KC8VKZ

In article ,
"Hamguy" wrote:

KC8VKZ

very sad situation:

Kind of strange they don't have any kind of decent ( even primitive)
comm system in place in the mines

In article ,
mike murphy wrote:

In article ,
"Hamguy" wrote:

KC8VKZ

very sad situation:

Kind of strange they don't have any kind of decent ( even primitive)
comm system in place in the mines

Each miner should be carrying personal communications like firefighters.

"Alien" wrote in message
...
In article ,
mike murphy wrote:

In article ,
"Hamguy" wrote:

KC8VKZ

very sad situation:

Kind of strange they don't have any kind of decent ( even primitive)
comm system in place in the mines

Each miner should be carrying personal communications like firefighters.

The problem with that being that when they are two miles deep in the mine,
radio comms are all but worthless. To get comms for the rescue workers, they
had to relay by radio from two points, then by wire from the last relay
point to the command center. One might suggest repeaters every so often, but
these could easily be damaged or destroyed during an explosion or cave-in.

The fire service if they go in a building they have on there belt this PASS
device. will sound so they can find you.
If you pass out and our still for ten minutes.
Thay do not radio for help.

ICM 2000 & ICM 2000 Plus Dragonfly PASS
The ICM 2000 and ICM 2000 Plus are integrated Computer modules
designed to meet the new NFPA-1982, 1998 Edition PASS standard and
NFPA-1981, 1997 Edition SCBA requirements for redundant End-of-Service Time
indicators (EOST).
The ICM 2000 is an all in one combination PASS and redundant alarm
module that can be added to any MSA MMR or BMR SCBA. Simply remove the
shoulder mounted pressure gauge and replace it with the ICM module.

The ICM 2000 Plus is an all in one combination PASS and redundant
alarm with a built in computer system that digitally displays SCBA
performance information. The ICM 2000 Plus also offers a data logging and
data downloading capability to retrieve up to 30 hours of SCBA usage
information. The data provides information about the time of use, air
consumption rate, ambient temperature and alarm activation. Through the
device's IR (Infrared) port, the data can be downloaded to a personal
computer for future evaluation.

Andrews Radiax....

mike murphy wrote:
In article ,
"Hamguy" wrote:


KC8VKZ


very sad situation:

Kind of strange they don't have any kind of decent ( even primitive)
comm system in place in the mines

In article ,
"Brenda Ann" wrote:

"Alien" wrote in message
...
In article ,
mike murphy wrote:

In article ,
"Hamguy" wrote:

KC8VKZ

very sad situation:

Kind of strange they don't have any kind of decent ( even primitive)
comm system in place in the mines

Each miner should be carrying personal communications like firefighters.

The problem with that being that when they are two miles deep in the mine,
radio comms are all but worthless. To get comms for the rescue workers, they
had to relay by radio from two points, then by wire from the last relay
point to the command center. One might suggest repeaters every so often, but
these could easily be damaged or destroyed during an explosion or cave-in.

I thought there were some freq which would pass thru rocks and earth to
great depths. LF perhaps, but that would present other problems. There
must be some way for them to reliably communicate other than by wire.

"Alien" wrote in message
...
In article ,
"Brenda Ann" wrote:

"Alien" wrote in message
...
In article ,
mike murphy wrote:

In article ,
"Hamguy" wrote:

KC8VKZ

very sad situation:

Kind of strange they don't have any kind of decent ( even primitive)
comm system in place in the mines

Each miner should be carrying personal communications like
firefighters.

The problem with that being that when they are two miles deep in the
mine,
radio comms are all but worthless. To get comms for the rescue workers,
they
had to relay by radio from two points, then by wire from the last relay
point to the command center. One might suggest repeaters every so often,
but
these could easily be damaged or destroyed during an explosion or
cave-in.

I thought there were some freq which would pass thru rocks and earth to
great depths. LF perhaps, but that would present other problems. There
must be some way for them to reliably communicate other than by wire.

Lowfer comms require extensive antenna arrays that are not feasible in these
situations. About the only thing I can think of would be to place wired
communications systems with the wires in heavy conduit which is in turn set
into the cave walls and covered with steel and concrete. Perhaps something
like that could reliably survive most hazards of underground mining
(especially if set into the cave floor rather than the walls).

It is all Safety

Will the company go for the cost of a 5 mile long passive antenna in the
portative casing to be reliable for the men's safety? Ok maybe a woman
safety if she goes in.



12 may still be with us if they could have relayed a message. Or solved the
puzzle of the disaster in there last words.

Google "Cave Radio" and "CREG" to learn about specialized low freq cave
communications systems which would have helped in this scenario. Much of
this development is going on overseas.

The word I heard was that the conventional radio system in the mine
failed after the explosion.

It is a shame that the miners don't have a communications system, an
oxygen source and refuge other than a "curtain" under these situations.

My wife and I stayed up watching the "miracle" until it was found untrue
and were quite shocked.

Joe

Brenda Ann wrote:

"Alien" wrote in message
...


In article ,
"Brenda Ann" wrote:



"Alien" wrote in message
...


In article ,
mike murphy wrote:



In article ,
"Hamguy" wrote:



KC8VKZ


very sad situation:

Kind of strange they don't have any kind of decent ( even primitive)
comm system in place in the mines


Each miner should be carrying personal communications like
firefighters.


The problem with that being that when they are two miles deep in the
mine,
radio comms are all but worthless. To get comms for the rescue workers,
they
had to relay by radio from two points, then by wire from the last relay
point to the command center. One might suggest repeaters every so often,
but
these could easily be damaged or destroyed during an explosion or
cave-in.


I thought there were some freq which would pass thru rocks and earth to
great depths. LF perhaps, but that would present other problems. There
must be some way for them to reliably communicate other than by wire.



Lowfer comms require extensive antenna arrays that are not feasible in these
situations. About the only thing I can think of would be to place wired
communications systems with the wires in heavy conduit which is in turn set
into the cave walls and covered with steel and concrete. Perhaps something
like that could reliably survive most hazards of underground mining
(especially if set into the cave floor rather than the walls).





--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P