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Could this device be built?

Discussion in 'Electronic Repair' started by Spob, Aug 19, 2007.

  1. Arny Krueger

    Arny Krueger Guest

    Heating of the radome might also be a problem.
  2. Guest

    No, but I have enough years of experience with RF in general and radar
    in particular to know building a phased array requires precise phase
    (or frequency) control and you can't do that with an ultra wideband
    device, which has a bandwidth of 500 Mhz.

    Such a device may make a great wireless LAN at ranges of tens of yards,
    but is not the device of choice for building a phased array anything.
  3. Hal Murray

    Hal Murray Guest

    No, but I have enough years of experience with RF in general and radar
    What is the bandwidth of modern radars? I'd expect it to be
    wide and using spread spectrum tricks to make jaming harder.
  4. Rich Grise

    Rich Grise Guest

    No, the Wild Weasels were recce. The EWO (Electronic Warfare Officer),
    ususally the GIB (Guy In Back), had a spectrum-analyzer display, to
    sniff out the jammers (and maybe even comm.). I don't know exactly what
    they did with the info, other than evasive maneuvers, but it gave a pretty
    good idea of the radar environment they were flying into.

    I'm sure they carried their own jammers, but so did all of the other

  5. Rich Grise

    Rich Grise Guest

  6. Benj

    Benj Guest

    Zappers are great solid state destroyers (transistors make better
    fuses than fuses) But you have to get close enough to zap the circuit
    boards. (Work great on Computer mother boards!)
    Yes, although every wire in the player is a potential antenna
    especially for high frequency (radar) EMP.

    Electronics have antennas. Bugs have antennae!

  7. John Larkin

    John Larkin Guest

    On Tue, 21 Aug 2007 15:41:13 -0500,

    At a minumum!
    Spiffy modern radars hop and chirp, both of which broaden the working

    With modern signal processing, wider radar bandwidth improves
    resolution. You can do all sorts of fun stuff with 1000 antennas and a
    few teraflops of compute power.

    All the major powers - US, Russia, France, Germany, China, Israel, UK
    - are working on HPM weapons and array radars. The Brits call their
    projects "Suave" and "Virus." MBDA and BAE are major players.

    Google "mbda hpm" and "bae hpm", and believe it or don't.

  8. Scott Dorsey

    Scott Dorsey Guest

    At the time, the Bad Guys only had a limited number of standard radar
    platforms. So with a spiral antenna and a spectrum analyzer, you could
    pretty quickly tell what was in the neighborhood from the emission
    frequency and the rough envelope. And with a directional antenna and a
    little hunting around, you could pretty quickly localize the direction of
    the source. So with a pretty limited toolkit, you could tell what the
    bad guys were (ie. targetting radar, sky search, airborne radar) and where
    they were. Likewise you could very easily tell a legitimate radar system
    from a jammer from the spectrum, and the jamming platforms were fairly

    Doing this while being shot at is left as an exercise to the student and
    may not be as easy as identifing spectral envelopes in an air-conditioned
  9. Guest

    Depends on what bandwidth you are talking about.

    For the instananeous transmitted frequency, narrow.

    Some military stuff has used frequency hopping since WWII to make it
    harder to jam.

    Frequency hopping is a spread spectrum technique and the bandwidth
    over time is wide.

    You could make a spread spectrum, phased array radar, but the frequency,
    phase, and amplitude of all the emitters has to be precisely controlled
    to form the beam, which implies that for a given pulse, all the
    emitters are transmitting very close to the same frequency.

    The next pulse may be hundreds of megahertz away, but that's what
    processors are for.
  10. Guest

    I would hope so since the techniques have been around for at least
    a quarter century.
    Narrower pulse widths and good receivers improves resolution.
    A search for "mbda hpm" returns:

    Your search - "mbda hpm" - did not match any documents.

    And "bae hpm" returns:
    SIMPLE = T / file conforms to fits standard BITPIX = 16 / number
    You are mixing apples, oranges and cherries.

    Frequency agile radar, rudimentary spread spectrum, was originally
    developed in WWII.

    Phased array radars have been around for decades.

