Question for the Hawaiians here

Discussion in 'General Discussion' started by Airtime, Sep 20, 2014.

  1. Airtime

    Airtime Monkey+++

    I happened across this little article about the Haiku valley.
    Hiking Oahu's Stairway to Heaven ///

    Made me curious about the status of the decommissioned Omega transmitter facility in the valley. Any of the folks who live in Hawaii know?

    I climbed these very ladders and stairs in 1982. My uncle was very high in the Pacific Fleet of the Coast Guard then and when I was visiting back to Hawaii (used to live there) he called the commander of the Omega facility and "asked" them to give me a wonderful tour of the place. Of course they said absolutely to the captain and even allowed my father, brother and a couple local friends to climb these stairs up the ridge. Was a grand day and adventure.

    As background for others and the ham radio guys Omega was a global navigation system that employed signals tranmitted in the range of 10-14 kilohertz. Yes, those are audible frequencies! The Haiku valley was a volcanic crater with the ocean side missing. It is something like a mile and a half across from one side to the other and antenna cables were strung across valley from ridge top to ridge top. It radiated at something like 10,000 watts and the transmitter amps were 10-15 times more than that due the shortened antenna inefficiency if I recall correctly. The valley floor was also laced with a wire and rod network for a better ground plane. Originally this site was a VLF transmitter for submarine communications during WW II and the stairs were carried up and staked to the rock so workers could get up to the antenna bases. It was converted to an Omega transmitter in the early 70s. There were 8-9 transmitters world wide and atleast 3 could be received any where on the planet. Comparing the phase of the signals from the received stations a position within a few miles could be determined. Quite adequate for intercontinental navigation until closer for Loran C or other more precise systems.

    The massive antenna tuning coils and active tuning while the antennas swayed in the wind was so fun to watch. We're talking coils with the biggest being 8-10 feet diameter and maybe 20 feet high with an inner coil that was moved up and down vertically several feet by an all wood structure to tune the coil to balance the changing capacitive reactance of the swaying antenna cables. So crude, brute force and really cool to a recently graduated electrical engineer. And you could actually hear the transmitted frequency from the buzz of the balancing transformer (as I vaguely recall the transmitters were single ended and feedline was balanced).

    Anyway, was curious about what's left, happened to it, etc. Thanks.

    Last edited: Sep 20, 2014
  2. -06

    -06 Monkey+++

    Years ago an antenna was planted in a tremendously long loop in parts of Michigan/Iowa (I think it was allowed) for submarine communications. Have never heard anymore from it. Did it go through?
  3. ghrit

    ghrit Bad company Administrator Founding Member

    Yes. I believe it was deactivated, didn't work as well as satcoms that followed.
  4. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    Jim Creek, in Washington State is still active... VLF is still used to alert submerged Subs to come up and raise the Comm Mast, to collect their Messages.... from the SatComms.... 1.2 Megawatts @ 24.8KHz.... Phase Coherent CW Emissions....
  5. ghrit

    ghrit Bad company Administrator Founding Member

    Nope. Sked is picked up on schedule, not on command. Streaming the long wire has (well used to have to be) to be near the surface, near periscope depth (thus comm mast depth) even VLF long waves don't penetrate all that deep. That there is still experimental work going on doesn't surprise me at all. Back in the 60s and 70s, short sailed boats found that the long wires fouled the screws, so weren't used at all. Don't ask me how I know, I can't tell you.)
  6. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    Auxmen had a ball with rough cold seas, nub plansmen and the floating wire antenna or so I'm told.
    Last edited: Sep 21, 2014
  7. ghrit

    ghrit Bad company Administrator Founding Member

    True. Didn't have to be cold, either.
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