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Build Your Own RADAR

Discussion in 'Homebrew and Kit Projects' started by AF6LJ, Apr 29, 2012.

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  1. AF6LJ

    AF6LJ Ham Member

    I saw this over on Hack A Day and found most interesting.
    This is right up the Ham Radio alley.

    Build your own radar system

    posted Apr 28th 2012 9:01am by Mike Szczys
    filed under: cons, radio hacks
    [​IMG]
    How we missed this one is anybody’s guess, but one of the presentations at DEFCON last year covers a DIY radar build. [Michael Scarito] talks about the concepts behind radar, and then goes on to show that it’s not too hard or expensive to build a setup of your own. We’ve embedded his 45 minute talk after the break.
    The two large pieces of hardware above should look familiar. They’re descendents of a favorite hacking project, the cantenna. The can-based long-range antenna is most popular with WiFi applications, but we’ve seen it used for Bluetooth as well and it’s not surprising to see it here. The rest is a lot of sensing hardware and enough math crammed into the coding to make your ears droop.
    If you make it far enough (exactly 39 minutes into the talk) [Michael] shares some links for more information on the build. We think living vicariously is enough for us, but if you manage to build your own setup don’t forget to post a project log!
    [via Dangerous Prototypes]

    [video=youtube;MViVyocQhVw]http://www.youtube.com/watch?feature=player_embedded&v=MViVyocQhVw[/video]
     
  2. K7MEM

    K7MEM Ham Member

    Thanks Sue. That was a pretty good introduction to Synthetic Aperture Radar (SAR). It's a difficult task to try and cover a technology that had been around for over 50 years in a single presentation. It would be good introduction for new engineers, especially if the language was cleaned up a bit. Someone wrote that the language was nothing worse than normal workplace conversational language. Maybe 20 or 25 year ago, but not any more. It only detracts from the presentation. I have seen many a career go bad because of someone assuming that it's normal. I am sure it will come up at his next review.

    I was part of the build, delivery, and maintenance of the first digital SAR processor. This was around 1975. Before that, processing was optical. The processor I worked on had four, 6 foot tall, 19" rack cabinets full of electronics. These were separate from the console. Each cabinet was powered by a 10 Volt/500 Amp power supply. One cabinet was for processing "range" and the other three were for "azimuth" processing. The "azimuth" processor was mostly memory. But this was before high speed, high density static rams were abundant. So the memory consisted of thousands of 1K shift registers.

    There were so many integrated circuits in the complete processor that the "Mean Time Between Failure" (MTBF) was calculated to be about 15 minutes. However, the system was very failure tolerant and had a rather unique "Built In Test Equipment" (BITE) capability. This allowed a support person to determine which of the >800 circuit boards was bad. You could even turn off one complete cabinet of "azimuth" memory and still run the processor at half resolution. THE BITE ran all the time so if anything failed during processing you would just hot swap the bad board with a good one and continue processing.

    The biggest issue was heat. It took two 5 ton air conditioners, that were ducted directly into the cabinets, to keep the processing cabinets from melting down.
     
  3. AF6LJ

    AF6LJ Ham Member

    I agree the language left something to be sesired, fortunately the number of times language was an issue could be counted on one hand. (barely). I had read about some of this stuff in the mid to late eighties and found it quite fascinating.
     
  4. AF6LJ

    AF6LJ Ham Member

    I would also point out some of the comments on the article are interesting.
     
  5. K9STH

    K9STH Ham Member

    A friend of mine, down in Corsicana, Texas, built a complete doppler radar system in the late 1980s. Although was not an amateur radio operator at the time, he was heavily involved in the commercial two-way industry. For a long time, all of the Dallas / Fort Worth television stations relied on this radar for their weather reports.

    The radar was installed in a concrete block structure with a large radome on top. I don't remember exactly the diameter of the dish but I believe that it was between 8 feet and 12 feet in diameter!

    I did a search in data base here on QRZ.com and find that he now has an Amateur Extra Class license!

    Glen, K9STH
     
  6. G0HZU

    G0HZU QRZ Member

    Back in the 1990s I helped design various non linear radar systems for looking through walls for certain types of device. With this type of radar you look for echo signals that get generated from non linearities in the target devices. This helps discriminate against normal clutter. It was a very interesting project although the range was very limited. Maybe 15 metres.
     
  7. KM1H

    KM1H Ham Member

    My last job before retiring was R&D at BAE Systems, Nashua, NH for the various military avionics contracts. Some very interesting features were developed.

    Carl
     
  8. N0SYA

    N0SYA Ham Member

    Hmm. What was that quote? The first equation drops the audience by half? Something like that. Neat anways!
     
  9. K7MEM

    K7MEM Ham Member

    The last program that I was on, before I retired, was partnered with BAE. BAE supplied the core software for our development effort. I had to travel to Nashua several times for meetings. I found it to be a very nice area and the people were generally very nice to work with. It was also nice to find another company that worked well in a Unix environment.
     
  10. AF6LJ

    AF6LJ Ham Member

    That is usually the case, while math isn't my strong suite I'm not afraid of it.
    :)
     
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