Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!brl-smoke!floyd From: floyd@brl-smoke.ARPA (Floyd C. Wofford) Newsgroups: sci.electronics Subject: Re: Robocop/ECM/ECCM/EW Message-ID: <7535@brl-smoke.ARPA> Date: 24 Mar 88 14:20:58 GMT References: <1342@titan.camcon.uucp> Reply-To: floyd@brl.arpa (Floyd C. Wofford) Organization: Ballistic Research Laboratory Lines: 62 In article <1342@titan.camcon.uucp> mb@camcon.uucp (Mike Bell) writes: >Aw hell! Haven't you guys heard that F*rd have been working for years >on the so-called `stealth car' for the DoD. It features ultra-smooth >body contours to reduce reflection and minimise drag, a low radar >cross-section engine using specially-developed ceramics, glass fibre for >the bodywork, glass for the windows, etc. It is painted with this >really special paint which not only absorbs radar electro-magnetic >emissions, but also the visible spectrum as well. > >You can have it in any colour you like, so long as it's black:-) Actually there is another color, Seafoam Green. Black though is infinitely preferrable. In a more serious, if not more speculative, mind I have a question for thought. I am intrigued by passive means of countermeasure. They are or can be cheaper (chicken wire, flares, chaff, compost heaps, etc. etc.) and more fun. They are usually legal. Ok, for those of you in the IEEE's digital signal processing society (ASSP), the Jan. '88 issue of the ASSP Magazine (not the Transactions) has a somewhat provocative article. I am referring to the Schroeder article. Mr. Schroeder seems to be a quixotic character, an APPLIED number theorist. His article seems to be quite interesting with perhaps some utility to the passive ECM arguement here. Mr Schroeder builds "diffraction gratings" with depths and spacings derived from results in number theory (powers of primitive roots to construct reflection coefficients pg.8). The pattern attenuates the zeroeth diffraction order (reduced "radial" return). The energy is effectively scattered everywhere except the direction from which it came. Note, this is my interpretation of the paper, and not necessarily what Mr. Schroeder said. Since effectively, no energy travels back to the detector, the man does not see you. I believe Corvettes and Fiero bodies are made from composite materials. Are these invisible at X-band? Are there others (no resonant dipoles in polymer chains, etc.) suited to make car bodies! If so, the inner surface could be molded to an appropriate pattern (passive ECM-diffraction grating) and painted with a reflective paint. If my train of thought is clear, the outer surface would be attractive (black or seafoam green) and the inner surface would be interesting. Ok, you groovy guys and gals. Chew this idea up. It came from reading the article and the recent discussion on the net. Why will it not work? Why will it work? If it can work, it is probably being worked on right now. The article implied as much. In another vein, I was serious in my follow-up posting a few weeks ago about an absorbing paint. A couple of years ago a friend of mine saw an article in the trade magazines (the same ones you guys saw all your active devices) for a can of spray for your car. It had all the usual hype about how it beat everything that radiated. The follow up was that the person who ran the article wound up in court. He had no product. He got an incredible response from the article (a can was ~$17) and was going to pay someone to invent the product. Many of us chuckled about the article. All of us would have bought a case of the stuff if it was legitimate. So put on your thinking caps. Can we beat 'em at their game? Remember, they started it (none of my friends have radar guns to check if they are speeding)! floyd@brl.arpa