They probly use blue light any way.
Some years ago I designed a power supply for an 155 mm artillery shell or a rocket. The thing only had to work for about 1 minute. It powered a transmitter which would be used to call back SAC bombers in the event that they were on a bombing mission. The idea was to get the transmitter high into the air for maximum transmission distance.
In article , daestrom wrote: [.. no trailing antenna..]
I guess I should have been clearer. I meant they don't trail an antenna for the ELF we were talking about.
"bushbadee" wrote: [ELF and submarine comms in general]
Perhaps they do they do, but that doesn't mean they don't also use ELF, VLF, acoustic signaling and a variety of other systems.
Tim
On a sunny day (Thu, 13 May 2004 19:28:39 -0700) it happened DarkMatter wrote in :
Electronically and mechanically and optically and physically yes. But the psychological effect is real. man goes out and buys green marker, spends money, talks with people how he will use that marker, people say: 'OOOOWW I did not know that' No man feels good, sits down, marks CD or DVD and is more relaxed. As his muscles are more relaxed, and the grinding sound of the teeth has stopped a bit, the signal to noise has increased dramatically, and he can really enjoy. I have green CD safe marker for sale, starting at 750$ a piece (ex tax). The blue ones are already available to, for blue light DVD it is already here. Those need to be listened to with orange glasses btw, to avoid visual feedback. JP
This reminds me of another example of the extreme end of communications theory. A couple years ago I interviewed with a company that makes remote readable electric meters. They put a module in the bottom of the meter that reads and counts the rotation of the disk and sends a signal back to equipment placed at certain places around the power grid to collect meter readings.
The signals were sent over the power grid in a band of something like 10 or 20 Hz centered around 60 Hz so it could get through transformers. They crammed thousands of parallel data channels hundredths of a Hz apart into that band. Time to transmit ONE BIT was something like 20 minutes.
They claimed in testing they had received the signal up to 100 miles away.
About 30 years ago I worked with a fellow who joked: "There are just as many octaves BELOW one hertz as there are ABOVE one hertz."
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