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KD5NJR > TECH 02.05.16 01:41l 48 Lines 1920 Bytes #999 (0) @ WW
BID : 4YXEYFCDA9WS
Read: GUEST
Subj: Re:Hydraulic Telegraph
Path: IW8PGT<HB9CSR<IK2XDE<DB0RES<DB0OVN<DB0IUZ<DB0GOS<ON0AR<OZ5BBS<CX2SA<
N0KFQ<AE5ME
Sent: 160501/2319Z 36740@AE5ME.#NEOK.OK.USA.NOAM BPQ1.4.64
this is really pretty cool.
It's really an optical-based system, but the pot of water with the markings is a cypher or maybe compression system.
Instead of sending 26 symbols (A-Z), the operator only sends the open / close commands for the valve. There is a compression down to 2 bits (open and close) maybe 2 symbols.
Of course, the drawback is time for the water to drain out.
And maybe expending more torch fuel.
So we could talk about signal to noise ratio if we knew something about about torch brightness , aka : power out.
The messages.... you gotta lay them out clever or you stop to add water.
Fun stuff.
Scott
kd5njr
----- Message from kf5jrv@kb0wsa.mo.usa.na sent 2016/04/27 02:06 -----
Message ID: 2034_KF5JRV
Date: 2016/04/27 02:06
From: kf5jrv@kb0wsa.mo.usa.na
To: tech@ww
Source: AE5ME
Subject: Hydraulic Telegraph
R:160425/1124Z 36338@AE5ME.#NEOK.OK.USA.NOAM BPQ1.4.64
R:160425/1119Z 91686@N0KFQ.#SWMO.MO.USA.NA BPQ1.4.65
R:160425/1119Z 2034@KF5JRV.#NWAR.AR.USA.NA BPQ1.4.65
The Hydraulic Telegraph 350 BCE
According to Polybius, a Greek historian of the Hellenistic
period, Aeneas Tacticus, one of the earliest Greek writers
on the art of war, invented the hydraulic telegraph about 350 BCE. It
was a semaphore system used during the First Punic War to
send messages between Sicily and Carthage.
"The system involved identical containers on separate hills; each container
would be filled with water, and a vertical rod floated within. The rods were
inscribed with various predetermined codes.
"To send a message, the sending operator would use a torch to signal
the receiving operator; once the two were synchronized, they would
simultaneously open the spigots at the bottom of their containers.
Water would drain out until the water level reached the desired code,
at which point the sender would lower his torch, and the operators
would simultaneously close their spigots."
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