Callsign
ad: tentec
Page 1 of 2 1 2 LastLast
Results 1 to 10 of 12

Thread: Texting Underground Can Save Lives And Caves

ad: L-HROutlet
ad: l-assoc
ad: l-tentec
ad: l-gcopper
ad: l-rl
ad: l-Waters
ad: l-innov
ad: l-WarrenG
ad: l-sarc
  1. #1

    Default Texting Underground Can Save Lives And Caves

    http://www.npr.org/templates/story/s...17&ft=1&f=1001

    Alexander Kendrick, 16, won the 2009 International Science Fair for inventing this cave-texting device. The award got the teen from Los Alamos, N.M., a new computer, a trip to Switzerland and $12,000.
    .....
    The device is something like a computer attached to a ham radio. It transmits data using low-frequency radio waves that can penetrate rock more easily than high-frequency transmissions, like those in FM broadcasts.

    If this test succeeded, it would be the deepest known underground digital communication ever to take place in the United States.

  2. #2

    Default

    that is just a really cool article! I wish they had included some details on radios and freqs they are using, but still, good work kid!

    73

  3. #3
    Join Date
    Oct 2002
    Location
    Schertz, Texas
    Posts
    313

    Default

    This is a better article and has a nice pic of the antenna!

    http://www.engadget.com/2010/02/01/t...d-communicati/


    -Mark

  4. #4

    Default Cave Radio

    It is wonderful to see this article carried widely, with the excellent work of the young cave radio enthusiast Alexander Kendrick.

    Low Frequency (LF) or Very Low Frequency (VLF) in the audio range is often used for cave radio, especially for RDF/radiolocation using the loop null method. Efficient small size loop antennas at these frequencies have very narrow bandwidth... from a few hertz at VLF up to about 2kHz at LF.

    But MF and HF also works great for communications, and coil-loaded whip antennas or wire antennas on the ground, can be used for SSB HTs on HF. For those who are interested in Cave Radio, please see "Speleonics", the journal of the Communications and Electronics Section of the National Speleological Society (NSS).

    Here is an issue of Speleonics with an article on SSB and CW on both LF and HF in caves: 185kHz Radiolocation and 7MHz Communication Experiments in Bigfoot Cave


    One of my homebrew 185kHz SSB/CW/beacon cave radios


    185kHz Pedestrian Mobile cave radio RDF loop antenna and 7MHz whip antenna in use above the passages of Bigfoot Cave in California.

    Hams who are also cave radio operators often use the ham bands for cave radio. But there are also several areas of spectrum that allow unlicensed operation, such as the LoFER bands. Typically, SSB is often used for voice, above 70 kHz. CW or beep beacons are used for radiolocation below 200kHz. PSK or FSK is used for text/data. The frequencies below 500kHz typically use either earth dipole or loop antennas for communications. Loop antennas work well for RDF survey work. For HF communications, wire antennas, guide wires, or portable whip antennas are used for communications. Here are some of the common frequencies used for cave radio.

    100-4000Hz (Audio band) direct voice audio amplifier to antennas or guide wire
    715Hz (Audio band) CW beacons for RDF/Radiolocation
    3496Hz (Audio band) CW beacons for RDF/Radiolocation
    136kHz (135.7kHz -137.8 kHz Amateur Band) International
    185kHz (160 kHz - 190 kHz LowFER band) USA/Canada
    3885kHz (75m Amateur Band) for ham cave radio operators
    3996kHz (75m Amateur Band) for ham cave radio operators
    7095kHz (40m Amateur Band) for ham cave radio operators
    7240kHz (40m Amateur Band) for ham cave radio operators
    27MHz (CB Band, SSB, AM, FM) direct or with guide wire
    VHF (various bands) direct in lava caves or with guide wire in other rock
    UHF (various bands) with guide wire

    Bonnie KQ6XA
    NSS 34939
    Last edited by KQ6XA; 02-02-2010 at 06:12 PM.
    Bonnie Crystal KQ6XA
    Founder: HFpack hfpack.com | HFLINK hflink.com

  5. #5
    Join Date
    Sep 2009
    Location
    Eagle Mountain, UT
    Posts
    91

    Default

    Funny, I just read this on one of my Abandoned Mine websites and was trying to do a search for more info and found QRZ.

