with the relevant authority.
The way we know the position of Russian submarines is pretty simple. We simply
assign one of our fast attack boats to shadow the Russian boomer when it leaves
port. The theory being that if nuclear war was imminent, our boat would
immediately sink the Russian.
But this is the ONLY way we can currently know a Russian submarine's location
while submerged. GPS doesn't enter into to it.
Hope this clears it up for you.
JS
---------- Original Message ----------
From: "" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender "sblumen123@xxxxxxx"
for DMARC)
To: sparkscoffee@xxxxxxxxxxxxx
Subject: [sparkscoffee] How to track submarines
Date: Sat, 1 Aug 2015 15:48:17 -0400
JS, Lee pixiehat and to whom it may concern
Now I remember, no ifs. ands, or buts, a network of ocean bottom sensors were
placed and terminated at a central monitor station
manned by Russian and American techs. How come you fellers with comic book
mentalities couldn't figure it out? tsk, tsk, tsk,
Senile Stanley wins again and again and again.
Great to be 90, hope you fellers can make it and enjoy the benefits.
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