Hiya...

Sort of off topic, but a radio question none the less. I read a few
articles and saw a few space documentaries regarding a possible future space
mission to Jupiter's moon Europa. The theory is that there is an ocean
beneath the frozen surface. The idea of the possible mission is to send a
probe that will melt through the surface ice that is thought to be about two
miles and then, send a "hydro-bot" through the hole. The "hydro-bot" (a
mini submersible probe) will swim around and send live pictures back up to
the mother probe still on the surface. From what I read, it is to be
wireless transmission.

OK.. so... Here is the question....

I got to thinking, that if it is going to be wireless and underwater, it's
probably going to use longwave to transmit. I've read countless times that
long wave is used underwater by subs and underwater research.

Then, I thought.... If you take a long wave receiver to the shore and stick
an antenna/probe into the water, will you be able to pick up any underwater
longwave beacons or hear anything that you coulden't with the antenna just a
few feet above the water, but not in it ???
--
Respectfully,

Michael

Location: New Jersey
Primary Receiver: R-75 with full Kiwa mods
Antennas: G5RV, 200ft "Frankenstein" roof wire
Additional Radios: KA-1101,KA-1102,PL-550,
KA-989, Info-Mate 837, GE-SR III
Westinghouse H-104 (seven tube)
Web Site: http://md_dxing.tripod.com

My first thoughts are that you'll need an appropriate receiver in the hz region
( 1 khz RF) and the second what kind of antenna might you use? I don't think
30 ft of wire will be very efficient.

Also, I think they use very slow binary (carrier on/off) to convey the
messages.

jw
K9RZZ

Then, I thought.... If you take a long wave receiver to the shore and stick
an antenna/probe into the water, will you be able to pick up any underwater
longwave beacons or hear anything that you coulden't with the antenna just a
few feet above the water, but not i

n it ???

Pretty good question Michael, interesting.


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"Michael" wrote in message news:3H7tc.55379$
I got to thinking, that if it is going to be wireless and underwater, it's
probably going to use longwave to transmit. I've read countless times
that
long wave is used underwater by subs and underwater research.

LF or Long waves around 150 kHz are attenuated very quickly in water that's
why to communicate with a submarine you need to go to the ELF band where
subs use 76 Hz , yes 76 Hertz! You would not be able to get a speech
transmission let alone TV pictures on 76Hz, so I don't know what these bots
are going to do. I heard they were going to be wired up anyway.

--
Simon Mason
Anlaby
East Yorkshire.
53°44'N 0°26'W
http://www.simonmason.karoo.net