Batboard

We should, once again, thank Motorola for the lives saved. Radios underground. One junk or poorly maintained radio and no one would have known....

Here is a quote:

"All of a sudden, a call came in on the walkie-talkie," said Doug Custer, a co-worker of the trapped men, who escaped the flooded mine. "They said, 'We hit water -- get out.' In a mine, we joke around a lot, but we know a call like this is serious so we dropped our tools, shut off the machinery and got out of there as fast as we could."

Ra

Thank Motorola ??? They far from have an exclusive on 2 way radio
technology. Interesting how they make some of their products here, charge us one price and after going thru the expense of exporting them elsewhere sell them cheaper there. If anything they should be cheaper
in the US market. I've lived very near to their Plantation factory and it's interesting that many public safety agencies in the area did not use their
products. Personally I like their products but their business practices leave a LOT to be desired.

While we're talking about mining radio, interesting how one crew was able
to warn the other but they couldn't contact the crew some 240 ft. down
during the rescue ? (Relying on tapping sounds to verify they were OK). Anyone know- do all miners carry radios? Any problem with penetrating
240 ft. down ?

Ah, You are likely right, likely right.

All companies are crooks now. But you see I am an old old guy and in my Motorola days they did everything for us that they possibly could.

Free radios, full support - anything. Motorola supported us service guys to a perfect tee. They knew us by name even in Chicago. We were the guys who kept that stuff working and they needed and fully supported us - If we found a design error we called Chicago and they fixed it on the line by days end - and called back to say thanks. From what YOU say it is all gone now. Woulden't wonder.

In those days we even sang (in our shop) that Motorola song, remember it ?-- Same toon as the happy birthday song.....Motorola Fm, Motorola FM, Mooootorola, Moootowrola... Motorola FM. Repeat.

Sounds so silly now, but we were proud to be on that team, each and every one of us. We had to be good, fast and very intuitive when it came to repair - otherwise one did not make it.

We were on the cutting edge and could walk in the back door of any police station or public service agency and be known by name. We could go anywhere, day or night, and do just about anything; we were Motorola guys and we made it all happen.

We were young too and if we got in trouble doing something stupid those same public saftey agencies fixed it for us; yes they did.

I could be stopped slightly speeding at 3am and as soon as the officer heard that I was a Motorola guy going on a call -- Presto - no problem mate.

Are you are too young to remember the excitement when the first handheld came out. Knock em' all you want but then it WAS different, exciting, necessary and fun, way fun.

Anyway they used Motorola units down in that mine, they said so.

Cheers

Radio is fairly unreliable in many parts of mines. Most of the lighting is RF exited and causes interference with everything around. RF lighting is used to prevent arcing if a cable is ruptured. A few years back, I worked for a place that repaired longwall lighting equipment for the mining industry and learned first hand how 'dirty' the RF is from these lights. Just in case anyone wants to know, the frequency is approximately 55kc.

As for the radios that are used in mining, I've seen them carry anything from Motorola to ICOM, EFJ, BK and even FRS when I went in the field several times.

Most communications underground are performed via wired sets- either electrically wired or RF wired.

Very interesting Ra, must have been great to work in this field as the technology was developing and working for an outfit on the cutting edge
where it sounded like development was a mutual effort. Unfortunately
greed and lack of loyalty seems to be the way now a days. I think we've
all lost a lot when many of the 'old school' values were abandoned. Big
business seems to lead the band in this direction, very unfortunate.

Thanks for the response Jim, I can see how RF lighting could do a job on
wireless comm's. I had read an article in either 'Communications' or MRT
some years back on tunnel communications and was very surprised at the
lack of range in that type of environment, guess some of those principles
would be similar to what's found in a mine.

The underground radio system is a
different field of it's own. They can use many different
types of antennas. The one I see installed is the leaky
feeder type.It is co-ax the has 16 equally spaced wires
placed as the return around the centre wire.It is 75 ohms.
It losses 17 db signal at 350 meters. and amp. at 20 db
is installed at the 350 meters ends.The cable is run the total
lenght of the mine.The portables must be within fifty feet
of this antenna.You set up a repeater to connect to
this cable.Each 10,000 feet you place 12 volt power on the line
for voltage drops.You has a signal sent to the computer to
tell what addressed amp is bad. you monitor rf in
rf out and voltage on each amp.It is the same as cable tv network
but in two directions. GREAT system
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