    And everyone WANTS a death ray, but no one has made a practical one yet.

  11. The bandwidth of a radar pulse is determined by the required resolution
    of the distance. Thus there is generally no point to increase the pulse
    bandwidth beyond ~100Mhz unless for the very special tasks like a target
    feature recognition. However the carrier frequency and the spreading
    code can vary from pulse to pulse.

    Vladimir Vassilevsky

    DSP and Mixed Signal Design Consultant
  12. Fred Bloggs

    Fred Bloggs Guest

    Frequency agile Ku band transmission? What kind of tube did they use for
    that? Wondering why the Ku band could not just take a handoff and do the
    tracking on its own, must not have been a stable track. What kind of
    cheap ill-begotten antenna gets you less angular resolution at Ku band
    than X-band?
  13. John Larkin

    John Larkin Guest

    Don't type the quote marks. Geez.

  14. Scott Dorsey

    Scott Dorsey Guest

    There are plenty of commercial death rays in the 54-72 MC and 76-88 MC
    bands. They don't cause death directly, but transmissions on these
    frequencies can cause severe brain damage even at low levels when demodulated
    and viewed. A number of studies have shown long-term exposure to cause
    all sorts of problems in children.
  15. Terry Given

    Terry Given Guest

    AIUI they are termed "brain-death rays"

  16. Guest

    Then don't say Google "mbda hpm" and "bae hpm".

    And if I don't use quotes, will I get information on phased array
    radars, phased array death rays, or phased array, spread spectrum,
    death ray radars?
  17. Guest

    Not a problem if you buy my aluminum foil long johns.
  18. Tom Potter

    Tom Potter Guest

    It seems to me,
    that with modern electronics and information technology,
    that a high resolution, handheld, RADAR system is possible.

    You could quasi-randomly modulate (Variable transmit and listen periods),
    a solid state microwave oscillator (Gunn Diode)
    with a digital code with good correlation properties (Gold Code),

    cross-correlate the echoes received when in the listen mode
    with the Gold Code, then cross-correlate the correlations
    from the echoes with stored geo-patterns downloaded
    from a Google-Earth like data base covering the area of operation,

    compare adjacent (In time) echo returns to spot moving targets,
    then present the pattern on a small, solid state, color display
    that shows the Google-Earth like picture of the area,
    with super-imposed moving targets.

    One would not need a directional antenna,
    nor high power for such a device,
    but it would be necessary to sweep the device around
    to build up a good correlation of
    the area as one's body and other things
    would block the signals and,
    even though the Google-Earth like picture,
    and the location of the RADAR would still be valid,
    but blocked moving targets would not be detected.

    Note that if a map of the area of operation is downloaded
    into the system, and a set of times from the radar to fixed
    targets is compared to the map, one could quickly correlate the
    map with the echoes and determine where one is.

    With such a device, one could move around,
    and see where they were on a moving Google-Earth-like picture,
    and see the moving targets about them,
    perhaps even colored and shaped by the RADAR signatures
    of the targets. (People, cars, tanks, trains, an incoming missle, etc.)

    Note that for many situations that such a device could replace GPS.
    Just like GPS, after the device determines where one is,
    it would be able to compute changes in position quickly.

    Hey maybe, I should patent this device?

    As I mentioned in old posts,
    I used "Data Mining" back in the 1980's
    in my businesses and applied for a patent on "Data Mining"
    just when they began to allow software to be patented,
    but I decided not to complicate my life,
    and didn't complete the patent.

    In other words,
    if you want to commercialize this idea for non-military applications,
    go for it.

    As any entrepreneur knows,
    ideas are a dime a dozen,
    and what requires blood, sweat and tears
    is getting an idea to the marketplace.

    The bottom line is,
    no one should be able to hold progress hostage
    with a patent, that is obvious to many,
    as the state of the art exposes new approaches.

    Tom Potter

    *** Time Magazine Person of the Year 2006 ***
    *** May 2007 Anti-Bigot Award ***
  19. JW

    JW Guest

    I would assume that an automotive CD player would also be equipped with an
    AM/FM tuner, wouldn't you? The OP just mentions a "stereo", anyway.
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