    I think it's awesome and it sounds like that kid is pretty bright. I think it's impressive! So would this require a license? Didn't see his name in the FCC database...
    [SIZE=2][COLOR=red][FONT=system]Tobin Gardner
    95 Land Cruiser - Factory locked, 4" OME, 33x12.50 Swampers, Safari Snorkel, Icom ham, Cobra CB
    [/FONT][/COLOR][/SIZE][COLOR=red][FONT=system]
    [SIZE=3][URL="http://www.imrdb.org"]imrdb.org-The Internet Movie Radio Database (Ham & CB)[/URL]
    [URL="http://www.impdb.org"]impdb.org-The Internet Movie Plane Database[/URL][/SIZE][/FONT][/COLOR]

  6. #6
    Join Date
    Sep 2009
    Location
    Eagle Mountain, UT
    Posts
    91

    Default

    Quote Originally Posted by KQ6XA View Post
    It is wonderful to see this article carried widely, with the excellent work of the young cave radio enthusiast Alexander Kendrick.

    For those who are interested in Cave Radio, please see "Speleonics", the journal of the Communications and Electronics Section of the National Speleological Society (NSS).
    So Bonnie, would this be pretty similar? Or identical?

    (We were posting at the same time)
    [SIZE=2][COLOR=red][FONT=system]Tobin Gardner
    95 Land Cruiser - Factory locked, 4" OME, 33x12.50 Swampers, Safari Snorkel, Icom ham, Cobra CB
    [/FONT][/COLOR][/SIZE][COLOR=red][FONT=system]
    [SIZE=3][URL="http://www.imrdb.org"]imrdb.org-The Internet Movie Radio Database (Ham & CB)[/URL]
    [URL="http://www.impdb.org"]impdb.org-The Internet Movie Plane Database[/URL][/SIZE][/FONT][/COLOR]

  7. #7

    Default

    So there may finally be something that can provide limited communications to coal miners as mandated (by people with absolutely no comprehension of RF communications) following the Sago Mine Disaster.

  8. #8

    Default

    Quote Originally Posted by KC8PBS View Post
    So there may finally be something that can provide limited communications to coal miners as mandated (by people with absolutely no comprehension of RF communications) following the Sago Mine Disaster.
    There's been a system around for years, called "The Mine Radio" Works on a highly inductive loop system. The UK National Coal Board pioneered it and spent millions developing it in the late 60's through to the end of UK nationalised coal industry.
    Many mines around the world are using the system.
    Coal mines are unique when it comes to RF propagation, they tend to be deep, they tend to have lots of steelwork in them as supports etc. To overcome that, a "guide wire" grounded at one end is run along a main travelling road, useful range is a max 1.5KMs . (Repeaters are used after that and at every 1KM intervals.)
    There is another system being developed here in the US, it's already being used, it is certified for hazardous locations, but is more of a paging system and automatic tracking system for miners underground. Again, it requires a "guide wire" along roadways to work successfully.

  9. #9

    Default Mine radio

    Here's a link

    http://sanantonio.bizjournals.com/al...1/daily14.html

    He might have 'set a record' but there appears to be a fair amount of literature on the subject.

    Obviously, he had to make the antennas and 'radio' equipment, probably VLF.....

    New?? not sure.....might be first time keyboard was use for texting.....

  10. #10
    Join Date
    Feb 2005
    Location
    Oak Ridge, Tn
    Posts
    3

    Default Spread the word

    It would be nice to see an article in QST, QEX or CQ on this topic. I don't think it is "common" knowledge with most hams.

    Seems like a very active community and it is very interesting reading.

    Congrats on the science fair victory Alexander.

    Thanks for your links Bonnie, will definitely read them.

    73,
    Julius
    n2wn

Page 1 of 2 1 2 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •